Sun, 27 Jul 2008 07:40:26 BST CiteULike: dcastro's Itoh http://www.citeulike.org/user/dcastro/author/Itoh CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/3021116 <i>Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1478-1481 vol.3.</i><br /><br />The authors describe the preliminary designs of two different types of microstrip antennas, i.e., those providing dual-frequency circularly-polarized (CP) operation; and enhanced low-angle radiation. The first type of antennas was designed to operate at the GPS (Global Positioning System) frequencies of 1.227 and 1.575 GHz, and was fabricated by using a novel combination of recessed cavity and patch type of resonators. For the second type of antenna, achieving enhanced gain at lower angles without sacrificing the CP performance turned out to be a difficult challenge. After many unsuccessful attempts, a preliminary design that employed a pyramidal configuration appeared to exhibit good promise and favorable potential for further improvement Microstrip patch antennas for GPS applications R Mittra R Yang M Itoh M Arakawa doi:10.1109/APS.1993.385474 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1478-1481 vol.3. 2008-07-19T17:10:57-00:00 1993 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest 1478 1481 vol.3 antenna application gps microstrip patch http://www.citeulike.org/user/dcastro/article/2941928 <i>Journal of Applied Physics, Vol. 90, No. 11. (2001), pp. 5483-5486.</i><br /><br />View This Record in Scopus Full-wave verification of the fundamental properties of left-handed materials in waveguide configurations C Caloz CC Chang T Itoh Journal of Applied Physics, Vol. 90, No. 11. (2001), pp. 5483-5486. 2008-06-29T18:02:13-00:00 2001 Journal of Applied Physics 90 11 5483 5486 AIP crlh lh metamaterial http://www.citeulike.org/user/dcastro/article/2883732 <i>Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 29, No. 1. (1981), pp. 63-68.</i><br /><br />A method for analyzing characterisitcs of open microstrip disk structures is presented. The method is based on the spectral domain immittance matrix approach, and all the wave phenomena associated with the structures are incorporated. The method provides a number of unique and convenient features both in analytical and numerical phases. A numerical example illustrating the usefulness of the method is included. Some numerical results are compared with experimental data. A full-wave analysis method for open microstrip structures T Itoh W Menzel Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 29, No. 1. (1981), pp. 63-68. 2008-06-11T20:18:23-00:00 1981 Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988] 29 1 63 68 analysis antenna microstrip http://www.citeulike.org/user/dcastro/article/2859756 <i>Antennas and Propagation, IEEE Transactions on, Vol. 55, No. 3. (2007), pp. 868-876.</i><br /><br />The analysis of resonant-type antennas based on the fundamental infinite wavelength supported by certain periodic structures is presented. Since the phase shift is zero for a unit-cell that supports an infinite wavelength, the physical size of the antenna can be arbitrary; the antenna's size is independent of the resonance phenomenon. The antenna's operational frequency depends only on its unit-cell and the antenna's physical size depends on the number of unit-cells. In particular, the unit-cell is based on the composite right/left-handed (CRLH) metamaterial transmission line (TL). It is shown that the CRLH TL is a general model for the required unit-cell, which includes a nonessential series capacitance for the generation of an infinite wavelength. The analysis and design of the required unit-cell is discussed based upon field distributions and dispersion diagrams. It is also shown that the supported infinite wavelength can be used to generate a monopolar radiation pattern. Infinite wavelength resonant antennas are realized with different number of unit-cells to demonstrate the infinite wavelength resonance Infinite Wavelength Resonant Antennas With Monopolar Radiation Pattern Based on Periodic Structures A Lai KMKH Leong T Itoh doi:10.1109/TAP.2007.891845 Antennas and Propagation, IEEE Transactions on, Vol. 55, No. 3. (2007), pp. 868-876. 2008-06-03T18:57:48-00:00 2007 Antennas and Propagation, IEEE Transactions on 55 3 868 876 antenna crlh metamaterial http://www.citeulike.org/user/dcastro/article/2839874 <i>Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 1 (2003), pp. 195-198 vol.1.</i><br /><br />This paper is composed of two parts. In the first part, the fundamentals of ideal transmission lines (TL) meta-materials (NM) with their physical characteristics and the synthesis of practical artificial TL-MMs with their circuital characteristics are presented. A microstrip implementation of a composite right/left handed (CRLH) TL is shown. In the second part, several novel applications based on the theory of the first part are demonstrated: a backfire-to-endfire leaky wave antenna, a coupled-line coupler with arbitrary coupling, a compact enhanced-bandwidth hybrid ring, a dual-band inharmonic branch-line coupler and a negative reflection/refraction phase-conjugating array interface. Novel microwave devices and structures based on the transmission line approach of meta-materials C Caloz T Itoh Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 1 (2003), pp. 195-198 vol.1. 2008-05-28T07:04:51-00:00 2003 Microwave Symposium Digest, 2003 IEEE MTT-S International 1 195 198 vol.1 devices metamaterial microwave tl http://www.citeulike.org/user/dcastro/article/2839871 <i>Microwave Conference, 2006. 36th European (2006), pp. 937-939.</i><br /><br />This paper reviews applications of the infinite wavelength supported by certain metamaterials accomplished to date by the authors' group. In particular, novel microwave resonators, dividers, and antennas based on the fundamental infinite wavelength supported by the composite right/left-handed metamaterial transmission line are presented. Applications and the unique properties of these novel microwave devices are also presented Applications of Infinite Wavelength Phenomenon A Lai KMKH Leong Tatsuo Itoh doi:10.1109/EUMC.2006.281075 Microwave Conference, 2006. 36th European (2006), pp. 937-939. 2008-05-28T07:02:30-00:00 2006 Microwave Conference, 2006. 36th European 937 939 metamaterial http://www.citeulike.org/user/dcastro/article/2839867 <i>Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 3B (2005), pp. 2-5 vol. 3B.</i><br /><br />A transmission matrix method (TMM), consisting of a 2D extension of 1D transmission matrix principles, is presented to compute the field distributions in 2D finite-size transmission line (TL) metamaterials (MMs) excited by an arbitrary source. This method, which is an MM generalization and extension of the method introduced by J.-H. Kim and M. Swaminathan (see IEEE Trans. Advanced Packag., vol.24, no.3, p.334-46, 2001) for packaged dense circuits, is a frequency-domain technique. Its main advantage is simplicity. A related, but more sophisticated, technique is the time-domain transmission line method (TLM), which was generalized for MMs by P.P.M. So and W.J.R. Hoefer (see IEEE MTT S Int. Microwave Symp. Dig., p.1779-82, 2004). Analysis 2D finite-size metamaterials by the transmission matrix method C Caloz Chi-Hyung Ahn T Itoh doi:10.1109/APS.2005.1552416 Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 3B (2005), pp. 2-5 vol. 3B. 2008-05-28T06:59:32-00:00 2005 Antennas and Propagation Society International Symposium, 2005 IEEE 3B 2 5 vol. 3B analysis metamaterial http://www.citeulike.org/user/dcastro/article/2839866 <i>Microwave Symposium Digest, 2005 IEEE MTT-S International (2005), 4 pp..</i><br /><br />A class-F power amplifier at 2.4GHz using a novel harmonic tuner based on a composite right/left handed (CRLH) transmission line (TL) is proposed and experimentally tested. Two structures are presented. One structure uses one open CRLH-TL stub to suppress 2nd, 3rd harmonics and the fundamental frequency is matched to 50/spl Omega/. The other structure uses two open CRLH-TL stubs in order to suppress 2nd, 3rd, 4th harmonics and the fundamental frequency is matched to specific impedance. The structure proposed is used to design a class-F power amplifier. A maximum drain efficiency of 64% is obtained. Class-F power amplifier using a multi-frequency composite right/left-handed transmission line harmonic tuner A Dupuy KMKH Leong T Itoh doi:10.1109/MWSYM.2005.1517142 Microwave Symposium Digest, 2005 IEEE MTT-S International (2005), 4 pp.. 2008-05-28T06:59:29-00:00 2005 Microwave Symposium Digest, 2005 IEEE MTT-S International 4 pp. amplifier crlh metamaterial power http://www.citeulike.org/user/dcastro/article/2839865 <i>Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 3A (2005), pp. 798-801 vol. 3A.</i><br /><br />An FDTD method, combined with thin wire and thin slot algorithms used to analyze a metamaterial based on periodic mushroom structures, is proposed. This proposed method is suitable for analyzing problems with fine structural details. Two examples of mushroom structures are investigated to compare the results between simulation and measurement to show left-handed propagation properties. Accuracy of the proposed method is verified compared to the measurement results. Efficient FDTD method for analysis of left-handed mushroom structure Wei-Yang Wu A Lai KMKH Leong Chih-Wen Kuo T Itoh doi:10.1109/APS.2005.1552377 Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 3A (2005), pp. 798-801 vol. 3A. 2008-05-28T06:58:07-00:00 2005 Antennas and Propagation Society International Symposium, 2005 IEEE 3A 798 801 vol. 3A crlh fdtd metamaterial mushroom http://www.citeulike.org/user/dcastro/article/2839856 <i>Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1423-1426.</i><br /><br />In this paper, a mode selective metamaterial which supports either forward or backward waves within the same frequency bandwidth is presented. The choice between dispersion operations is based on the mode excitation applied to the metamaterial. A demonstration microstrip prototype of this novel dual-mode composite right/left-handed metamaterial is realized and characterized. The metamaterial is right-handed under even-mode excitation and is left-handed under odd-mode excitation in the 1.86 GHz -2.00 GHz frequency range. Circuit simulations with the numerical and experimental results of the dual-mode metamaterial transmission line are performed to demonstrate electromagnetic wave steering and spatial multiplexing at a fixed frequency based on dispersion selectivity. Dual-Mode Metamaterial with Backward and Forward Wave Selectivity A Lai KMK Leong T Itoh doi:10.1109/MWSYM.2007.380499 Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1423-1426. 2008-05-28T06:51:03-00:00 2007 Microwave Symposium, 2007. IEEE/MTT-S International 1423 1426 metamaterial http://www.citeulike.org/user/dcastro/article/2839849 <i>Microwave Symposium Digest, 2005 IEEE MTT-S International (2005), 4 pp..</i><br /><br />A novel N-port series divider based on a composite right/left-handed (CRLH) transmission line (TL) supporting a wave with an infinite wavelength is presented. This novel divider evenly divides power in phase to an infinite number of ports at its infinite wavelength frequency. In addition, it is shown that the novel series divider's performance is not dependent on the location of its output ports. The basic operating principle is based on the fact that a CRLH TL is able to support a wave with an infinite wavelength. As a result, all points along the CRLH TL have the same magnitude and phase. A 3-port series divider consisting of a 8 unit-cell CRLH TL is shown to exhibit 0.22 dB maximum magnitude difference and 1.32/spl deg/ maximum phase difference between output ports at its infinite wavelength frequency. In addition, a 5-port series divider consisting of a 13 unit-cell CRLH TL is fabricated and shown to exhibit 0.30 dB maximum magnitude difference and 6.3/spl deg/ maximum phase difference between output ports at its infinite wavelength frequency. Both simulation and experimental results are shown to support the authors' claims. A novel N-port series divider using infinite wavelength phenomena A Lai KMKH Leong T Itoh doi:10.1109/MWSYM.2005.1516834 Microwave Symposium Digest, 2005 IEEE MTT-S International (2005), 4 pp.. 2008-05-28T06:43:47-00:00 2005 Microwave Symposium Digest, 2005 IEEE MTT-S International 4 pp. array metamaterial http://www.citeulike.org/user/dcastro/article/2839848 <i>Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 2B (2005), pp. 218-221 vol. 2B.</i><br /><br />The paper presents the design of an electrically small antenna employing a composite right/left-handed (CRLH) transmission line. The physical size and operating frequency of the antenna depend on the unit cell size and equivalent transmission line model parameters. Therefore, the small antenna is realized by miniaturizing the unit cell and increasing the shunt inductance and series capacitance. A four unit cell resonant antenna is designed and tested at 1.06 GHz. The length, width and height of the proposed antenna are (1/19)/spl lambda//sub 0/, (1/23)/spl lambda//sub 0/, and (1/83)/spl lambda//sub 0/, respectively. Design of resonant small antenna using composite right/left-handed transmission line Cheng-Jung Lee KMKH Leong T Itoh Antennas and Propagation Society International Symposium, 2005 IEEE, Vol. 2B (2005), pp. 218-221 vol. 2B. 2008-05-28T06:43:43-00:00 2005 Antennas and Propagation Society International Symposium, 2005 IEEE 2B 218 221 vol. 2B antenna crlh resonant small tl http://www.citeulike.org/user/dcastro/article/2839847 <i>Microwave Symposium Digest, 2006. IEEE MTT-S International (2006), pp. 935-938.</i><br /><br />This paper presents a methodology of designing a microwave bandstop filter and a bandpass filter by using a Composite Right/Left Handed transmission line (CRLH-TL) as part of a transversal filter. The CRLH-TL can be engineered to have specific phase slope and phase offset. Connecting the CRLH-TL and the conventional microstrip delay line at both input and output can establish a transversal filter where the signal merging at the output has broadband out of phase characteristics. Therefore, the bandstop filter can be created with signal rejection over a wide frequency range. The measured 3dB bandwidth of the bandstop filter is 130% and the minimum insertion loss at the next passband is ¿1.7dB. In addition, based on the bandstop filter a bandpass filter with a wide signal rejection range is developed by creating a frequency dependent defect in one branch of the bandstop filter. This is implemented by either attaching a microstrip open stub or capacitively coupling a microstrip resonator to the microstrip delay line. The 3dB passband bandwidth and the minimum insertion loss are 18%, ¿1.5dB and 8%, ¿2dB corresponding to the open stub and the resonator scheme, respectively. Metamaterial Transmission Line Based Bandstop and Bandpass Filter Designs Using Broadband Phase Cancellation Cheng-Jung Lee KMKH Leong Tatsuo Itoh doi:10.1109/MWSYM.2006.249870 Microwave Symposium Digest, 2006. IEEE MTT-S International (2006), pp. 935-938. 2008-05-28T06:43:41-00:00 2006 Microwave Symposium Digest, 2006. IEEE MTT-S International 935 938 filter metamaterial tl http://www.citeulike.org/user/dcastro/article/2839846 <i>Microwave Conference, 2006. APMC 2006. Asia-Pacific (2006), pp. 1060-1066.</i><br /><br />In this paper, a free space power combining oscillator antenna array using a metamaterial based injection locking coupling network is described and demonstrated. The unique metamaterial series coupling network utilizes the infinite wavelength phenomenon which allows it to support an infinitely long wave at a non-zero frequency. It is demonstrated that equal phase/amplitude oscillator synchronization can be achieved without regards to the antenna element spacing in the array. A small scale prototype oscillator array is designed to have compact, non-uniform element spacing to demonstrate the concept. An EIRP of 18 dBm at 2.37 GHz is measured. Power combining oscillator array using metamaterial based injection locking coupling network KMK Leong A Lai T Itoh doi:10.1109/APMC.2006.4429592 Microwave Conference, 2006. APMC 2006. Asia-Pacific (2006), pp. 1060-1066. 2008-05-28T06:43:38-00:00 2006 Microwave Conference, 2006. APMC 2006. Asia-Pacific 1060 1066 active array metamaterial oscillator http://www.citeulike.org/user/dcastro/article/2839828 <i>Antenna Technology Small Antennas and Novel Metamaterials, 2006 IEEE International Workshop on (2006), pp. 404-407.</i> Composite Right/Left-Handed Metamaterial Antennas A Lai KMKH Leong T Itoh Antenna Technology Small Antennas and Novel Metamaterials, 2006 IEEE International Workshop on (2006), pp. 404-407. 2008-05-28T06:41:50-00:00 2006 Antenna Technology Small Antennas and Novel Metamaterials, 2006 IEEE International Workshop on 404 407 antenna crlh metamaterial http://www.citeulike.org/user/dcastro/article/2839827 <i>Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1745-1748.</i><br /><br />This paper presents a broadband quadrature hybrid which makes use of the broadband power division properties of conventional Wilkinson power splitters along with broadband phase difference achieved using metamaterial based delay lines. The bandwidth of the 90degplusmn5deg phase difference and 0.48 dB power difference between the outputs of the Wilkinson power splitter and metamaterial delay line combination is 67%. The full four-port coupler is formed employing an additional combiner. A phase/power difference between the hybrid outputs of 90degplusmn10deg and 1.2 dB, respectively, are observed over the same 67% bandwidth. To demonstrate the applicability of the proposed broadband quadrature hybrid, a continuous phase shifter which is based on the vector sum method is tested. Broadband Quadrature Hybrid Design Using Metamaterial Transmission Line and Its Application in the Broadband Continuous Phase Shifter Cheng-Jung Lee KMKH Leong T Itoh doi:10.1109/MWSYM.2007.380066 Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1745-1748. 2008-05-28T06:41:48-00:00 2007 Microwave Symposium, 2007. IEEE/MTT-S International 1745 1748 broadband crlh metamaterial tl http://www.citeulike.org/user/dcastro/article/2839826 <i>Microwave Symposium Digest, 2006. IEEE MTT-S International (2006), pp. 931-934.</i><br /><br />In this paper, dual-band bandpass and bandstop filters using composite right/left-handed (CRLH) metamaterial transmission lines (TLs) are developed. The conventional bandpass and bandstop filters are first designed using quarter-wave short-circuited and open-circuited stubs, respectively. Then the dual-band filters with arbitrary dual operating bands can then be easily implemented by replacing the microstrip lines with the CRLH TLs. The dual-band bandpass and bandstop filters using the CRLH TLs are experimentally demonstrated at dual operating frequencies 1 GHz and 1.9 GHz. The measured results are in a good agreement with the simulated results. From the measured performances, the dual-band bandpass filter has 29.8% and 17.3% pass bandwidths, while the dual-band bandstop filter has 12.2% and 6.9% stop bandwidths with 30dB attenuation Dual-Band Bandpass and Bandstop Filters Using Composite Right/Left-Handed Metamaterial Transmission Lines Chao-Hsiung Tseng Tatsuo Itoh doi:10.1109/MWSYM.2006.249869 Microwave Symposium Digest, 2006. IEEE MTT-S International (2006), pp. 931-934. 2008-05-28T06:41:46-00:00 2006 Microwave Symposium Digest, 2006. IEEE MTT-S International 931 934 crlh filter metamaterial http://www.citeulike.org/user/dcastro/article/2839824 <i>Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1823-1826.</i><br /><br />A new configuration of composite right/left handed (CRLH) metamaterial structure is proposed, which comprises of TE-resonant dielectric resonators and metallic parallel mesh plates. The balanced CRLH transmission lines are designed by adjusting the optimal distance between the mesh plates for a given size of the mesh windows. To confirm the fundamental operation, the transmission and far field radiation characteristics are simulated and measured for the one-dimensional structure. The numerical results show that the increase in the thickness of metallic mesh plates dramatically reduces the radiation efficiency. Nevertheless, the numerical simulation and measurement validate the continuous change in the phase flow along the waveguide from backward to forward directions with the operational frequency. Composite Right/Left Handed Metamaterial Structures Composed of Dielectric Resonators and Parallel Mesh Plates T Ueda N Michishita T Itoh doi:10.1109/MWSYM.2007.380104 Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1823-1826. 2008-05-28T06:41:40-00:00 2007 Microwave Symposium, 2007. IEEE/MTT-S International 1823 1826 crlh metamaterial resonator http://www.citeulike.org/user/dcastro/article/2839825 <i>Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1623-1626.</i><br /><br />Metamaterial-based composite right/left-handed transmission lines are used in the design of fixed frequency and tunable ring resonators. Under specific design conditions, the first two resonant modes can be narrowly spaced. A simple passive band-pass filter is demonstrated at 2.92 GHz with a bandwidth of about 9% using this concept. This type of design is also used as a tunable resonator and a tuning range of 30% is demonstrated. Fixed Frequency and Tunable Metamaterial-Based Ring Resonators with Narrowly Spaced Resonances CA Allen KMK Leong T Itoh doi:10.1109/MWSYM.2007.379997 Microwave Symposium, 2007. IEEE/MTT-S International (2007), pp. 1623-1626. 2008-05-28T06:41:40-00:00 2007 Microwave Symposium, 2007. IEEE/MTT-S International 1623 1626 metamaterial resonator ring http://www.citeulike.org/user/dcastro/article/2839810 <i>Antenna Technology: Small Antennas and Novel Metamaterials, 2005. IWAT 2005. IEEE International Workshop on (2005), pp. 69-72.</i><br /><br />Recent research on metamaterials with simultaneously negative permittivity (/spl epsiv/) and permeability (/spl mu/), more commonly referred to as left-handed (LH) materials, has stimulated the development of novel concepts and applications. Since right-handed (RH) effects are unavoidable, practical LH materials (LHM) are in reality composite right/left-handed (CRLH) materials. Interestingly, the co-existence of LH and RH contributions in CRLH materials, far from being detrimental, leads to useful phenomena. By applying a transmission-line (TL) approach towards CRLH metamaterials, the unique properties of these metamaterials have been used to realize novel microwave devices including antennas with characteristics (functionalities or performance) surpassing those of conventional (i.e., RH) materials. Microwave devices based on composite right/left-handed (CRLH) transmission line metamaterials A Lai C Caloz T Itoh doi:10.1109/IWAT.2005.1461003 Antenna Technology: Small Antennas and Novel Metamaterials, 2005. IWAT 2005. IEEE International Workshop on (2005), pp. 69-72. 2008-05-28T06:41:03-00:00 2005 Antenna Technology: Small Antennas and Novel Metamaterials, 2005. IWAT 2005. IEEE International Workshop on 69 72 crlh metamaterial microwave tl http://www.citeulike.org/user/dcastro/article/2809071 <i>Antennas and Propagation Society International Symposium 2006, IEEE (2006), pp. 394-397.</i><br /><br />Application of left-handed (LH) metamaterials in the field of microwave engineering has grown rapidly following their experimental verification. In particular, the LH transmission line (TL) has been used to realize various microwave devices not possible with conventional TLs alone. The purpose of this paper is to summarize some of the recent advances in microwave devices based on LH TLs. In particular, devices based on the unique characteristics of the composite right/left-handed (CRLH) TL, which is the general model of a practical LH TL, are presented. Microwave devices based on left-handed transmission lines A Lai KMKH Leong T Itoh doi:10.1109/APS.2006.1710541 Antennas and Propagation Society International Symposium 2006, IEEE (2006), pp. 394-397. 2008-05-18T14:06:55-00:00 2006 Antennas and Propagation Society International Symposium 2006, IEEE 394 397 crlh lh metamaterial microwave tl http://www.citeulike.org/user/dcastro/article/2801966 <i>Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 2 (1999), pp. 655-658 vol.2.</i><br /><br />A novel retrodirective array with intrinsic gain has been developed and demonstrated successfully for the first time. Each heterodyne scattering element employs a balanced FET mixer, which provides effective isolation between RF and IF signals with identical frequencies to realize phase conjugation. A 4-element array has been fabricated, which demonstrated excellent retrodirectivity A retrodirective array using balanced quasi-optical FET mixers with conversion gain RY Miyamoto Yongxi Qian T Itoh doi:10.1109/MWSYM.1999.779846 Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 2 (1999), pp. 655-658 vol.2. 2008-05-15T15:11:14-00:00 1999 Microwave Symposium Digest, 1999 IEEE MTT-S International 2 655 658 vol.2 array fet gain mixer http://www.citeulike.org/user/dcastro/article/2801486 <i>Microwave Symposium Digest, 1996., IEEE MTT-S International, Vol. 2 (1996), pp. 651-653 vol.2.</i><br /><br />Design and performance of a new transmit/receive (T/R) antenna switch for mobile communication systems at 1.8 GHz using Si/SiGe Heterojunction Bipolar Transistors (HBT) are described. The switch is designed to be a part of a transceiver front end for DECT and DCS 1800 applications. This circuit requires no external DC bias. The insertion loss in the receive arm is <1.5 dB and the isolation >25 dB at the operating frequency Zero power consumption Si/SiGe HBT SPDT T/R antenna switch R Gotzfried T Itoh JF Luy H Schumacher doi:10.1109/MWSYM.1996.511024 Microwave Symposium Digest, 1996., IEEE MTT-S International, Vol. 2 (1996), pp. 651-653 vol.2. 2008-05-15T12:22:27-00:00 1996 Microwave Symposium Digest, 1996., IEEE MTT-S International 2 651 653 vol.2 antenna transceiver http://www.citeulike.org/user/dcastro/article/2801488 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 44, No. 2. (1996), pp. 326-330.</i><br /><br />With the advance of high speed laser technology, optical interaction with microwave circuits has become highly viable. Such interaction is advantageous as the fiber is low-loss, lightweight, and immune to electromagnetic interference. In this paper, interaction of direct-modulated and gain-switched optical links with active antenna phased array systems is demonstrated. In the direct-modulated optical system, the RF signal directly modulates the DFB laser. In the gain-switched optical system, the laser is gain-switched to function as a RF frequency doubler. The modulated signal is transmitted via an optical fiber and recovered at the receiving end by a high-speed photodetector. The recovered RF is then injected into the active antenna phased array systems as an injection-locking reference signal. Two active antenna systems are used for this demonstration: beam-switching and Doppler transceiver Use of direct-modulated/gain-switched optical links in monopulse-type active phased array systems Siou Chew DTK Tong MC Wu T Itoh doi:10.1109/22.481583 Microwave Theory and Techniques, IEEE Transactions on, Vol. 44, No. 2. (1996), pp. 326-330. 2008-05-15T12:22:28-00:00 1996 Microwave Theory and Techniques, IEEE Transactions on 44 2 326 330 active array phased http://www.citeulike.org/user/dcastro/article/2801487 <i>Microwave Conference Proceedings, 1993. APMC '93., 1993 Asia-Pacific, Vol. 1 (1993), pp. 1-5-1-8 vol.1.</i><br /><br />The authors describe a design method and experimental results of a uniplanar active integrated antenna with tuning stub. The circuit consists of a slot radiator, an FET oscillator and CPWs. The active integrated antenna oscillated at 7.77 GHz and its oscillation frequency was tuned to 7.94 GHz by cutting the tuning stub. The maximum tuning range due to change of the drain voltage was 70 MHz. No significant change on antenna pattern measurement was observed Uniplanar active integrated antenna element with tuning stub using an FET and CPW's S Kawasaki T Itoh doi:10.1109/APMC.1993.468477 Microwave Conference Proceedings, 1993. APMC '93., 1993 Asia-Pacific, Vol. 1 (1993), pp. 1-5-1-8 vol.1. 2008-05-15T12:22:28-00:00 1993 Microwave Conference Proceedings, 1993. APMC '93., 1993 Asia-Pacific 1 1-5 1-8 vol.1 active antenna fet integrated planar http://www.citeulike.org/user/dcastro/article/2801483 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 42, No. 4. (1994), pp. 734-741.</i><br /><br />Two-dimensional quasi-optical power-combining arrays are designed by using strongly coupled oscillators. The oscillators are connected by a microstrip coupling line for strong coupling. Two types of connections are discussed. One is the line-structure and the other is the loop-structure. The oscillation modes of the coupled oscillators for these two types of configurations are analyzed and compared. The experimental results for circuits with different configurations are compared to the theoretical results. The application of these two types of connections in the two-dimensional array is discussed. A multilayer (3-D) structure is employed in the circuit design to accommodate the complex layout of the two-dimensional arrays. A 4×4 power-combining array in multilayer structure is demonstrated Two-dimensional quasi-optical power-combining arrays using strongly coupled oscillators J Lin T Itoh doi:10.1109/22.285088 Microwave Theory and Techniques, IEEE Transactions on, Vol. 42, No. 4. (1994), pp. 734-741. 2008-05-15T12:21:02-00:00 1994 Microwave Theory and Techniques, IEEE Transactions on 42 4 734 741 array oscillator http://www.citeulike.org/user/dcastro/article/2801482 <i>Millimeter Waves, 1997 Topical Symposium on (1997), pp. 137-140.</i><br /><br />This paper presents FDTD simulation and measurement results for a microstrip-fed Yagi-Uda slot array antenna used for surface wave excitation of a dielectric slab. Parameters investigated are input return loss, surface wave field profiles, front-to-back ratio and mutual coupling. The FDTD simulation not only confirms the design philosophy of our planar dielectric quasi-optical (PDQ) power combiner, but also provides a powerful CAD tool for its practical design and optimization at millimeter wavelengths Surface wave excitation of a dielectric slab by a Yagi-Uda slot array antenna-FDTD simulation and measurement Yongxi Qian AR Perkons T Itoh doi:10.1109/TSMW.1997.702490 Millimeter Waves, 1997 Topical Symposium on (1997), pp. 137-140. 2008-05-15T12:21:01-00:00 1997 Millimeter Waves, 1997 Topical Symposium on 137 140 array fdtd measurement simulation surface wave http://www.citeulike.org/user/dcastro/article/2801478 <i>Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1541-1544 vol.3.</i><br /><br />In this paper, an antenna array system with self-calibration capability to the antenna element position errors is proposed. The essential concept of self-calibration is to detect the element positions by using near field reference sources. The estimated position information is further substituted into the beamforming process to correct the distorted pattern of the antenna array. To validate the proposed concept, a test bed with a "distorted" eight element array is set up. With the proposed calibration architecture, the estimation of the position errors is within 7% of the free space wavelength. Based on the estimation information, the array pattern can thus be synthesized. A self-calibration antenna array system with moving apertures Weijun Yao Yuanxun Wang T Itoh Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1541-1544 vol.3. 2008-05-15T12:19:03-00:00 2003 Microwave Symposium Digest, 2003 IEEE MTT-S International 3 1541 1544 vol.3 antenna array http://www.citeulike.org/user/dcastro/article/2801477 <i>Antennas and Propagation Society International Symposium, 1998. IEEE, Vol. 2 (1998), pp. 656-659 vol.2.</i><br /><br />A periodically loaded substrate is employed to reduce excitation of surface waves by a patch antenna. The computed dispersion diagram of the substrates shows that surface wave propagation is forbidden along specific directions. By properly orienting the patch antenna on the substrate, this can result in good improvement of antenna performance. In agreement with the expected result, the measured radiation pattern shows a 10 dB reduction in the side lobes associated with power launched from surface waves Radiation characteristics of a patch antenna on a thin PBG substrate R Coccioli WR Deal T Itoh doi:10.1109/APS.1998.702023 Antennas and Propagation Society International Symposium, 1998. IEEE, Vol. 2 (1998), pp. 656-659 vol.2. 2008-05-15T12:19:03-00:00 1998 Antennas and Propagation Society International Symposium, 1998. IEEE 2 656 659 vol.2 antenna patch pbg http://www.citeulike.org/user/dcastro/article/2801476 <i>Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. (1990), pp. 799-802 vol.2.</i><br /><br />A traveling wave antenna array with the crosstie-overlay slow-wave structures serving as the transmission lines is described. The measured radiation pattern is shown to agree with the calculated radiation pattern, and the frequency-scanning feature is also demonstrated. Due to the slow-wave transmission lines and the integrated design of the feed structure and the radiating elements, this antenna is quite suitable for monolithic microwave integrated circuits Physically-small frequency scanning antenna YD Lin T Itoh doi:10.1109/APS.1990.115229 Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. (1990), pp. 799-802 vol.2. 2008-05-15T12:18:59-00:00 1990 Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. 799 802 vol.2 antenna small http://www.citeulike.org/user/dcastro/article/2801475 <i>Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1616-1619 vol.3.</i><br /><br />The authors report the design and experimental data of a prototype of an optically controlled uniplanar active integrated antenna array. The active antenna circuit consists of two negative-resistance oscillators with two slots. As the transmission line, the CPW (coplanar waveguide) is used to realize the uniplanar active antenna array. The tuning of operating frequencies was carried out by illumination. Measured antenna patterns are presented. An optical tuning range of 70 MHz around 8.8 GHz was obtained Optical control on 2-element CPW active integrated antenna array with strong coupling S Kawasaki T Itoh doi:10.1109/APS.1993.385507 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1616-1619 vol.3. 2008-05-15T12:18:44-00:00 1993 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest 1616 1619 vol.3 active array coupling integrated http://www.citeulike.org/user/dcastro/article/2801467 <i>Potentials, IEEE, Vol. 22, No. 3. (2003), pp. 16-21.</i><br /><br />Antenna arrays are individual radiating elements combined so that they function and perform like a single large antenna. Besides high radiating beam directionality, antenna arrays offer the capability to scan the main beam and control sidelobe radiation electronically. Retrodirective antenna arrays, as the name suggests, have a special feature. When receiving a signal from an unspecified direction, the array can automatically transmit a signal response to that same direction without any previous knowledge of the source direction. This function is performed automatically without the use of phase-shifters or digital circuitry. Compared to other array antennas that rely on digital signal processing (DSP) for beam direction control, this approach is much simpler and potentially faster because digital calculation is not needed. The automatic beam control nature of retrodirective arrays is well suited for RFID (radio frequency identification) and microwave tracking beacon applications. The article discusses the basic functionality as well as the ongoing research efforts and developments in retrodirective array architectures. Self-phasing attributes of different arrays are presented, as well as their applicability in practical communication systems. Moving forward in retrodirective antenna arrays KMKH Leong RY Miyamoto T Itoh doi:10.1109/MP.2003.1232308 Potentials, IEEE, Vol. 22, No. 3. (2003), pp. 16-21. 2008-05-15T12:15:00-00:00 2003 Potentials, IEEE 22 3 16 21 antenna array http://www.citeulike.org/user/dcastro/article/2801465 <i>Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 664-667 vol.2.</i><br /><br />A theory based on the average potential method is presented to explain this phenomenon. The analysis of the stable modes shows that it is possible to control the mode by suitable design of the circuit. This active antenna array generates the sum pattern when the two units are connected by a metal strip. Instead of the chip resistor and the metal strip, appropriate devices may be used in the circuit to switch the modes and the radiation pattern can be changed electronically Mode switch in a two-element active array J Lin T Itoh S Nogi doi:10.1109/APS.1993.385259 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 664-667 vol.2. 2008-05-15T12:14:47-00:00 1993 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest 664 667 vol.2 active array http://www.citeulike.org/user/dcastro/article/2801464 <i>Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. (1990), pp. 788-790 vol.2.</i><br /><br />A twin slot antenna fed by a microstrip line for the millimeter-wave/far-infrared range is investigated. The twin slots couple incident power into a microstrip feed line which consists of microstrip low-pass filters and a microbolometer detector. An advantage of this structure is that the feed lines are isolated from the incident radiation by the slot ground plane. Several antennas were built and tested between 90 and 94 GHz. Measurements are compared with theory for the twin slots on a quartz-air-quartz stack at 90.5 GHz. Although the shape of the beam patterns agrees closely with theory, the measured gain is about 10 dB less than calculated. This discrepancy exists because the theory does not account for the various losses. It is noted that it should be possible to obtain better beam patterns by using GaAs as the outer dielectric instead of quartz MM wave/FIR twin slot antenna structures JG Heston SM Wentworth RL Rogers DP Neikirk T Itoh doi:10.1109/APS.1990.115226 Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. (1990), pp. 788-790 vol.2. 2008-05-15T12:14:43-00:00 1990 Antennas and Propagation Society International Symposium, 1990. AP-S. Merging Technologies for the 90's. Digest. 788 790 vol.2 antenna http://www.citeulike.org/user/dcastro/article/2801466 <i>Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 2 (2002), pp. 1277-1280.</i><br /><br />A compact quadrature modulator/demodulator integrated with a 40 GHz patch antenna for millimeter wave wireless applications is proposed. Anti-parallel diode sub-harmonic mixers are constructed for broad-band direct quadrature conversion. Overall phase and amplitude imbalance between the mixer I and Q output channels are less than 1.2° and 1 dB respectively. An average conversion loss of mixers of -14.6 dB is achieved in the frequency range from 39.75 GHz to 40.25 GHz. A communication link is built based on a pair of the proposed front-ends. Data transmission at up to 1 Gb/s data rate for QPSK modulation is successfully demonstrated Millimeter wave direct quadrature converter integrated with antenna for broad-band wireless communications Ji-Yong Park Seong-Sik Jeon Yuanxun Wang T Itoh doi:10.1109/MWSYM.2002.1011896 Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 2 (2002), pp. 1277-1280. 2008-05-15T12:14:54-00:00 2002 Microwave Symposium Digest, 2002 IEEE MTT-S International 2 1277 1280 antenna broadband converter mixer wireless http://www.citeulike.org/user/dcastro/article/2801463 <i>Electronics Letters, Vol. 34, No. 23. (1998), pp. 2194-2196.</i><br /><br />A compact and uniplanar antenna with broadband characteristics is presented. The novel Yagi-like printed dipole array antenna is fed by a microstrip-to-coplanar strip transition, and uses the truncated microstrip ground plane as its reflecting element. An X-band prototype measures a bandwidth of 17%. With 6.5 dB gain, 18 dB front-to-back ratio, and lower than -15 dB cross-polarisation level at 10 GHz Microstrip-fed quasi-Yagi antenna with broadband characteristics Y Qian WR Deal N Kaneda T Itoh Electronics Letters, Vol. 34, No. 23. (1998), pp. 2194-2196. 2008-05-15T12:14:41-00:00 1998 Electronics Letters 34 23 2194 2196 antenna broadband microstrip http://www.citeulike.org/user/dcastro/article/2801462 <i>Antennas and Propagation Society International Symposium, 2003. IEEE, Vol. 1 (2003), pp. 416-419 vol.1.</i><br /><br />The paper, dedicated to the memory of Professor Y.T. Lo, describes two research projects that vividly remind me of his influence as well as my interactions with him which I cheerfully remember. These projects are the microstrip disk resonator and meta-material research. Electromagnetic insight of Professor Y.T. Lo and his influence on my research career Tatsuo Itoh Antennas and Propagation Society International Symposium, 2003. IEEE, Vol. 1 (2003), pp. 416-419 vol.1. 2008-05-15T12:14:38-00:00 2003 Antennas and Propagation Society International Symposium, 2003. IEEE 1 416 419 vol.1 metamaterial overview http://www.citeulike.org/user/dcastro/article/2801461 <i>Antennas and Propagation, IEEE Transactions on, Vol. 51, No. 4. (2003), pp. 756-765.</i><br /><br />We present the analysis and design of a microstrip antenna array with a conical beam. The antenna array employs a periodic structure derived from a microstrip on a perforated ground plane. The microstrip antenna array consists of eight leaky lines evenly distributed around a circle. Each line radiates mainly a pair of forward and backward beams, forming a conical beam. The new leaky line design employs the concept of space-harmonic modulation on the EH/sub 0/ mode launched at the common joint of the antenna array. The scattering and dispersion characteristics of the leaky line are thoroughly investigated. It is theoretically and experimentally validated that the perturbation of the photolithographically etched antisymmetric holes excites the leaky EH/sub 1/ mode. Scattering analyses of the surface currents on the microstrip reveal in detail the physical operation of the leaky line. The dispersion characteristics are, thus, established and shown in a Brillouin diagram, indicating the role of each space harmonic, denoted by its complex propagation constant, /spl gamma//sub m,n//sup /spl plusmn//. Constant /spl gamma//sub m,n//sup /spl plusmn// represents a traveling-wave component of the nth higher-order spatial component in association with the EH/sub m/ mode: the superscript, + (-), signifies a forward (backward) traveling wave. For the particular leaky line design, /spl gamma//sub 0,-1//sup +/ and /spl gamma//sub 1,0//sup +/ space harmonics, both showing odd-symmetric field polarization, and both outside the triangular Brillouin region, form the backward and forward leaky waves, respectively. When the leaky lines are evenly and collinearly tied, an 11.5 GHz radial antenna array prototype is formed, and emits a conical beam, showing a 3 dB beamwidth of 24/spl deg/ at the flare angle of 31/spl deg/. A periodic microstrip radial antenna array with a conical beam Kuo-Cheng Chen Yongxi Qian CKC Tzuang T Itoh doi:10.1109/TAP.2003.811064 Antennas and Propagation, IEEE Transactions on, Vol. 51, No. 4. (2003), pp. 756-765. 2008-05-15T12:14:36-00:00 2003 Antennas and Propagation, IEEE Transactions on 51 4 756 765 antenna array microstrip periodic http://www.citeulike.org/user/dcastro/article/2801458 <i>Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1677-1680 vol.3.</i><br /><br />A 60 GHz integrated four-element planar antenna array is developed. Each antenna is integrated with a sub-harmonic I/Q mixer based on APDPs for the convenience of high-speed signal processing such as adaptive beamforming. An average conversion loss of four channels of less than 10.6 dB is achieved. Amplitude imbalance and phase deviation between I and Q outputs of each channel are less than 2.5 dB and 7/spl deg/, respectively. The array is used to construct a digital beamforming system along with an IF circuit block and DSP modules. Beam scanning results are successfully demonstrated. A 60 GHz integrated antenna array for high-speed digital beamforming applications Ji-Yong Park Yuanxun Wang T Itoh Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1677-1680 vol.3. 2008-05-15T12:12:54-00:00 2003 Microwave Symposium Digest, 2003 IEEE MTT-S International 3 1677 1680 vol.3 active antenna array beamformer integrated http://www.citeulike.org/user/dcastro/article/2801457 <i>Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 4 (2002), pp. 562-565 vol.4.</i><br /><br />Both K-band (20 GHz) and Q-band (44 GHz) passive linear arrays using quasi-Yagi antenna elements are presented. No scan-blindness is observed when the beam is steered 55 degrees from broadside for an inter-element spacing of 0.4/spl lambda/ at X-band. Broad bandwidth of 50% is observed at X-band while both K and Q-band arrays demonstrate over 30% bandwidth (VSWR<2). Measured radiation patterns in four-element linear arrays show well-defined endfire main beams with first sidelobe levels better than -12 dB, cross polarization levels better than -15 dB, and array gains of 8-10 dB across the entire operating band. High performance K- and Q-band quasi-Yagi linear arrays T Nishio Y Wang Y Qian T Itoh doi:10.1109/APS.2002.1017047 Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 4 (2002), pp. 562-565 vol.4. 2008-05-15T12:12:50-00:00 2002 Antennas and Propagation Society International Symposium, 2002. IEEE 4 562 565 vol.4 array http://www.citeulike.org/user/dcastro/article/2801456 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 1135-1138 vol.2.</i><br /><br />The global time-domain nonlinear analysis of microwave FET oscillators and self-oscillating mixers using the extended FDTD technique is presented. Employing the concept of equivalent current/voltage sources, the device-wave interaction is characterized and incorporated into the FDTD time-stepping algorithm. Consequently, investigation of highly nonlinear phenomena, such as injection locking and intermodulation, can be accomplished by utilizing a large-signal device circuit model. Theoretical results are validated by experiments Global time-domain full-wave analysis of microwave FET oscillators and self-oscillating mixers Min Chen WR Deal B Houshmand T Itoh doi:10.1109/MWSYM.1998.705194 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 1135-1138 vol.2. 2008-05-15T12:12:47-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 2 1135 1138 vol.2 fet microwave mixer oscillator http://www.citeulike.org/user/dcastro/article/2801455 <i>Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters], Vol. 6, No. 8. (1996), 280.</i><br /><br />Connecting several tunneling diodes-resonant tunneling diodes (RTD's) or tunnel diodes-in series has been shown to be a feasible method for increasing the output power and stability of oscillator circuits using these devices. However, such oscillators require special means of triggering due to biasing difficulties associated with their dc instability. RF triggering was proven to be an effective method of initiating such an oscillation in one-port circuits. An experimental demonstration of free-space RF triggering of an active antenna with a series connection is described here. Active antenna circuits offer excellent isolation between the triggering and oscillation signals and a favorable configuration for spatial power-combining arrays Free-space RF triggering of an active antenna with series-connected tunneling diodes O Boric-Lubecke Dee-Son Pan T Itoh doi:10.1109/75.508553 Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters], Vol. 6, No. 8. (1996), 280. 2008-05-15T12:11:22-00:00 1996 Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters] 6 8 280 active antenna http://www.citeulike.org/user/dcastro/article/2801453 <i>Antennas and Propagation, IEEE Transactions on, Vol. 45, No. 8. (1997), pp. 1294-1301.</i><br /><br />The finite-difference time-domain (FDTD) method is used to analyze a dielectric leaky-wave antenna comprising metal strips etched on a rectangular dielectric rod. The radiation patterns of the leaky-wave antenna with and without the transition are determined by using FDTD. The effects of the launching discontinuity on the performance of the antenna are discussed. In addition, the application of the perfectly matched layer (PML) technique to the three-dimensional (3-D) dielectric waveguide and its performance, compared to those of the Mur's (1981) first-order and super-absorbing Mur's first-order absorbing boundary conditions (ABCs) are described. In addition, the effects caused by perturbation on the wave propagation characteristics of dielectric waveguide are also discussed. The FDTD results are verified by a W-band experiment and found to be in good agreement FDTD analysis of a metal-strip-loaded dielectric leaky-wave antenna M Chen B Houshmand T Itoh doi:10.1109/8.611250 Antennas and Propagation, IEEE Transactions on, Vol. 45, No. 8. (1997), pp. 1294-1301. 2008-05-15T12:11:18-00:00 1997 Antennas and Propagation, IEEE Transactions on 45 8 1294 1301 analysis antenna fdtd leaky http://www.citeulike.org/user/dcastro/article/2801452 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 43, No. 2. (1995), pp. 267-271.</i><br /><br />The performance of a spatial power-combining array with device failure is investigated. Experimental results show that the array still combines the power in the broadside direction when the DC open-circuit failure occurs. Analysis of measured radiation patterns indicated that the power radiated from the patch antenna attached to the failed device is much smaller than the power radiated from other patch antennas. The effects of the chip resistor and the RF impedance of failed device are discussed Experiments of device failures in a spatial power-combining array Jenshan Lin T Itoh doi:10.1109/22.348083 Microwave Theory and Techniques, IEEE Transactions on, Vol. 43, No. 2. (1995), pp. 267-271. 2008-05-15T12:11:15-00:00 1995 Microwave Theory and Techniques, IEEE Transactions on 43 2 267 271 array combining power http://www.citeulike.org/user/dcastro/article/2801451 <i>Microwave Symposium Digest, 1994., IEEE MTT-S International (1994), pp. 883-886 vol.2.</i><br /><br />The FDTD algorithm is used to simulate a two element active antenna which is capable of three different coupled oscillation modes. This analysis correctly predicts which modes will be stable in the steady state under different loading conditions. The predicted oscillation modes, oscillation frequencies and radiation patterns are compared with experimental data Electromagnetic simulation of mode control of a two element active antenna B Toland J Lin B Houshmand T Itoh doi:10.1109/MWSYM.1994.335216 Microwave Symposium Digest, 1994., IEEE MTT-S International (1994), pp. 883-886 vol.2. 2008-05-15T12:11:08-00:00 1994 Microwave Symposium Digest, 1994., IEEE MTT-S International 883 886 vol.2 active antenna array simulation http://www.citeulike.org/user/dcastro/article/2801446 <i>Antennas and Propagation, IEEE Transactions on, Vol. 46, No. 11. (1998), pp. 1665-1673.</i><br /><br />The design and fabrication of a leaky-wave antenna at 212 GHz with a dielectric waveguide as the guiding structure is described and some measured results are presented. At this frequency, previously reported approaches for fabricating such an antenna present certain difficulties, which have been overcome using some innovations. This antenna is expected to be useful for radiometry and, consequently should have small beamwidth, high efficiency, and large beam scanning with frequency. It is shown how these can be achieved Dielectric waveguide-based leaky-wave antenna at 212 GHz A Basu T Itoh doi:10.1109/8.736619 Antennas and Propagation, IEEE Transactions on, Vol. 46, No. 11. (1998), pp. 1665-1673. 2008-05-15T12:09:49-00:00 1998 Antennas and Propagation, IEEE Transactions on 46 11 1665 1673 antenna leaky http://www.citeulike.org/user/dcastro/article/2801445 <i>Electronics Letters, Vol. 36, No. 1. (2000), pp. 1-2.</i><br /><br />A novel coplanar waveguide fed quasi-Yagi antenna is presented. A wide bandwidth is achieved by using a broadband coplanar waveguide to a slotline balun. An X-band prototype has been realised which demonstrates a broad bandwidth (30%), -19 dB front-to-back ratio, and cross-polarisation better than -17 dB at 10 GHz. Coplanar waveguide fed quasi-Yagi antenna J Sor Yongxi Qian T Itoh doi:10.1049/el:20000132 Electronics Letters, Vol. 36, No. 1. (2000), pp. 1-2. 2008-05-15T12:09:44-00:00 2000 Electronics Letters 36 1 1 2 antenna coplanar http://www.citeulike.org/user/dcastro/article/2801444 <i>Microwave Symposium Digest, 1997., IEEE MTT-S International, Vol. 2 (1997), pp. 687-690 vol.2.</i><br /><br />A high efficiency class F power amplifier integrated with a circular sector microstrip antenna is reported. To obtain the class F operation, the second and third harmonics are shaped through the input impedance of the antenna. At the operating frequency of 2.55 GHz, a power added efficiency of 63% is demonstrated Class F power amplifier integrated with circular sector microstrip antenna V Radisic Yongxi Qian T Itoh doi:10.1109/MWSYM.1997.602884 Microwave Symposium Digest, 1997., IEEE MTT-S International, Vol. 2 (1997), pp. 687-690 vol.2. 2008-05-15T12:09:43-00:00 1997 Microwave Symposium Digest, 1997., IEEE MTT-S International 2 687 690 vol.2 amplifier antenna circular integrated microstrip power http://www.citeulike.org/user/dcastro/article/2801443 <i>Microwave Symposium Digest, 1997., IEEE MTT-S International, Vol. 3 (1997), pp. 1623-1626 vol.3.</i><br /><br />Mutual coupling between both single and twin slot antennas fed by non-leaky coplanar (NLC) waveguides with conductor backing is characterized rigorously for the first time. While there is pronounced mutual coupling (about -12 dB) between two single slots separated by λ₀/2, we show that by employing an optimized twin-slot configuration, it is possible to reduce significantly the coupling level to below -30 dB over a 15% bandwidth, making this unidirectional radiator an attractive candidate for millimeter-wave imaging arrays Characterization and minimization of mutual coupling between NLC-FED slot antennas Yongxi Qian T Itoh doi:10.1109/MWSYM.1997.596682 Microwave Symposium Digest, 1997., IEEE MTT-S International, Vol. 3 (1997), pp. 1623-1626 vol.3. 2008-05-15T12:09:38-00:00 1997 Microwave Symposium Digest, 1997., IEEE MTT-S International 3 1623 1626 vol.3 antenna array coupling mutual http://www.citeulike.org/user/dcastro/article/2801442 <i>Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 4 (1999), pp. 1409-1411 vol.4.</i><br /><br />A C-band direct conversion receiver front-end based on a resistive FET mixer has been developed. Resistive FET mixers, as opposed to other configurations, require only gate bias and no drain bias. Thus the baseband signal can be easily filtered from the drain terminal. The resistive FET mixer is integrated with rectangular microstrip patch antenna, yielding a compact receiver front-end. A prototype was constructed and demonstrated satisfactory demodulation of a BPSK modulated RF signal C-band direct conversion receiver front-end using a resistive FET mixer S Lin Yongxi Qian T Itoh doi:10.1109/MWSYM.1999.780213 Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 4 (1999), pp. 1409-1411 vol.4. 2008-05-15T12:09:03-00:00 1999 Microwave Symposium Digest, 1999 IEEE MTT-S International 4 1409 1411 vol.4 c-band conversion direct fet front-end mixer receiver resistive