Sun, 27 Jul 2008 07:50:10 BST CiteULike: dcastro's power http://www.citeulike.org/user/dcastro/tag/power CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/3041465 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 5. (2000), pp. 868-870.</i><br /><br />In this paper, the power input to the radiating element of an active microstrip patch antenna is measured using a small sensing patch, which is weakly coupled to a radiating edge. Combined with an estimate of patch radiation efficiency, this also yields a measurement of total radiated power. The method has advantages of convenience, insensitivity to room reflections, and a weakly frequency-dependent calibration factor A power and efficiency measurement technique for active patch antennas EA Elkhazmi NJ Mcewan NT Ali doi:10.1109/22.841888 Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 5. (2000), pp. 868-870. 2008-07-25T00:31:39-00:00 2000 Microwave Theory and Techniques, IEEE Transactions on 48 5 868 870 active antenna efficiency measurement patch power http://www.citeulike.org/user/dcastro/article/3039324 <i>Vehicular Technology Magazine, IEEE, Vol. 2, No. 2. (2007), pp. 38-44.</i><br /><br />The investigated design consists of two copper coils, each a self-resonant system. One of the coils, attached to the power source, is the sending unit. Instead of irradiating the environment with electromagnetic waves, it fills the space around it with a non-radiative magnetic field oscillating at MHz frequencies. WiTricity-The Wireless Power Transfer [Mobile Radio] J Gozalvez doi:10.1109/MVT.2007.913285 Vehicular Technology Magazine, IEEE, Vol. 2, No. 2. (2007), pp. 38-44. 2008-07-24T11:59:42-00:00 2007 Vehicular Technology Magazine, IEEE 2 2 38 44 mobile power radio wireless http://www.citeulike.org/user/dcastro/article/3015407 <i>Wireless Communications, IEEE Transactions on, Vol. 5, No. 1. (2006), pp. 16-22.</i><br /><br />In this paper we address the issue of optimizing the performance of data-link and transport protocols running on a system including multiple transmit and receive antennas with a V-BLAST architecture. More specifically, we explore the possibility of adaptively selecting which transmit antennas and which per antenna rates to use as well as the antenna transmit powers in order to maximize the rate of data packets successfully delivered through the system. This is a novel approach with respect to the recent literature which is generally focused on channel capacity optimization. We show that the use of this rate/power adaptation technique, when a data transmission protocol is running over the link, may lead to significant throughput improvements especially at small signal-to-noise ratios. On the use of rate and power adaptation in V-BLAST systems for data protocol performance improvement A Milani V Tralli M Zorzi doi:10.1109/TWC.2006.1576520 Wireless Communications, IEEE Transactions on, Vol. 5, No. 1. (2006), pp. 16-22. 2008-07-17T19:47:06-00:00 2006 Wireless Communications, IEEE Transactions on 5 1 16 22 adaptive capacity data mimo power http://www.citeulike.org/user/dcastro/article/2933329 <i>Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th, Vol. 2 (2002), pp. 899-903 vol.2.</i><br /><br />The power efficiency of the linear modulation signals in terms of the required output back-off of the power amplifier is analyzed and compared, based on a simple approach that deals only with the knowledge of the statistical distribution of the instantaneous power of the input signals. The proposed method may also be useful for predicting the efficiency of the peak-to-average power reduction techniques for single-carrier and OFDM signals for a given level of the adjacent channel power ratio. As widely recognized, the result shows that the efficiency of the OFDM signal is considerably poor without peak power reduction. Thus the improvement of the power efficiency by simple clipping and filtering is also studied. Power efficiency comparison of OFDM and single-carrier signals H Ochiai doi:10.1109/VETECF.2002.1040730 Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th, Vol. 2 (2002), pp. 899-903 vol.2. 2008-06-27T10:40:51-00:00 2002 Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th 2 899 903 vol.2 efficiency ofdm power http://www.citeulike.org/user/dcastro/article/2933326 <i>Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE, Vol. 2 (2000), pp. 731-735 vol.2.</i><br /><br />The effect of digital envelope clipping on the peak power of the bandlimited OFDM signal is studied. The system consists of the concatenation of digital clipping of the OFDM signal with and without oversampling and bandpass filtering, followed by the ideal low-pass filter. It is shown that without oversampling, the clipped OFDM signal may suffer considerable peak power regrowth compared to those with oversampling. To justify this empirical result, the distribution of the instantaneous power in the digitally clipped OFDM signals without oversampling is theoretically analyzed by its lower bound On clipping for peak power reduction of OFDM signals H Ochiai H Imai doi:10.1109/GLOCOM.2000.891236 Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE, Vol. 2 (2000), pp. 731-735 vol.2. 2008-06-27T10:40:44-00:00 2000 Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE 2 731 735 vol.2 clip ofdm papr power http://www.citeulike.org/user/dcastro/article/2933323 <i>Microwave Symposium Digest, 2004 IEEE MTT-S International, Vol. 3 (2004), pp. 1543-1546 Vol.3.</i><br /><br />This paper presents a power amplifier based on envelope tracking (ET) with application to the WLAN 802.11g system. Baseband pre-distortion is implemented to improve the linearity. A high-efficiency wide-bandwidth envelope amplifier and a GaAs MESFET class AB RFPA are designed and implemented for the system. An overall system drain efficiency of 30% is obtained for an OFDM output power of 20 dBm at 2.4GHz. Envelope tracking power amplifier with pre-distortion linearization for WLAN 802.11g Feipeng Wang A Ojo D Kimball P Asbeck L Larson doi:10.1109/MWSYM.2004.1338872 Microwave Symposium Digest, 2004 IEEE MTT-S International, Vol. 3 (2004), pp. 1543-1546 Vol.3. 2008-06-27T10:39:57-00:00 2004 Microwave Symposium Digest, 2004 IEEE MTT-S International 3 1543 1546 Vol.3 amplifier envelope ofdm papr power wifi http://www.citeulike.org/user/dcastro/article/2933315 <i>Information Theory, IEEE Transactions on, Vol. 46, No. 1. (2000), pp. 104-120.</i><br /><br />Controlling the peak-to-mean envelope power ratio (PMEPR) of orthogonal frequency-division multiplexed (OFDM) transmissions is a notoriously difficult problem, though one which is of vital importance for the practical application of OFDM in low-cost applications. The utility of Golay complementary sequences in solving this problem has been recognized for some time. In this paper, a powerful theory linking Golay complementary sets of polyphase sequences and Reed-Muller codes is developed. Our main result shows that any second-order coset of a q-ary generalization of the first order Reed-Muller code can be partitioned into Golay complementary sets whose size depends only on a single parameter that is easily computed from a graph associated with the coset. As a first consequence, recent results of Davis and Jedwab (see Electron. Lett., vol.33, p.267-8, 1997) on Golay pairs, as well as earlier constructions of Golay (1949, 1951, 1961), Budisin (1990) and Sivaswamy (1978) are shown to arise as special cases of a unified theory for Golay complementary sets. As a second consequence, the main result directly yields bounds on the PMEPRs of codes formed from selected cosets of the generalized first order Reed-Muller code. These codes enjoy efficient encoding, good error-correcting capability, and tightly controlled PMEPR, and significantly extend the range of coding options for applications of OFDM using small numbers of carriers Generalized Reed-Muller codes and power control in OFDM modulation KG Paterson doi:10.1109/18.817512 Information Theory, IEEE Transactions on, Vol. 46, No. 1. (2000), pp. 104-120. 2008-06-27T10:35:41-00:00 2000 Information Theory, IEEE Transactions on 46 1 104 120 ofdm papr power http://www.citeulike.org/user/dcastro/article/2920520 <i>Microwave and Wireless Components Letters, IEEE, Vol. 18, No. 1. (2008), pp. 25-27.</i><br /><br />A broadband quadrature power splitter (QPS) is developed using the metamaterial transmission line (MM TL). It consists of a Wilkinson power divider and two phase-adjusting TLs, namely a MM TL and a microstrip (MS). The slope of the phase-response curve of the MM TL is synthesized to be the same as that of the MS along with the 90deg phase increment at two design frequencies. Hence, the broadband quadrature phase difference over the desired frequency range can be obtained. In this letter, the QPS is developed at the center frequency of 2 GHz. Over the frequency range of 1.1-3.5 GHz, an amplitude imbalance of less than 0.9 dB and a phase error of less than plusmn5deg have been experimentally demonstrated. A Broadband Quadrature Power Splitter Using Metamaterial Transmission Line Chao-Hsiung Tseng Chih-Lin Chang doi:10.1109/LMWC.2007.911981 Microwave and Wireless Components Letters, IEEE, Vol. 18, No. 1. (2008), pp. 25-27. 2008-06-24T07:20:16-00:00 2008 Microwave and Wireless Components Letters, IEEE 18 1 25 27 broadband circuit divider metamaterial power http://www.citeulike.org/user/dcastro/article/2897761 <i>Microwave and Wireless Components Letters, IEEE, Vol. 15, No. 11. (2005), pp. 808-810.</i><br /><br />A metamaterial 1:4 series power divider that provides equal power split to all four output ports over a large bandwidth is presented, which can be extended to an arbitrary number of output ports. The divider comprises four nonradiating metamaterial lines in series, incurring a zero insertion phase over a large bandwidth, while simultaneously maintaining a compact length of /spl lambda//sub 0//8. Compared to a series power divider employing conventional one-wavelength long meandered transmission lines to provide in-phase signals at the output ports, the metamaterial divider provides a 165% increase in the input return-loss bandwidth and a 155% and 154% increase in the through-power bandwidth to ports 3 and 4, respectively. In addition, the metamaterial divider is significantly more compact, occupying only 2.6% of the area that the transmission line divider occupies. The metamaterial and transmission line dividers exhibit comparable insertion losses. A broadband series power divider using zero-degree metamaterial phase-shifting lines MA Antoniades GV Eleftheriades doi:10.1109/LMWC.2005.859007 Microwave and Wireless Components Letters, IEEE, Vol. 15, No. 11. (2005), pp. 808-810. 2008-06-16T07:03:20-00:00 2005 Microwave and Wireless Components Letters, IEEE 15 11 808 810 broadband divider metamaterial power http://www.citeulike.org/user/dcastro/article/556628 <i>Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on (2004), pp. 406-414.</i><br /><br />We characterize the fundamental limits of localization using signal strength in indoor environments. Signal strength approaches are attractive because they are widely applicable to wireless sensor networks and do not require additional localization hardware. We show that although a broad spectrum of algorithms can trade accuracy for precision, none has a significant advantage in localization performance. We found that using commodity 802.11 technology over a range of algorithms, approaches and environments, one can expect a median localization error of 10 ft and 97th percentile of 30 ft. We present strong evidence that these limitations are fundamental and that they are unlikely to transcend without a fundamentally more complex environmental models or additional localization infrastructure. The limits of localization using signal strength: a comparative study E Elnahrawy Xiaoyan Li RP Martin doi:10.1109/SAHCN.2004.1381942 Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on (2004), pp. 406-414. 2006-03-19T11:57:34-00:00 2004 Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on 406 414 location power signal http://www.citeulike.org/user/dcastro/article/2845132 <i>Future generation communication and networking (fgcn 2007), Vol. 2 (2007), pp. 536-539.</i><br /><br />In this paper, an frequency offset estimation scheme for orthogonal frequency division multiplexing (OFDM) based packet communication systems is proposed, in which allocated powers of the short training symbols and long training symbols are different while maintaining average power of overall preamble sequence. The preamble structure considered is based on the preamble specified in IEEE802.11a and IEEE802.11p standardization group. From the simulation results, it is shown that the proposed scheme can achieve better mean squared error (MSE) performance for frequency offset estimation error than the conventional scheme. Unequal Preamble Power Allocation Scheme for Frequency Offset Estimation in OFDM Based Packet Communication Systems Jaemin Kwak Kitaek Lim Pusik Park Daekyo Shin Jongchan Choi doi:10.1109/FGCN.2007.228 Future generation communication and networking (fgcn 2007), Vol. 2 (2007), pp. 536-539. 2008-05-29T16:22:20-00:00 2007 Future generation communication and networking (fgcn 2007) 2 536 539 estimation frequency ofdm power preamble http://www.citeulike.org/user/dcastro/article/2839868 <i>Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2007 International Symposium on (2007), pp. 362-365.</i><br /><br />Left-handed transmission lines (LHTLs) are used in this letter to design a novel Wilkinson power divider. In our design, the lumped L-C LHTLs (-lambda/4) is instead of the right-handed transmission lines which is used as branch arms of the conventional Wilkinson power divider. The simulated results show that the novel power divider has a wide bandwidth of return loss and isolation, and its size is 50% smaller than conventional Wilkinson power dividers. The novel Wilkinson power divider has many advantages over conventional power divider in e. g. the size, weight, simplicity, low insertion loss, bandwidth of isolation, and cost. Analysis and Design of a Power Divider Using Metamaterials Li Jiu-Sheng doi:10.1109/MAPE.2007.4393623 Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2007 International Symposium on (2007), pp. 362-365. 2008-05-28T06:59:33-00:00 2007 Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2007 International Symposium on 362 365 analysis design divider metamaterial power 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/2813968 <i>XVIII Symposium Nacional de la Unión Científica Internacional de Radio (2003)</i> Filtro y Divisor de Potencia para un Multiplexor de Entrada en Tecnología Microstrip y Banda Ku Llorente García Salazar Daganzo Galaz Padilla XVIII Symposium Nacional de la Unión Científica Internacional de Radio (2003) 2008-05-19T19:22:34-00:00 2003 XVIII Symposium Nacional de la Unión Científica Internacional de Radio divider microstrip microwave multiplexing power http://www.citeulike.org/user/dcastro/article/2813856 <i>Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE, Vol. 1 (2000), pp. 103-107 vol.1.</i><br /><br />In this paper we present a novel loading algorithm for OFDM-based multiuser communication system to maximize the total system throughput while satisfying the total power and users' rate constraints. The new scheme determines the subcarrier, bit, and power allocation by decoupling an NP-hard combinatorial problem into two steps: (1) resource allocation (how much power and how many subcarriers for each user) based on users' average channel gains and their rate requirements; and (2) subcarrier assignment and bit loading based on users' channel profiles across all subcarriers. Compared to existing iterative methods, the two-step approach offers comparable capacity gain with much lower complexity An efficient multiuser loading algorithm for OFDM-based broadband wireless systems H Yin H Liu doi:10.1109/GLOCOM.2000.891705 Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE, Vol. 1 (2000), pp. 103-107 vol.1. 2008-05-19T18:32:45-00:00 2000 Global Telecommunications Conference, 2000. GLOBECOM '00. IEEE 1 103 107 vol.1 allocation broadband ofdm power wireless http://www.citeulike.org/user/dcastro/article/2813855 <i>Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE, Vol. 1 (2002), pp. 681-685 vol.1.</i><br /><br />In this paper we present a novel and computationally efficient waterfilling algorithm for multiuser OFDM. This algorithm is based on the multiuser waterfilling theorem and determines the subcarrier allocation for a multiple access OFDM system. This approach maximizes the total bitrate under the constraints of user-individual power budgets. Once the subcarrier allocation has been established, the bit and power allocation for each user can be determined with a single-user bitloading algorithm, for which several implementations can be found in the literature. The presented iterative algorithm performs well, also with a high number of subchannels. An efficient waterfilling algorithm for multiple access OFDM G Munz S Pfletschinger J Speidel Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE, Vol. 1 (2002), pp. 681-685 vol.1. 2008-05-19T18:32:42-00:00 2002 Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE 1 681 685 vol.1 allocation capacity ofdma power http://www.citeulike.org/user/dcastro/article/2805135 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 44, No. 12. (1996), pp. 2411-2420.</i><br /><br />Uniplanar coplanar waveguide (CPW), coplanar strip (CPS), and slotline on dielectric substrates have many applications in microwave integrated circuit (MIC) and monolithic microwave/millimeter wave integrated circuit (MMIC) designs. New power dividers using one-section and two-section coupled CPW have been developed. These circuits provide substantially improved performance over a wider bandwidth than conventional microstrip power dividers. Measured results show that the one-section CPW power divider has greater than 20-dB isolation, less than 0.3-dB insertion loss, a 0.2-dB power dividing imbalance, and a 20 phase imbalance over a bandwidth of more than 30% centered at 3 GHz. The two-section CPW power divider has greater than 24-dB isolation, less than 0.5-dB insertion loss, a 0.1 dB power dividing imbalance, and a 1.6° phase imbalance over a bandwidth of more than 66% centered at 3 GHz. Experimental results agree well with calculated ones. In-phase and 180° out-of-phase power dividers constructed by the circuit configuration method are described in this paper. The even-odd mode excited method is used to analyze the power dividers. Also two other power dividers using asymmetrical coplanar strip (ACPS) have been developed with good performance. A 180° out-of-phase power divider is demonstrated with an amplitude imbalance of 0.4 dB and a phase difference of 180°±1° over a wide bandwidth Uniplanar power dividers using coupled CPW and asymmetrical CPS for MICs and MMICs Lu Fan Kai Chang doi:10.1109/22.554570 Microwave Theory and Techniques, IEEE Transactions on, Vol. 44, No. 12. (1996), pp. 2411-2420. 2008-05-16T11:49:28-00:00 1996 Microwave Theory and Techniques, IEEE Transactions on 44 12 2411 2420 divider microwave power tl 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/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/2801356 <i>Radio and Wireless Conference, 1999. RAWCON 99. 1999 IEEE (1999), pp. 231-234.</i><br /><br />An active array with a quasi-Yagi antenna element is presented. The array has a bandwidth of 60% (VSWR <2) and a fan-beam pattern. The gain of the active array is measured to range from 22-25 dB from 8-11.7 GHz. The single layer compact design makes this array antenna ideal as a building block in larger 2-D arrays A broadband uniplanar quasi-Yagi active array for power combining WR Deal J Sor Y Qian T Itoh doi:10.1109/RAWCON.1999.810972 Radio and Wireless Conference, 1999. RAWCON 99. 1999 IEEE (1999), pp. 231-234. 2008-05-15T11:27:42-00:00 1999 Radio and Wireless Conference, 1999. RAWCON 99. 1999 IEEE 231 234 active array broadband combining power http://www.citeulike.org/user/dcastro/article/2801350 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 40, No. 3. (1992), pp. 475-481.</i><br /><br />The authors present analysis, design and experimental results of a 16 element planar oscillator array for quasi-optical power combining. Each element in the array consists of a single FET oscillator with an input port for injection of the locking signal and an output port which is connected to a patch radiator. The array is synchronized using a 16-way power dividing network which distributes the locking signal to the oscillating elements. The array is constructed using a two-sided microstrip configuration, with the oscillators and feed network on one side of a ground plane, and the patch radiators on the opposite side. An effective radiated power (ERP) of 28.2 W CW with an isotropic conversion gain of 9.9 dB was measured at 6 GHz. For an injected power of 10.3 dBm, a locking range of 453 MHz at a center frequency of 6.015 GHz was obtained; a bandwidth of 7.5%. Because of the simple nature of the individual oscillator elements, this approach is well suited to MMIC implementation A 16 element quasi-optical FET oscillator power combining array with external injection locking J Birkeland T Itoh doi:10.1109/22.121722 Microwave Theory and Techniques, IEEE Transactions on, Vol. 40, No. 3. (1992), pp. 475-481. 2008-05-15T11:25:39-00:00 1992 Microwave Theory and Techniques, IEEE Transactions on 40 3 475 481 array combining fet lock optical oscillator power http://www.citeulike.org/user/dcastro/article/2786601 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 82, No. 11. (1982), pp. 1900-1907.</i><br /><br />The noise figure, the gain, and the reflection coefficients of lossy match amplifiers and their dependence on circuit elements are studied. Theoretical results are supported by measured data taken on a two-stage unit. In addition, the performance characteristics of a 100-8800 MHz four-stage lossy match amplifier are discussed. The unit exhibits 23.3 +- 1.1 dB of gain over the nearly 6-1/2 octaves. Its maximum noise figure is 10.9 dB from 100-8800 MHz and 6.6 dB from 2000-8000 MHz. The amplifier's overall circuit dimensions are 10 X 5.7 mm.. On Design and Performance of Lossy Match GaAs MESFET Amplifiers Microwave Theory and Techniques, IEEE Transactions on, Vol. 82, No. 11. (1982), pp. 1900-1907. 2008-05-12T06:26:46-00:00 1982 Microwave Theory and Techniques, IEEE Transactions on 82 11 1900 1907 amplifier equalization power resistive http://www.citeulike.org/user/dcastro/article/2782068 <i>Satellite Communications - ECSC-3, 1993., 3rd European Conference on (1993), pp. 394-398.</i><br /><br />Power amplifier nonlinearity limits the performance of communication systems, both on the ground and in space, through undesirable effects such as crosstalk, intermodulation distortion and reduced signal to noise ratio in the presence of multiple signals. Feedforward linearization is a promising technique for improving the performance of power amplifiers particularly in millimetre wave applications where the power output of currently available devices is limited Feedforward linearization of microwave amplifiers K Konstantinou P Gardner DK Paul Satellite Communications - ECSC-3, 1993., 3rd European Conference on (1993), pp. 394-398. 2008-05-10T00:03:29-00:00 1993 Satellite Communications - ECSC-3, 1993., 3rd European Conference on 394 398 amplifier linearization power http://www.citeulike.org/user/dcastro/article/2782067 <i>Microwave Magazine, IEEE, Vol. 2, No. 4. (2001), pp. 37-49.</i><br /><br />This article discusses techniques for the cancellation of distortion (linearization) in power amplifiers. Different methods of linearization are introduced and compared. The linearization of solid-state power amplifiers (SSPAs), traveling-wave tube amplifiers (TWTAs) and klystron power amplifiers (KPAs) are considered. Although the focus of this article is on power amplifiers, many of the techniques are applicable to other components such as mixers, low-noise amplifiers, and even photonic components, such as lasers and optical modulators Linearization: reducing distortion in power amplifiers A Katz doi:10.1109/6668.969934 Microwave Magazine, IEEE, Vol. 2, No. 4. (2001), pp. 37-49. 2008-05-10T00:03:27-00:00 2001 Microwave Magazine, IEEE 2 4 37 49 amplifier linearization power http://www.citeulike.org/user/dcastro/article/2782041 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 50, No. 3. (2002), pp. 814-826.</i><br /><br />The generation of RF/microwave power is required not only in wireless communications, but also in applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active devices. Power amplifiers are incorporated into transmitters in a similarly wide variety of architectures, including linear, Kalm, envelope tracking, outphasing, and Doherty. Linearity can be improved through techniques such as feedback, feedforward, and predistortion Power amplifiers and transmitters for RF and microwave FH Raab P Asbeck S Cripps PB Kenington ZB Popovic N Pothecary JF Sevic NO Sokal doi:10.1109/22.989965 Microwave Theory and Techniques, IEEE Transactions on, Vol. 50, No. 3. (2002), pp. 814-826. 2008-05-09T23:54:52-00:00 2002 Microwave Theory and Techniques, IEEE Transactions on 50 3 814 826 amplifier microwave power rf transmitter http://www.citeulike.org/user/dcastro/article/2782037 <i>Microwave Magazine, IEEE, Vol. 1, No. 4. (2000), pp. 48-59.</i><br /><br />This article surveys recent progress in the development of high-power microwave and millimeter-wave solid-state sources using spatial power-combining techniques. Several promising topologies are discussed, and four technology demonstrations are presented that have emerged from recent research in academia and industry. We also include a brief discussion of potential applications and systems insertion issues Spatial power combining for high-power transmitters J Harvey ER Brown DB Rutledge RA York doi:10.1109/6668.893246 Microwave Magazine, IEEE, Vol. 1, No. 4. (2000), pp. 48-59. 2008-05-09T23:51:39-00:00 2000 Microwave Magazine, IEEE 1 4 48 59 power transmitter http://www.citeulike.org/user/dcastro/article/2782021 <i>Microwave and Wireless Components Letters, IEEE, Vol. 12, No. 11. (2002), pp. 421-423.</i><br /><br />The authors experimentally investigate and discuss the effects of output harmonic termination on power added efficiency (PAE) and output power of an AlGaN/GaN high electron mobility transistor (HEMT) power amplifier (PA). The AlGaN/GaN HEMT PA with gate periphery of 1 mm was built and tested at L-band. Large-signal measurements and comparisons of the PAE and output power were carried out at different DC bias conditions from 50% of saturated drain current (I/sub dss/) to 1% of Id., for the PA with and without output harmonic termination. For class-AB operation at 25% of I/sub dss/, an increase of about 10% in peak PAE and 1 dBm in output power were observed in saturated output power range. Improvements of up to 9% in PAE and 1.2 dBm in output power were achieved over the measured DC bias conditions provided the output harmonics are properly terminated. Effects of output harmonic termination on PAE and output power of AlGaN/GaN HEMT power amplifier Y Chung CY Hang S Cai Y Chen W Lee CP Wen KL Wang T Itoh doi:10.1109/LMWC.2002.805532 Microwave and Wireless Components Letters, IEEE, Vol. 12, No. 11. (2002), pp. 421-423. 2008-05-09T23:49:18-00:00 2002 Microwave and Wireless Components Letters, IEEE 12 11 421 423 amplifier power http://www.citeulike.org/user/dcastro/article/2776282 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 49, No. 8. (2001), pp. 1477-1482.</i><br /><br />This paper examines some relationships between important design parameters in large combiner systems and key performance objectives such as power, efficiency, noise, and graceful degradation. Results are derived for the combining efficiency of general combiner systems, and used to contrast spatial and corporate combiners and identify optimum combiner topology for a given device technology. The influence of array size on excess phase noise is quantified and shown to decrease with increase numbers of devices. Results are also presented for the degradation in combining efficiency due to statistical variations in amplifier characteristics, appropriate to large combiners, showing that phase errors are the dominant factor in power degradation Some considerations for optimal efficiency and low noise in large power combiners RA York doi:10.1109/22.939929 Microwave Theory and Techniques, IEEE Transactions on, Vol. 49, No. 8. (2001), pp. 1477-1482. 2008-05-09T16:41:57-00:00 2001 Microwave Theory and Techniques, IEEE Transactions on 49 8 1477 1482 microwave noise power http://www.citeulike.org/user/dcastro/article/2776235 <i>Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters], Vol. 8, No. 1. (1998), pp. 13-14.</i><br /><br />Two class AB GaAs field-effect transistor (FET) power amplifiers have been designed and fabricated in the 4.4-4.8 GHz range. In the first case, a dielectric PBG line was incorporated in the design to tune the second harmonic. In the second case, a 50-Ω line is used with no harmonic tuning. The PBG structure allows broad-band harmonic tuning and is inexpensive to fabricate. A 5% improvement in power-added efficiency was achieved at the design frequency of 4.5 GHz, in both simulation and measurement Broad-band power amplifier using dielectric photonic bandgap structure V Radisic Y Qian T Itoh doi:10.1109/75.650973 Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters], Vol. 8, No. 1. (1998), pp. 13-14. 2008-05-09T16:12:55-00:00 1998 Microwave and Guided Wave Letters, IEEE [see also IEEE Microwave and Wireless Components Letters] 8 1 13 14 amplifier broadband pbg power http://www.citeulike.org/user/dcastro/article/2776231 <i>Microwave Magazine, IEEE, Vol. 7, No. 1. (2006), pp. 40-48.</i><br /><br />This article provides a tutorial and review of recent developments in high-efficiency class F RF/ microwave PAs. The principles of class-F RF PAs are explained first. Recent progress in their theory and in design techniques is then presented. Different approaches of class-F PA designs are explained, and some examples of practical designs are illustrated. Finally, an attempt is made to discuss the future developments of class-F RF/microwave PAs. High efficiency class-F RF/microwave power amplifiers S Gao doi:10.1109/MMW.2006.1614233 Microwave Magazine, IEEE, Vol. 7, No. 1. (2006), pp. 40-48. 2008-05-09T16:11:33-00:00 2006 Microwave Magazine, IEEE 7 1 40 48 amplifier power http://www.citeulike.org/user/dcastro/article/2776230 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 51, No. 2. (2003), pp. 653-659.</i><br /><br />A high-efficiency and compact AlGaN/GaN heterojunction field-effect transistor (HFET) power amplifier integrated with a microstrip antenna at 7.25 GHz is presented for RF front-end circuit applications. A microstrip circular sector antenna is employed as both a radiator and frequency-dependent output load. Higher order harmonics from the HFET in nonlinear operation are reactively terminated because of the harmonic termination characteristic of the antenna. Based on the optimum load impedance measured by a load-pull measurement setup, the AlGaN/GaN HFET power amplifier has been designed and fabricated at 7.25 GHz using the active integrated antenna concept. In this design approach, the measured antenna impedance is directly transformed to the optimum load impedance for maximum efficiency. The power amplifier with 1-mm gate periphery shows 42% peak power-added efficiency and 30.3-dBm saturated output power with a linear gain of 8 dB, which is in reasonably good agreement with measured discrete HFET load-pull data. Due to the antenna's characteristics, better than 30-dB harmonic suppression has been achieved at both the second and third harmonic frequencies in both the E- and H-planes. To the authors' best knowledge, this is the first demonstration of a high-frequency AlGaN/GaN HFET power amplifier integrated with an antenna. AlGaN/GaN HFET power amplifier integrated with microstrip antenna for RF front-end applications Younkyu Chung CY Hang S Cai Yongxi Qian CP Wen KL Wang T Itoh doi:10.1109/TMTT.2002.807685 Microwave Theory and Techniques, IEEE Transactions on, Vol. 51, No. 2. (2003), pp. 653-659. 2008-05-09T16:11:09-00:00 2003 Microwave Theory and Techniques, IEEE Transactions on 51 2 653 659 active amplifier antenna integrated power http://www.citeulike.org/user/dcastro/article/2776127 <i>Electronics Letters, Vol. 29, No. 18. (1993), pp. 1633-1635.</i><br /><br />A systematic method for optimising the performance of feedforward linearised microwave power amplifiers has been developed. Simulated and practical feedforward systems optimised with this method achieve significant improvement in third order intermodulation product level and compression point Optimisation method for feedforward linearisation of power amplifiers K Konstantinou P Gardner DK Paul Electronics Letters, Vol. 29, No. 18. (1993), pp. 1633-1635. 2008-05-09T15:21:03-00:00 1993 Electronics Letters 29 18 1633 1635 amplifier power http://www.citeulike.org/user/dcastro/article/2776109 <i>Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 2 (2002), pp. 508-511 vol.2.</i><br /><br />Both theoretical and experimental results of a novel integrated antenna for LINC power amplifiers are presented. The integrated antenna can also serve as a power combiner, ensuring maximum power efficiency. This will be a significant advance on current LINC and CALLIUM systems, where the circuit level power combiner losses degrade overall efficiency. The concept is explained and one example antenna at 1.8 GHz is designed, fabricated and measured. The measured results show that the antenna achieves good impedance matching characteristics under both the common-mode and the differential-mode excitations. Radiation patterns are also presented. Novel integrated antenna for LINC power amplifiers SC Gao P Gardner doi:10.1109/APS.2002.1016133 Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 2 (2002), pp. 508-511 vol.2. 2008-05-09T15:18:04-00:00 2002 Antennas and Propagation Society International Symposium, 2002. IEEE 2 508 511 vol.2 active amplifier antenna integrated power http://www.citeulike.org/user/dcastro/article/2774758 <i>Military Communications Conference, 1998. MILCOM 98. Proceedings., IEEE, Vol. 3 (1998), pp. 699-703 vol.3.</i><br /><br />This paper reports two techniques for optimizing harmonic termination in power amplifiers. In the first technique, the active antenna approach, the antenna element acts as radiator and as part of the output tuning circuit. The second method, based on photonic band-gap (PBG) structure, incorporates a periodic harmonic tuning structure for microstrip lines. In this structure, a periodic 2-D pattern is etched in the microstrip ground plane. A wide stopband suitable for broadband harmonic tuning, has been demonstrated experimentally. These methods yield high efficiency power amplifiers, and reduce unwanted radiation from the antenna at harmonics. Two power amplifier examples are presented Active antenna approach to high efficiency power amplifiers with EMI reduction V Radisic Yongxi Qian T Itoh doi:10.1109/MILCOM.1998.726914 Military Communications Conference, 1998. MILCOM 98. Proceedings., IEEE, Vol. 3 (1998), pp. 699-703 vol.3. 2008-05-09T08:35:16-00:00 1998 Military Communications Conference, 1998. MILCOM 98. Proceedings., IEEE 3 699 703 vol.3 active amplifier antenna efficiency high power http://www.citeulike.org/user/dcastro/article/2774534 <i>Antennas and Propagation, 1995., Ninth International Conference on (Conf. Publ. No. 407) (1995), pp. 175-178 vol.1.</i><br /><br />The design and modelling of an oscillator for use with a hypothetical patch antenna is investigated. The availability of an accurate model for the MRF136 MOSFET prompted the choice of 280 MHz as a convenient operating frequency. To facilitate time domain measurements, a second oscillator at 100 MHz was designed Nonlinear modelling of 1 watt active patch antenna HC Reader K Williams GA Hoile Antennas and Propagation, 1995., Ninth International Conference on (Conf. Publ. No. 407) (1995), pp. 175-178 vol.1. 2008-05-09T06:48:13-00:00 1995 Antennas and Propagation, 1995., Ninth International Conference on (Conf. Publ. No. 407) 175 178 vol.1 active antenna high nonlinear patch power http://www.citeulike.org/user/dcastro/article/2774523 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 12. (2000), pp. 2686-2691.</i><br /><br />This paper presents an optically switched X-band active antenna element for half-duplex transmit/receive (T/R) applications. The antenna element is designed to be a unit cell of a quasioptical array with fast switching between T and R and with built-in phase-shifterless beamforming. The measured performance of the active element is 14 dB gain contributed by the power amplifier (PA) in transmission and 16 dB gain contributed by the low-noise amplifier in reception, with 30 dB isolation between T and R. The switching is accomplished with only 1 μW of optical power for 1.7 μs switching time (1.7 pJ of optical energy) and a rise time of 2 ns at 10 GHz with 7 mW of optical power (14 pJ of optical energy). The design, implementation, and measured performance of the optically controlled transmit/receive circuit are presented A transmit/receive active antenna with fast low-power optical switching J Vian Z Popovic doi:10.1109/22.899031 Microwave Theory and Techniques, IEEE Transactions on, Vol. 48, No. 12. (2000), pp. 2686-2691. 2008-05-09T06:44:38-00:00 2000 Microwave Theory and Techniques, IEEE Transactions on 48 12 2686 2691 active antenna fast low power receiver transceiver transmiter http://www.citeulike.org/user/dcastro/article/2762249 <i>Microwave Symposium Digest, 1991., IEEE MTT-S International (1991), pp. 1257-1260 vol.3.</i><br /><br />A Gunn device in a varactor-tuned slotline coplanar waveguide (CPW) resonator has been integrated with a planar, endfire notch antenna. The varactor provides more than 14% tuning bandwidth centered at 9.6 GHz, with a power output of 14.5±-0.8 dBm. Wideband tunable quasi-optical power combiners have also been developed using the active elements. The signal spectrum remains clean and very stable with nearly constant power output throughput the electronic tuning range. These results offer a simple, lightweight, low-cost, reproducible, and truly planar active wideband tunable source for many microwave applications Wideband integrated varactor-tunable active notch antennas and power combiners JA Navarro YH Shu K Chang doi:10.1109/MWSYM.1991.147250 Microwave Symposium Digest, 1991., IEEE MTT-S International (1991), pp. 1257-1260 vol.3. 2008-05-06T18:35:43-00:00 1991 Microwave Symposium Digest, 1991., IEEE MTT-S International 1257 1260 vol.3 active antenna combining integrated power wideband http://www.citeulike.org/user/dcastro/article/2762239 <i>Circuits, Devices and Systems, IEE Proceedings G, Vol. 136, No. 6. (1989), pp. 358-360.</i><br /><br />A novel method of determining the source and drain series parasitic resistances of the MESFET is presented. This method is particularly suited to power devices since it eliminates the necessity to operate the Schottky gate with high forward bias. In addition, the values of parasitic resistances extracted from low-frequency measurements are confirmed at microwave frequencies.<<ETX>> Method for determination of parasitic resistances in microwave power MESFETs KW Eccleston Circuits, Devices and Systems, IEE Proceedings G, Vol. 136, No. 6. (1989), pp. 358-360. 2008-05-06T18:33:16-00:00 1989 Circuits, Devices and Systems, IEE Proceedings G 136 6 358 360 amplifier fet microwave power http://www.citeulike.org/user/dcastro/article/2762237 <i>Singapore ICCS '94. Conference Proceedings., Vol. 1 (1994), pp. 246-250 vol.1.</i><br /><br />In solid-state power amplification, power combining is an important issue since the output powers from individual transistors are too small for many transmission applications. An important aspect of power combining is the combining efficiency being the ratio of the power delivered to the load to that available from the sources connected to the input. In a practical power combiner, waves incident on the input ports are scattered to all ports including the output port. The paper discusses the effects of port mismatch and finite combiner isolation on combining efficiency. For a lossless power combiner, it is shown that the efficiency may be optimised by optimising the matching at the combiner output Consequences of port mismatch and finite isolation on power combining KW Eccleston doi:10.1109/ICCS.1994.474069 Singapore ICCS '94. Conference Proceedings., Vol. 1 (1994), pp. 246-250 vol.1. 2008-05-06T18:33:10-00:00 1994 Singapore ICCS '94. Conference Proceedings. 1 246 250 vol.1 combining power http://www.citeulike.org/user/dcastro/article/2762236 <i>Microwave Conference, 1999 Asia Pacific, Vol. 3 (1999), pp. 638-641 vol.3.</i><br /><br />The dual-fed distributed amplifier is a variation of the conventional single-fed distributed amplifier. Namely, the input signal is fed to both ends of the input line and the power appearing at the ends of the output line is combined. This approach has the advantages of utilising power in both the forward and backward travelling waves on the output line, and the drain output power can be equalised among the FETs. In this paper, the operational behaviour of the dual-fed distributed power amplifier is investigated and the optimum operating conditions are identified. It has been shown that uniform power distribution can be achieved when the spacing between each FET is of the order of the guide wavelength and is dependent on the phase difference of the two input signals Analysis of the dual-fed distributed power amplifier KW Eccleston LT Ong PS Kooi BL Ooi doi:10.1109/APMC.1999.833672 Microwave Conference, 1999 Asia Pacific, Vol. 3 (1999), pp. 638-641 vol.3. 2008-05-06T18:33:09-00:00 1999 Microwave Conference, 1999 Asia Pacific 3 638 641 vol.3 amplifier distributed power http://www.citeulike.org/user/dcastro/article/2762235 <i>Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on (2002), pp. 1142-1145.</i><br /><br />RF sub-systems in multimode/multiband wireless communication systems need to operate on different bands that are typically narrow but sparsely separated. We show that a single-ended dual-fed distributed amplifier can operate efficiently over several sparsely separated bands. This approach therefore alleviates the need for separate amplifiers for each band. Multiband power amplifier for multiband wireless applications KW Eccleston Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on (2002), pp. 1142-1145. 2008-05-06T18:33:07-00:00 2002 Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on 1142 1145 amplifier multiband power http://www.citeulike.org/user/dcastro/article/2762234 <i>Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on (2002), pp. 919-922.</i><br /><br />The distributed amplifier approach allows the output powers of several FETs to be combined without the need for multi-way power combiners. In this paper we demonstrate that a balanced amplifier employing two single-ended dual-fed distributed amplifiers can operate effectively under class-B operation. Class-B operation and dual-feeding allow distributed amplification with significantly improved efficiencies compared to conventional distributed power amplifiers. The FETs are spaced 180 degrees to allow all FETs operate into identical optimum loadlines. The configuration uses all FET output power and has good port match. Class-B balanced single-ended dual-fed distributed power amplifier O Kyaw KW Eccleston Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on (2002), pp. 919-922. 2008-05-06T18:33:06-00:00 2002 Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on 919 922 amplifier distributed power http://www.citeulike.org/user/dcastro/article/2762233 <i>Microwave Conference, 2000 Asia-Pacific (2000), pp. 205-208.</i><br /><br />The dual-fed distributed amplifier is a variation of the conventional single-fed distributed amplifier whereby the input signal is fed to both ends of the input line using a hybrid, and signals appearing at both ends of the output line are combined using another hybrid. Such a configuration allows utilisation of output power in the backward as well as forward waves. Much of the previous work in the literature only considered small-signal analysis and small electrical spacing between FETs, and did not lend insight into the operational behaviour. This paper therefore considers the development of a design method for the dual-fed distributed power amplifier with large electrical spacing. The simulations demonstrate optimum loadlines are achieved for all FETs and that all FET output power is utilised Design considerations for the dual-fed distributed power amplifier KW Eccleston doi:10.1109/APMC.2000.925763 Microwave Conference, 2000 Asia-Pacific (2000), pp. 205-208. 2008-05-06T18:33:03-00:00 2000 Microwave Conference, 2000 Asia-Pacific 205 208 amplifier design distributed power http://www.citeulike.org/user/dcastro/article/2762228 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 53, No. 3. (2005), pp. 825-831.</i><br /><br />The dual-fed distributed amplifier (DFDA) allows efficient combining of field-effect transistors (FETs) at the device level without using n-way power combiners. However, the FETs must be spaced 180/spl deg/, resulting in physically large circuits. In this paper, meandered artificial transmission lines (TLs) comprised of microstrip lines periodically loaded with short open-circuit stubs can be used in place of TLs to reduce the size. The approach incorporates FET input and output capacitances with the artificial TLs, thereby eliminating their detrimental effects on bandwidth and performance. Both simulation and experimental results of a class-A three-FET single-ended DFDA designed to operate at 1.8 GHz demonstrate the feasibility of this approach and the validity of the design method. The size reduction is approximately one-third compared to realization using microstrip lines only, and the maximum efficiency is greater than 35% over a bandwidth of 15%. Compact dual-fed distributed power amplifier KW Eccleston doi:10.1109/TMTT.2004.842508 Microwave Theory and Techniques, IEEE Transactions on, Vol. 53, No. 3. (2005), pp. 825-831. 2008-05-06T18:31:05-00:00 2005 Microwave Theory and Techniques, IEEE Transactions on 53 3 825 831 amplifier distributed power http://www.citeulike.org/user/dcastro/article/2762227 <i>Microwave Conference, 2001. APMC 2001. 2001 Asia-Pacific, Vol. 3 (2001), pp. 1187-1190 vol.3.</i><br /><br />In this paper we demonstrate a design method for the balanced amplifier employing two single-ended dual-fed distributed power amplifiers. The method ensures that all FET output power is utilised, all FETs have equal output power at the centre frequency and operate into identical, optimum loadlines. The amplifier has improved efficiency compared to the conventional distributed amplifier and has improved input and output match compared to the dual-fed distributed amplifier Design and performance of a balanced single-ended dual-fed distributed power amplifier KW Eccleston doi:10.1109/APMC.2001.985345 Microwave Conference, 2001. APMC 2001. 2001 Asia-Pacific, Vol. 3 (2001), pp. 1187-1190 vol.3. 2008-05-06T18:31:02-00:00 2001 Microwave Conference, 2001. APMC 2001. 2001 Asia-Pacific 3 1187 1190 vol.3 amplifier power http://www.citeulike.org/user/dcastro/article/2762158 <i>Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 1 (2002), pp. 433-436.</i><br /><br />In this paper, effects of output harmonic terminations on PAE and output power of AlGaN/GaN HEMT power amplifier are investigated. Using a traditional method of harmonic termination, we observe a substantial increase in PAE and output power. Further, we demonstrate the high efficiency AlGaN/GaN HEMT power amplifier with harmonic termination characteristics by using the active integrated antenna approach. For the microstrip-based AlGaN/GaN HEMT power amplifier, large signal measurements and comparisons of PAE and output power were done in class-AB operation with and without output harmonic terminations. For the antenna integrated power amplifier using an AlGaN/GaN HEMT with 1 mm gate periphery, output power of 30 dBm and peak PAE of 55 % with a power gain of 14 dB were achieved at a drain voltage of 18 V and a gate voltage of -2.8 V Output harmonic termination techniques for AlGaN/GaN HEMT power amplifiers using active integrated antenna approach Younkyu Chung CY Hang Shujun Cai Yongxi Qian CP Wen KL Wang T Toh doi:10.1109/MWSYM.2002.1011648 Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 1 (2002), pp. 433-436. 2008-05-06T17:44:54-00:00 2002 Microwave Symposium Digest, 2002 IEEE MTT-S International 1 433 436 active amplifier antenna integrated power http://www.citeulike.org/user/dcastro/article/2762157 <i>Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 2 (2002), pp. 913-916.</i><br /><br />This paper presents a new power combining scheme, which has either one or four amplifiers on depending upon the levels of input signal. This approach realized by utilizing a unique combiner that is lossless and has constant gain under both scenarios. As a result, for the system where variable output power is required, this combining scheme can be used in an amplifier design with optimum efficiency. Measurement data show 15% power efficiency for the four-amplifier scenario and 28% for the single amplifier scenario at 13dBm input power. We also investigate the possibility of using this combiner in an envelope tracking amplifier A new amplifier power combining scheme with optimum efficiency under variable outputs CY Hang Y Wang T Itoh doi:10.1109/MWSYM.2002.1011778 Microwave Symposium Digest, 2002 IEEE MTT-S International, Vol. 2 (2002), pp. 913-916. 2008-05-06T17:44:51-00:00 2002 Microwave Symposium Digest, 2002 IEEE MTT-S International 2 913 916 amplifier efficiency power http://www.citeulike.org/user/dcastro/article/2762156 <i></i><br /><br />In this paper, a high efficiency class-AB pushpull power amplifier is designed utilizing a novel photonic band-gap (PBG) ground plane. This design allows simultaneous tuning of both second and the third harmonics, thus, results in a high efficient power amplifier design. The measured PAE is 63.8% at an output power of 28.2dBm. In addition, the measured IP3 is 45 dBm, about 17 dB above the P 1dB point. . High Efficiency S-band Class AB Push-Pull Power Amplifier with Wide Band Harmonic Suppression Cynthia Hang Yongxi Qian Tatsuo Itoh 2008-05-06T17:44:50-00:00 amplifier power http://www.citeulike.org/user/dcastro/article/2762155 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 3 (1998), pp. 1895-1898 vol.3.</i><br /><br />A high efficiency class-AB GaAs FET power amplifier integrated with a slot antenna has been designed and fabricated. Broadband second harmonic tuning was achieved using a microstrip line with a periodically etched ground plane. Power-added efficiency greater than 50% was achieved in the 3.7-4.0 GHz bandwidth Broadband power amplifier integrated with slot antenna and novel harmonic tuning structure V Radisic Yongxi Qian T Itoh doi:10.1109/MWSYM.1998.700863 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 3 (1998), pp. 1895-1898 vol.3. 2008-05-06T17:44:46-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 3 1895 1898 vol.3 active amplifier antenna integrated power http://www.citeulike.org/user/dcastro/article/2762148 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 589-592 vol.2.</i><br /><br />This paper presents a technique for raising power efficiency in portable wireless transmitters by integrating a variable voltage output DC-DC converter together with a MESFET RF power amplifier. Significant increases in power efficiency are obtainable over a large range of output power levels. The system includes an envelope detector, a closed feedback loop, and a pulse width modulator operating at 10 MHz. A 300 mW transmitter is shown for which battery life can be extended by over 1.4 times Microwave power amplifier efficiency improvement with a 10 MHz HBT DC-DC converter G Hanington PF Chen V Radisic T Itoh PM Asbeck doi:10.1109/MWSYM.1998.705062 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 589-592 vol.2. 2008-05-06T17:42:50-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 2 589 592 vol.2 amplifier power