Sun, 27 Jul 2008 07:48:58 BST CiteULike: dcastro's gain http://www.citeulike.org/user/dcastro/tag/gain CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/3041456 <i>IEEE Std 145-1993 (1993), i.</i> IEEE standard definitions of terms for antennas. IEEE Std 145-1993 (1993), i. 2008-07-25T00:27:08-00:00 1993 IEEE Std 145-1993 i antenna definition gain http://www.citeulike.org/user/dcastro/article/3041451 <i>Antennas and Propagation Society Newsletter, IEEE, Vol. 20, No. 6. (1978), pp. 13-14.</i> A note on power gain and directive gain J Hollis Antennas and Propagation Society Newsletter, IEEE, Vol. 20, No. 6. (1978), pp. 13-14. 2008-07-25T00:25:47-00:00 1978 Antennas and Propagation Society Newsletter, IEEE 20 6 13 14 definition gain http://www.citeulike.org/user/dcastro/article/3041448 <i>Antennas and Propagation Magazine, IEEE, Vol. 40, No. 4. (1998), pp. 7-11.</i><br /><br />Gain is the most important performance parameter of an antenna. However, in many practical situations it is not possible to measure or calculate the gain of an antenna. Also, the interest in wireless applications has increased the need of system engineers to accurately estimate antenna gain. Many simple formulas are available for estimating gain. But, each formula has a range of applicability, and inappropriate use of these formulas will result in inaccurate gain values. This paper explains the process of gain evaluation, and gives several simple gain-estimation formulas, together with recommendations for their use Estimating directivity and gain of antennas WL Stutzman doi:10.1109/74.730532 Antennas and Propagation Magazine, IEEE, Vol. 40, No. 4. (1998), pp. 7-11. 2008-07-25T00:25:16-00:00 1998 Antennas and Propagation Magazine, IEEE 40 4 7 11 antenna directivity gain http://www.citeulike.org/user/dcastro/article/3041441 <i>Antennas and Propagation, IEEE Transactions on, Vol. 48, No. 12. (2000), pp. 1818-1829.</i><br /><br />A basic system-level model for the gain and G/T of active multielement receive antennas is presented that covers arbitrary beamforming networks and direct radiating arrays, as well as array-fed systems with one or more focusing elements (reflectors or lenses). Since the model is based on measurable parameters and uses definitions, which are consistent with conventional communication system analysis terms, it can be applied directly to the analysis and design of systems using such antennas and can be used to support the specification, design, and test of such antennas as well, measurement possibilities for the basic parameters are discussed and the characteristic parameters of generic active beamforming networks are derived and compared. Finally, the impact of the different parameters on the overall antenna gain and G/T is illustrated by one application example that covers a reconfigurable multifeed reflector antenna with selectable beamwidth. The presented theory has been verified successfully in the frame of a classified EHF antenna development whose details cannot be reported here Gain and G/T of multielement receive antennas with active beamforming networks UR Kraft doi:10.1109/8.901270 Antennas and Propagation, IEEE Transactions on, Vol. 48, No. 12. (2000), pp. 1818-1829. 2008-07-25T00:17:11-00:00 2000 Antennas and Propagation, IEEE Transactions on 48 12 1818 1829 active antenna beamformer gain noise temperature http://www.citeulike.org/user/dcastro/article/3041440 <i>Antennas and Propagation, IEEE Transactions on, Vol. 47, No. 3. (1999), pp. 443-452.</i><br /><br />In this work, noise analysis of parallel feed structures is presented. Signal and noise behavior of the feed structures are signified by the newly introduced concepts of “coherent” and “incoherent” impedance match of power-combining structures. It is also shown that a feed structure can be redesigned for low-noise operation without affecting the radiation characteristics. Optimum design of parallel feed structures for low-noise operation is explained. Also an optimum use of active elements in such structures is investigated to have a low overall noise temperature of the antenna array with minimum number of active elements. In the analysis, a new method is introduced where a “noise-equivalent line length” (NELL) is defined. This definition, which unifies the contribution of noise from different array elements, is used in the design of a parallel feed structure and as an active circuit replacement criteria in passive arrays Optimum design of feed structures for high G/T passive and active antenna arrays S Demir C Toker doi:10.1109/8.768778 Antennas and Propagation, IEEE Transactions on, Vol. 47, No. 3. (1999), pp. 443-452. 2008-07-25T00:17:09-00:00 1999 Antennas and Propagation, IEEE Transactions on 47 3 443 452 active antenna array gain noise passive temperature http://www.citeulike.org/user/dcastro/article/3041433 <i>Antennas and Propagation Society International Symposium, 1997. IEEE., 1997 Digest, Vol. 4 (1997), pp. 2468-2471 vol.4.</i><br /><br />Multi-feed reflector antennas (MRAs) with suitable beamforming networks (BFNs) are the preferred solution for satellites in the geostationary orbit (GEO), since the GEO requires narrow beams with a limited scan range. For satellites in a low Earth orbit (LEO) direct radiating phased arrays can be attractive, since wider beams with larger scan angles are required in this case. The authors provide a general description for the most system-relevant parameters such as gain, noise temperature and G/T of an active receive antenna, which covers both MRAs and phased arrays and which is based on measurable antenna parameters. Apart from the use for system analysis and design, this description can be applied also to obtain useful specifications for such antennas and to provide some insight into their basic behavior in comparison to conventional passive types Gain- and G/T-considerations on spaceborne active receive antennas UR Kraft DUE Blaschke doi:10.1109/APS.1997.625501 Antennas and Propagation Society International Symposium, 1997. IEEE., 1997 Digest, Vol. 4 (1997), pp. 2468-2471 vol.4. 2008-07-25T00:12:38-00:00 1997 Antennas and Propagation Society International Symposium, 1997. IEEE., 1997 Digest 4 2468 2471 vol.4 active antenna gain noise temperature http://www.citeulike.org/user/dcastro/article/3041434 <i>Antennas and Propagation, IEEE Transactions on, Vol. 41, No. 2. (1993), pp. 241-244.</i><br /><br />A figure of merit, <e1>G</e1>/<e1>T</e1>, for a multichannel active array antenna was derived, and the effects of the beamforming network on the overall noise figure of the system were studied. Also examined are the dependence of the noise figure on various losses, and the difference between a resistive and nonresistive taper in the combining network. When the amplifier gain is sufficiently large, the losses following the LNA can usually be ignored. For a photonic array with lossy time shift elements, however, the downstream losses become significant. Also, if resistive tapering is employed, not only the array gain but also the noise figure will be degraded by the collective effect of the feed network <e1>G</e1>/<e1>T</e1> and noise figure of active array antennas JJ Lee doi:10.1109/8.214619 Antennas and Propagation, IEEE Transactions on, Vol. 41, No. 2. (1993), pp. 241-244. 2008-07-25T00:12:39-00:00 1993 Antennas and Propagation, IEEE Transactions on 41 2 241 244 active antenna array gain noise temperature http://www.citeulike.org/user/dcastro/article/3025721 <i>Microwave Conference, 2007. APMC 2007. Asia-Pacific (2007), pp. 1-4.</i><br /><br />This paper presents the design and study of a stacked Identical dual square microstrip antenna to enhance its gain and bandwidth that is optimal for WLAN applications. The proposed antenna with an air-gap of 9 mm, resonates at 2.45 GHz with a gain of 8.05 dBi. The bandwidth achieved is 12.72% within 2:1VSWR. Gain and Bandwidth Enhancement Technique in Square Microstrip Antenna for WLAN Applications K Shambavi doi:10.1109/APMC.2007.4554884 Microwave Conference, 2007. APMC 2007. Asia-Pacific (2007), pp. 1-4. 2008-07-21T21:47:53-00:00 2007 Microwave Conference, 2007. APMC 2007. Asia-Pacific 1 4 antenna bandwidth gain microstrip patch wlan http://www.citeulike.org/user/dcastro/article/2920479 <i>Antennas and Propagation, IEEE Transactions on, Vol. 54, No. 8. (2006), pp. 2292-2300.</i><br /><br />A novel high-gain active composite right/left-handed (CRLH) metamaterial leaky-wave antenna (LWA) is presented. This antenna, which is designed to operate at broadside, is constituted by passive CRLH leaky-wave sections interconnected by amplifiers, which regenerate the power progressively leaked out of the structure in the radiation process in order to increase the effective aperture of the antenna and thereby its gain. The gain is further enhanced by a matching regeneration effect induced by the quasi-unilateral nature of the amplifiers. Both the cases of quasi-uniform and binomial field distributions, corresponding to maximum directivity and minimum side-lobe level, respectively, have been described. An active LWA prototype is demonstrated in transmission mode with a gain enhancement of 8.9 dB compared to its passive counterpart. The proposed antenna can attain an arbitrarily high gain by simple increase of the length of the structure, without penalty in terms of return loss and without requiring a complicated feeding network like conventional array antennas. High-gain active composite right/left-handed leaky-wave antenna FP Casares-Miranda C Camacho-Penalosa C Caloz doi:10.1109/TAP.2006.879210 Antennas and Propagation, IEEE Transactions on, Vol. 54, No. 8. (2006), pp. 2292-2300. 2008-06-24T07:03:54-00:00 2006 Antennas and Propagation, IEEE Transactions on 54 8 2292 2300 active antenna crlh gain metamaterial http://www.citeulike.org/user/dcastro/article/2802223 <i>Universal Personal Communications Record, 1997. Conference Record., 1997 IEEE 6th International Conference on, Vol. 2 (1997), pp. 371-375 vol.2.</i><br /><br />The nonlinear renewal process approach (RPA) is applied to analyze the noncoherent sum-difference loop (SDL) with gain and phase imbalance for spread spectrum systems. In the analysis, the code acquisition boundary is equal to the branch offset, 0<δ&les;1. The results indicate that under phase imbalance, when δ&ges;0.5 and with gain balance, the values of the DC bias of the SDL are small and will not change with the loop signal-to-noise ratio (SNR); when δ<0.5 and with a low loop SNR, the DC bias becomes larger which will result in the SDL loss of lock. A larger branch offset may result in a higher mean-time-to-lose-lock (MTLL) for the SDL with gain and phase imbalance; however, the RMS tracking error has not obviously changed with the increasing branch offset. Furthermore, it is shown that in case where the early and late branch of the SDL can not be implemented with equal gain, one can get better performance results by putting the arm with smaller gain in the late branch of the SDL Effects of gain and phase imbalance on sum-difference code tracking loop's performance in spread spectrum systems Jeich Mar Mou-Chih Chung doi:10.1109/ICUPC.1997.627189 Universal Personal Communications Record, 1997. Conference Record., 1997 IEEE 6th International Conference on, Vol. 2 (1997), pp. 371-375 vol.2. 2008-05-15T17:46:37-00:00 1997 Universal Personal Communications Record, 1997. Conference Record., 1997 IEEE 6th International Conference on 2 371 375 vol.2 code gain loop phase spread-spectrum tracking 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/2786603 <i>Circuits and Systems, IEEE Transactions on, Vol. 24, No. 4. (1977), pp. 170-175.</i><br /><br />A new idea for treating the broad-band matching of an arbitrary load to a resistive generator leads to a simple technique for the design of a lossless 2-port equalizer. The method is a numerical one, and only utilizes real frequency (e.g., experimental) load impedance data. No model or analytic impedance function for the load is necessary. Nor is the equalizer topology or analytic form of the system transfer function assumed. The arithmetic is well conditioned and the intricacies of gainbandwidth theory are bypassed. An example comparing the method with analytic gain-bandwidth theory is given. Two examples proceeding directly from experimental data are presented. One is the broad banding of a microwave avalanche diode reflection amplifier. The other is the gainbandwidth equalization of a microwave FET amplifier for gain taper and impedance mismatch. A new approach to gain-bandwidth problems H Carlin Circuits and Systems, IEEE Transactions on, Vol. 24, No. 4. (1977), pp. 170-175. 2008-05-12T06:27:40-00:00 1977 Circuits and Systems, IEEE Transactions on 24 4 170 175 bandwidth gain matching microwave http://www.citeulike.org/user/dcastro/article/2776111 <i>Electronics Letters, Vol. 29, No. 16. (1993), pp. 1408-1409.</i><br /><br />The limited gain available from GaAs FETs and HEMTs at millimetric frequencies can be overcome by using the devices in a negative resistance amplifier configuration. The advantage of the solid-state negative resistance amplifier over the transmission amplifier is that the gain available is not limited by the active device used. It has been shown that, over a narrow bandwidth, significantly higher gain can be obtained from a negative resistance amplifier, when compared to a transmission amplifier using the same device, while maintaining the same overall noise performance. This has been demonstrated experimentally using a 0.25 μm HEMT device High gain millimetric negative resistance low noise amplifiers MT Hickson P Gardner DK Paul Electronics Letters, Vol. 29, No. 16. (1993), pp. 1408-1409. 2008-05-09T15:18:07-00:00 1993 Electronics Letters 29 16 1408 1409 amplifier gain high low noise http://www.citeulike.org/user/dcastro/article/2774520 <i>Radio and Wireless Conference, 1998. RAWCON 98. 1998 IEEE (1998), pp. 221-224.</i><br /><br />The microstrip patch is one of the most preferred antenna structures for low-cost and compact design of wireless communication systems and RF sensors. To overcome several intrinsic limitations of the patch antenna such as narrow bandwidth, low gain, and degradation of radiation efficiency at higher frequencies, we propose a novel technique for gain and bandwidth enhancement based on the photonic band-gap (PBG) concept. The Ku-band prototype demonstrates over 3 times bandwidth improvement, and 1.6 dB higher gain or 45% increase in effective radiated power (ERP), compared with a regular patch with identical dimensions. System design issues such as co-site interference can also be alleviated by the improved beam patterns of the new PBG antenna A novel approach for gain and bandwidth enhancement of patch antennas Yongxi Qian D Sievenpiper V Radisic E Yablonovitch T Itoh doi:10.1109/RAWCON.1998.709176 Radio and Wireless Conference, 1998. RAWCON 98. 1998 IEEE (1998), pp. 221-224. 2008-05-09T06:44:33-00:00 1998 Radio and Wireless Conference, 1998. RAWCON 98. 1998 IEEE 221 224 active antenna bandwidth gain patch http://www.citeulike.org/user/dcastro/article/2674665 <i>Information Theory, 1994. Proceedings., 1994 IEEE International Symposium on (1994), 344.</i><br /><br />Due to a malfunctioning high-gain antenna, the Galileo spacecraft is transmitting all its data through a low-gain antenna, and the data rate will seldom exceed 100 bits per second during its two-year tour of Jupiter's satellites. To offset some of the performance loss, the spacecraft's computer will be extensively reprogrammed to include new data compression and coding algorithms. The baseline coding system for the low gain antenna mission uses a Reed-Solomon (RS) outercode of block length 255 concatenated with a (14, 1/4) convolutional inner code, and interleaves the RS symbols to depth eight. The convolutionally encoded symbols are decoded by a maximum likelihood (Viterbi) decoder, and each RS codeword is decoded algebraically. Two types of decoding enhancements were proposed as feasible due to the low data rate. The first type of redecoding is confined to the RS decoder and utilizes information from neighboring codewords within the same interleaved block to erase unreliable symbols in undecoded words. The second type involves redecoding by the Viterbi decoder, using information fed back from codewords successfully decoded by the RS decoder Enhanced decoding for the Galileo low-gain antenna mission S Dolinar M Belongie doi:10.1109/ISIT.1994.394674 Information Theory, 1994. Proceedings., 1994 IEEE International Symposium on (1994), 344. 2008-04-15T18:05:18-00:00 1994 Information Theory, 1994. Proceedings., 1994 IEEE International Symposium on 344 antenna gain galileo low small http://www.citeulike.org/user/dcastro/article/2674620 <i>Antenna Technology: Small and Smart Antennas Metamaterials and Applications, 2007. IWAT '07. International Workshop on (2007), pp. 384-387.</i><br /><br />The fundamental limits of the gain, efficiency and Q-value of an antenna put severe restrictions on small antennas. In this paper it is discussed how one can avoid low efficiency and high Q-values in small antennas by examining the far-field pattern of the antenna. The analysis is based on the expansion of the electromagnetic fields in terms of vector spherical harmonics. Efficiency, gain and Q of antennas A Karlsson doi:10.1109/IWAT.2007.370155 Antenna Technology: Small and Smart Antennas Metamaterials and Applications, 2007. IWAT '07. International Workshop on (2007), pp. 384-387. 2008-04-15T18:01:31-00:00 2007 Antenna Technology: Small and Smart Antennas Metamaterials and Applications, 2007. IWAT '07. International Workshop on 384 387 antenna efficiency gain http://www.citeulike.org/user/dcastro/article/2072415 <i>Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 24, No. 6. (1976), pp. 837-841.</i><br /><br />It is shown that there is an optimum nonzero value of mutual coupling and passive reflection coefficient that is a function of only the embedded element pattern and element spacing. Optimum is defined as yielding maximum array gain. For closely spaced arrays, the optimum mutual coupling and passive reflection coefficient are quite large, but tend to cancel in the active mode to produce a low active reflection coefficient. A smaller value of mutual coupling would give lower gain than the optimum case. This again demonstrates that mutual coupling is a natural and desirable effect in array behavior. It is well known that it is possible to achieve array superdirectivity, in the sense that the directivity of an array of "<tex>N</tex>" elements is greater than "<tex>N</tex>" times the embedded element directivity; however, in this case the mutual coupling and passive reflection produce an active reflection coefficient that results in an array gain lower than "<tex>N</tex>" times the embedded element gain. In fact, higher superdirectivity always implies lower gain, relative to embedded element gain. Mutual coupling, gain and directivity of an array of two identical antennas A Ludwig Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988], Vol. 24, No. 6. (1976), pp. 837-841. 2007-12-07T10:19:19-00:00 1976 Antennas and Propagation, IEEE Transactions on [legacy, pre - 1988] 24 6 837 841 antenna gain performance http://www.citeulike.org/user/dcastro/article/2072403 <i>Vehicular Technology, IEEE Transactions on, Vol. 46, No. 3. (1997), pp. 537-543.</i><br /><br />This paper presents antenna-gain measurements of handheld terminals by the random-field measurement (RFM) method. We have measured the relative antenna gain for different-sized terminal boxes in indoor and outdoor environments to show a gain decrease caused by the box size. The measured results are explained by calculating the average gain of the horizontal radiation pattern. To find the effect by a different human carrier, we also measured the antenna gain for several parameters, such as weight, height, head parameters, and the antenna protruding length from the head. We present a correlation factor of the antenna-gain deviation due to different human carriers Antenna-gain measurement of handheld terminals at 900 MHz H Arai N Igi H Hanaoka Vehicular Technology, IEEE Transactions on, Vol. 46, No. 3. (1997), pp. 537-543. 2007-12-07T10:13:04-00:00 1997 Vehicular Technology, IEEE Transactions on 46 3 537 543 antenna gain measurement mobile