Topic
Antenna (radio)
About: Antenna (radio) is a(n) research topic. Over the lifetime, 208070 publication(s) have been published within this topic receiving 1896766 citation(s). The topic is also known as: aerial & transmitter.
...read more
Papers
More
Open access•Book•
01 Jan 1982-
Abstract: The most-up-to-date resource available on antenna theory and design Expanded coverage of design procedures and equations makes meeting ABET design requirements easy and prepares readers for authentic situations in industry New coverage of microstrip antennas exposes readers to information vital to a wide variety of practical applicationsComputer programs at end of each chapter and the accompanying disk assist in problem solving, design projects and data plotting-- Includes updated material on moment methods, radar cross section, mutual impedances, aperture and horn antennas, and antenna measurements-- Outstanding 3-dimensional illustrations help readers visualize the entire antenna radiation pattern
...read more
Topics: Microstrip antenna (58%), Antenna (radio) (57%)
14,060 Citations
Open access•Book•
01 Jan 1981-
Abstract: Antenna Fundamentals and Definitions. Some Simple Radiating Systems and Antenna Practice. Arrays. Line Sources. Resonant Antennas: Wires and Patches. Broadband Antennas. Aperture Antennas. Antenna Synthesis. Antennas in Systems and Antenna Measurements. CEM for Antennas: The Method of Moments. CEM for Antennas: Finite Difference Time Domain Method. CEM for Antennas: High-Frequency Methods. Appendices. Index.
...read more
Topics: Dipole antenna (65%), Antenna (radio) (64%), Evolved antenna (61%) ...read more
3,853 Citations
Open access•
01 Jan 2005-
Abstract: The most-up-to-date resource available on antenna theory and design. Expanded coverage of design procedures and equations makes meeting ABET design requirements easy and prepares readers for authentic situations in industry. New coverage of microstrip antennas exposes readers to information vital to a wide variety of practical applications.Computer programs at end of each chapter and the accompanying disk assist in problem solving, design projects and data plotting.-- Includes updated material on moment methods, radar cross section, mutual impedances, aperture and horn antennas, and antenna measurements.-- Outstanding 3-dimensional illustrations help readers visualize the entire antenna radiation pattern.
...read more
Topics: Microstrip antenna (58%), Antenna (radio) (57%)
2,907 Citations
Abstract: A multiplicity of autonomous terminals simultaneously transmits data streams to a compact array of antennas. The array uses imperfect channel-state information derived from transmitted pilots to extract the individual data streams. The power radiated by the terminals can be made inversely proportional to the square-root of the number of base station antennas with no reduction in performance. In contrast if perfect channel-state information were available the power could be made inversely proportional to the number of antennas. Lower capacity bounds for maximum-ratio combining (MRC), zero-forcing (ZF) and minimum mean-square error (MMSE) detection are derived. An MRC receiver normally performs worse than ZF and MMSE. However as power levels are reduced, the cross-talk introduced by the inferior maximum-ratio receiver eventually falls below the noise level and this simple receiver becomes a viable option. The tradeoff between the energy efficiency (as measured in bits/J) and spectral efficiency (as measured in bits/channel use/terminal) is quantified for a channel model that includes small-scale fading but not large-scale fading. It is shown that the use of moderately large antenna arrays can improve the spectral and energy efficiency with orders of magnitude compared to a single-antenna system.
...read more
Fig. 3. Same as Figure 2, but with Eu = 5 dB. 
Fig. 2. Spectral efficiency versus the number of BS antennas M for MRC, ZF, and MMSE processing at the receiver, with perfect CSI and with imperfect CSI (obtained from uplink pilots). In this example K = 10 users are served simultaneously, the reference transmit power is Eu = 20 dB, and the propagation parameters were σshadow = 8 dB and ν = 3.8. 
Fig. 1. Lower bounds and numerically evaluated values of the spectral efficiency for different numbers of BS antennas for MRC, ZF, and MMSE with perfect and imperfect CSI. In this example there are K = 10 users, the coherence interval T = 196, the transmit power per terminal is pu = 10 dB, and the propagation channel parameters were σshadow = 8 dB, and ν = 3.8. 
Fig. 8. Same as Figure 6, but for a multicell scenario, with L = 7 cells, and coherence interval T = 196. 
Fig. 6. Energy efficiency (normalized with respect to the reference mode) versus spectral efficiency for MRC and ZF with imperfect CSI. The reference mode corresponds to K = 1,M = 1 (single antenna, single user), and a transmit power of pu = 10 dB. The coherence interval is T = 196 symbols. For the dashed curves (marked with K = 1), the transmit power pu and the fraction of the coherence interval τ/T spent on training was optimized in order to maximize the energy efficiency for a fixed spectral efficiency. For the green and red curves (marked MRC and ZF; shown for M = 50 and M = 100 antennas, respectively), the number of users K was optimized jointly with pu and τ/T to maximize the energy efficiency for given spectral efficiency. Any operating point on the curves can be obtained by appropriately selecting pu and optimizing with respect to K and τ/T . The number marked next to the × marks on each curve is the power pu spent by the transmitter.
+ 4
Topics: Fading (57%), Spectral efficiency (55%), Multi-user MIMO (55%) ...read more
2,568 Citations
Abstract: We investigate the effects of fading correlations in multielement antenna (MEA) communication systems. Pioneering studies showed that if the fades connecting pairs of transmit and receive antenna elements are independently, identically distributed, MEAs offer a large increase in capacity compared to single-antenna systems. An MEA system can be described in terms of spatial eigenmodes, which are single-input single-output subchannels. The channel capacity of an MEA is the sum of capacities of these subchannels. We show that the fading correlation affects the MEA capacity by modifying the distributions of the gains of these subchannels. The fading correlation depends on the physical parameters of MEA and the scatterer characteristics. In this paper, to characterize the fading correlation, we employ an abstract model, which is appropriate for modeling narrow-band Rayleigh fading in fixed wireless systems.
...read more
Topics: Fading distribution (66%), Fading (62%), Channel state information (61%) ...read more
2,522 Citations