The Backfire Antenna
Author : Hermann W. Ehrenspeck
Publisher :
Page : 10 pages
File Size : 31,21 MB
Release : 1965
Category : Antennas (Electronics)
ISBN :
Author : Hermann W. Ehrenspeck
Publisher :
Page : 10 pages
File Size : 31,21 MB
Release : 1965
Category : Antennas (Electronics)
ISBN :
Author : Hermann W. Ehrenspeck
Publisher :
Page : 24 pages
File Size : 17,56 MB
Release : 1967
Category : Antennas (Electronics)
ISBN :
The backfire antenna described combines the structural advantages of a single endfire with the high gain of a reflector antenna. With its principal application in the gain range between 15 and 30 dB where ordinary endfire antennas become impractically long and paraboloidal antennas too expensive, it should prove to be especially advantageous for telemetry and radio astronomy applications in the 100- to 2000-MHz frequency range. The high gain of the backfire is based on the high-amplitude standing-wave field distribution formed between two planar reflectors. The space between the reflectors acts like an open resonating cavity that in basic configuration and function resembles a Fabrey-Perot laser cavity. An S-band model of a 4.0-wavelength backfire produces a gain of 23.5 dB at its optimum frequency, which corresponds to the gain of an equal-size paraboloidal antenna of 60% efficiency. Patterns show a very low side- and backlobe level over a frequency range of 1.25 to 1. Design information for these backfire antennas is given. Compared with an optimized equal-length Yagi, the backfire antenna produces an increase in gain of more than 8 dB. To achieve a gain of this magnitude with an ordinary array, one of two recently built antennas for satellite applications uses 16 Yagis, each 2.0 wavelength long, to produce a gain of 22.4 dB, and another uses 36 cavity-backed slots to produce 21.2 dB. These results emphasize the advantages of the single-element backfire antenna, whose 23.5 dB gain is achieved through a simple structural design that does not depend on the complicated feed systems that are necessary components in multielement arrays. (Author).
Author : Hermann W. Ehrenspeck
Publisher :
Page : 12 pages
File Size : 41,96 MB
Release : 1965
Category : Antennas (Electronics)
ISBN :
Author :
Publisher :
Page : 240 pages
File Size : 19,92 MB
Release : 1966
Category : Aeronautical instruments
ISBN :
Author :
Publisher :
Page : 220 pages
File Size : 33,60 MB
Release : 1962
Category : Science
ISBN :
Author : United States. National Bureau of Standards
Publisher :
Page : 832 pages
File Size : 31,60 MB
Release : 1960
Category : Ionospheric radio wave propagation
ISBN :
Author :
Publisher :
Page : 128 pages
File Size : 34,39 MB
Release : 1962-10
Category : Physical instruments
ISBN :
Author : United States. National Bureau of Standards
Publisher :
Page : 1136 pages
File Size : 27,97 MB
Release : 1959
Category : Radio
ISBN :
Author : J. C. Brown
Publisher : Elsevier
Page : 566 pages
File Size : 14,23 MB
Release : 2013-10-22
Category : Science
ISBN : 1483185923
Electromagnetic Wave Theory, Part 2 contains the proceedings of a Symposium on Electromagnetic Wave Theory held at Delft, The Netherlands in September 1965. The symposium provided a forum for discussing electromagnetic wave theory and tackled a wide range of topics, from propagation in nonlinear media to electromagnetic wave propagation and amplification in solid-state plasmas. Electromagnetic waves in nonlinear transmission lines with active parameters are also considered, along with the phase dependence of maser active material Q-factor on pump intensity and frequency. Comprised of four sections, this volume begins with an analysis of two modes of propagation that are coupled through parametric modulation in nonlinear media. The discussion then turns to symmetry restrictions in nonlinear, non-absorbing, non-dispersive media; nonlinear interaction between two beams of plane electromagnetic waves in an anisotropic medium; radiation in periodically non-stationary media; and electromagnetic wave propagation in time-varying media. Subsequent chapters explore the diffraction of electromagnetic waves by plasma structures; resonant electromagnetic scattering from gyrotropic plasmas; scattering and transmission of electromagnetic waves at a statistically rough boundary between two dielectric media; and developments in wavefront reconstruction. This book will be useful for students, practitioners, and researchers in physics.
Author : Lal Chand Godara
Publisher : CRC Press
Page : 936 pages
File Size : 11,7 MB
Release : 2018-10-03
Category : Technology & Engineering
ISBN : 1420042149
The move toward worldwide wireless communications continues at a remarkable pace, and the antenna element of the technology is crucial to its success. With contributions from more than 30 international experts, the Handbook of Antennas in Wireless Communications brings together all of the latest research and results to provide engineering professionals and students with a one-stop reference on the theory, technologies, and applications for indoor, hand-held, mobile, and satellite systems. Beginning with an introduction to wireless communications systems, it offers an in-depth treatment of propagation prediction and fading channels. It then explores antenna technology with discussion of antenna design methods and the various antennas in current use or development for base stations, hand held devices, satellite communications, and shaping beams. The discussions then move to smart antennas and phased array technology, including details on array theory and beamforming techniques. Space diversity, direction-of-arrival estimation, source tracking, and blind source separation methods are addressed, as are the implementation of smart antennas and the results of field trials of systems using smart antennas implemented. Finally, the hot media topic of the safety of mobile phones receives due attention, including details of how the human body interacts with the electromagnetic fields of these devices. Its logical development and extensive range of diagrams, figures, and photographs make this handbook easy to follow and provide a clear understanding of design techniques and the performance of finished products. Its unique, comprehensive coverage written by top experts in their fields promises to make the Handbook of Antennas in Wireless Communications the standard reference for the field.