Download or read book The Backfire Antenna written by Hermann W. Ehrenspeck and published by . This book was released on 1965 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Backfire Antenna written by Francis J. Zucker and published by . This book was released on 1966 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High gain UHF Backfire Antenna for Communications Telemetry and Radio Astronomy written by Hermann W. Ehrenspeck and published by . This book was released on 1967 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book A Dielectric rod Backfire Antenna written by J. A. Strom and published by . This book was released on 1969 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A backfire antenna is described which incorporates a dielectric slow-wave structure in place of the parasitic directors of earlier models. Using previously investigated optimum dimensions, this antenna uses new techniques of energizing in a cross polarized sense. Measurements of far-field patterns, directivity, and isolation between primary planes are given. (Author).
Download or read book The Short backfire Antenna written by Hermann W. Ehrenspeck and published by . This book was released on 1965 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Backfire Antenna a New Type of Directional Line Source written by Hermann W. Ehrenspeck and published by . This book was released on 1961 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: A description is given of the backfire antenna, a new type surface-wave radiator which consists of an ordinary endfire structure (Yagi, dielectric rod, and so forth) terminated by a plane reflector. The surface wave launched at the feed travels along the endfire structure until it impinges on the reflector; it then travels back toward the feed and radiates into space in a direction opposite to that of normal endfire operation. The gain of the backfire antenna is between 4 and 6 db higher than that of an ordinary endfire antenna of the same length; conversely, to achieve the same gain, the backfire antenna needs to be only between 1/4 to 1/3 as long as the ordinary endfire antenna. The side and back lobes can be kept extremely low. The backfire antenna will have wide application in cases in which the transverse dimension of the reflector does not violate ringe low-silhou t requirem nt . (Author).
Download or read book The Short backfire Antenna as an Element for High gain Arrays written by Hermann W. Ehrenspeck and published by . This book was released on 1971 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The short backfire (SBF) antenna consisting of a large reflector illuminated by a dipole feed and smaller disk reflector produces a gain of 15 dB above isotropic. As an array element it has been efficiently adapted for various configurations of high-gain antennas producing gains of up to 25 dB, with a single SBF element capable of replacing four to six elements of a conventional multidipole array. Farfield patterns and directivity measurements are presented for a single element and for a twin element mounted on a common reflector. Optimized dimensions for both cases are discussed for possible application to more complex types of antennas.
Download or read book The Research on Short Backfire Antenna written by C. L. Lin and published by . This book was released on 1983 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Backfire Antenna Theory and Design written by Amer Tawfeeq Abed and published by LAP Lambert Academic Publishing. This book was released on 2013-01 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: In last years, there has been an increasing need for high gain wide band directional antennas in some wireless applications, mobile communication systems and other applications. The backfire antenna may become one of the most competitive candidates for these applications, because of its high gain and simple structure. The backfire antenna principle is a highly effective technique for improving the pattern characteristics of an antenna. When the space between the reflectors(from 0.5 to ) the backfire antenna called short backfire antenna(SBFA) and its called long backfire antenna(LBFA) when the space between reflectors greater than the wave length ( )."
Download or read book Blunschi Jules 1896 1967 written by and published by . This book was released on 1951 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zeitungsausschnitte (1951-1967).
Download or read book High gain UHF Backfire Antenna for Communications Telemetry and Radio Astronomy written by H. W. Ehrenspeck and published by . This book was released on 1967 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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)
Download or read book The Modified Short Backfire Antenna written by Finn A. Hass and published by . This book was released on 1971 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements have shown it possible to increase the gain of the short backfire antenna significantly in different ways: (1) By increasing the size of the reflectors. (2) By placing extra reflectors in multiples of a half wavelength from the surface wave reflector. (3) By placing a quarter-wave ring in front of the surface of the wave reflector. The surface of the ring is perpendicular to the reflector and the ring has the same diameter as the reflector. The distance between the ring and the reflector giving maximum gain depends on the size and the number of the reflectors. The choice of parameters (size of reflectors) was based on numerical calculations using a theory developed by Drago Neilsen and Pontoppidan at the contracting laboratory. Measurements have shown a decrease in impedance bandwidth product. The levels of the backward lobe and the side lobes are increased, too, but the levels are kept at an acceptable height due to the influence of the quarter-wave ring. The beamwidths in E- and H-plane tend to be equal with increasing gain. This is an advantage if circular polarization is wanted. The modified short backfire antenna has a higher gain than any other backfire antenna of the same size (same length and diameter of the surface wave reflector). The antenna is easy to construct. (Author).
Download or read book Influence of Variation of Backfire Antenna Parameters 1 written by Erik Drago Nielsen and published by . This book was released on 1970 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large number of numerical results for Yagi backfire antennas are presented, from which the influence of a variation of the antenna parameters may be deducted. The results were obtained by means of a previously described theory for backfire antennas with dipole elements, and the numerical computations were carried out on a digital computer. Samples of the numerical results were compared with experimental results obtained in a radio anechoic chamber. Finally, the influence of small changes in the general Yagi backfire antenna structure, such as changing the single dipole reflector elements into a half-transparent or solid conducting plate or changing the array of equally long dipole director elements into a tapered array, was investigated. (Author).
Download or read book Influence of Variation of Backfire Antenna Parameters II Short Backfire Antenna written by Erik Drago Nielsen and published by . This book was released on 1970 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large number of numerical and experimental results showing the influence of a variation of the antenna parameters on the radiation properties of a short-backfire antenna are presented. These results may be very useful for the design of such antennas. The numerical results were calculated on a digital computer using a previously published theory for backfire antennas with dipole elements. The experimental results were measured in a radio anechoic chamber. Other numerical results were obtained, which show that the radiation properties of the short-backfire antenna correspond to those of open resonators. Finally, a number of computations were carried out in order to investigate the possibility of applying the short-backfire antenna as the excitation system of a Yagi antenna. (Author).
Download or read book The Short Backfire Antenna A Numerical Physical Optics Study of Its Characteristics written by Tsing-Zone Hsieh and published by . This book was released on 1971 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical-physical optics method is applied to study the circuit (impedance) and radiation characteristics of the short-backfire antenna. This radiator, developed through extensive experimentation by AFCRL, consists of a dipole exciter located between a large rimmed reflector and a small secondary reflector. It has wide bandwidth and high directivity comparable to sophisticated reflector antennas. In the numerical-physical optics method, the following steps are followed: (1) a set of coupled integral equations for the currents excited in the dipole and on the surface of the secondary reflector are formulated and solved numerically, assuming for this step that the large reflector is infinite; (2) the surface currents of the large reflector are approximated by a truncated form of those calculated for the infinite conducting sheet; (3) the radiation field maintained by the currents of the steps (1) and (2) is calculated; and (4) a diffracted field correction is made to account for the finite dimensions of the large reflector and its rim. This method has the advantage, relative to earlier studies, that it can successfully predict the antenna's circuit characteristics. Excellent results are obtained for both square and circular geometries. Comparison is made with experimental measurements made by AFCRL. (Author).
Download or read book Investigation of Backfire Antenna written by Ngo The Hoanh and published by . This book was released on 1968 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Handbook of Antenna Design written by Alan W. Rudge and published by IET. This book was released on 1982 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the fundamental background theory and analytical techniques of antenna design. It deals with a very wide range of antenna types, operating from very low frequencies to millimetre waves.
