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 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 0 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 An Eight element SBF Fan beam Array written by Hermann W. Ehrenspeck and published by . This book was released on 1974 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eight short backfire (SBF) elements aligned on a common planar reflector form a highly efficient fan-beam array capable of yielding a maximum gain of approximately 24 dB. The influence of parameter variations on the array patterns and directivity was experimentally determined by varying the frequency. Normalized design parameters for highest efficiency and for circular polarization capability are tabulated. All array dimensions are given in wavelengths so that each application can easily be scaled for any desired frequency.
Download or read book Short backfire Arrays written by Hermann W. Ehrenspeck and published by . This book was released on 1971 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short-backfire (SBF) antennas can be simply converted into highly directive and efficient array elements. Each SBF element is the equivalent of four to six dipole elements of conventional multielement arrays. Models of two-, four-, and eight-element SBF arrays have yielded gains of 17, 19, and 22 dB, respectively. Radiation patterns are presented, including the sum and difference patterns in the two major planes (E and H), as well as those for diagonal cuts at plus or minus 45 degrees. All physical dimensions are given in wavelengths so that each model can be easily scaled for any desired frequency. (Author).
Download or read book The Four element SBF Array written by Hermann W. Ehrenspeck and published by . This book was released on 1971 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four-element short-backfire (SBF) arrays have been shown to yield maximum gains of approximately 20 dB. The influence of parameter variations on the array patterns has been experimentally determined. Specific parameter values required to yield certain pattern characteristics--for example, highest gain, lowest sidelobe level, equal half-power beamwidth, or equal beam shapes in both the E and H planes--have been established. Tables of the normalized design parameters are given for construction purposes. All array dimensions are indicated in wavelengths so that each model can easily be scaled for any desired frequency range. (Author).
Download or read book An SBF Array for Reception of Atmospheric Noise written by J. A. Strom and published by . This book was released on 1974 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A four-element short-backfire array was designed, fabricated, and experimentally tested for use as a receiving antenna of low level atmospheric noise at 920 MHz. A complete set of design dimensions is presented as well as the resultant radiation patterns and frequency curves of sidelobe levels, half-power beamwidths, and input impedance. The effects of variations on the size and shape of the main reflector are discussed, especially when efficient operation with low sidelobes or high gain is of prime importance. Supporting data and tables of optimum design dimension are also provided for future VHF or UHF antenna applications in the gain range of 17 to 20 dB.
Download or read book A Sixteen element SBF Array written by Hermann W. Ehrenspeck and published by . This book was released on 1972 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sixteen-element short-backfire arrays have been shown to yield maximum gains of approximately 25 dB. The influence of parameter variations on the array patterns and directivity has been experimentally determined by varying the frequency. A table of the normalized design parameters for an area efficiency of approximately 90 percent is given for construction purposes. All array dimensions are indicated in wavelengths so that each application can easily be scaled for any desired frequency range.
Download or read book Instrumentation Papers written by and published by . This book was released on with total page 292 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 Oversized Elements for High Efficiency Extremely High Frequency Boresight Array written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High gain, planar array antennas which operate at millimetre wave frequencies, and can be mass produced at low cost, are desired by industry. The design of such arrays continues to be academically challenging. A literature review was conducted covering patents and papers describing antenna arrays either operating at, or suitable for operation at, millimetre wave frequencies. Four presently under exploited technology types were identified. Two of the under exploited technologies were investigated. Both small and medium sized arrays of non-radiating edge fed microstrip patches were built up in a consistent process. The design of the patch and 1 x 2 subarray were shown to affect the radiation pattern behaviour of 16 x 16 arrays. The placement of nulls in the 2 x 2 subarray radiation patterns proved critical to the mitigation of grating lobes, which were a source of directivity loss. A considerable difference in directivity characteristics across 10% bandwidth was found between in phase and 180 feeding within the 2 x 2 subarrays. An optimised 180 fed 4 x 4 subarray presented an improvement over prior work. Changing the boundary conditions at the juncture of the base and rim of the cavity of short backfire antennas was found to alter the directivity. Large diameter short backfire antennas with choked, inclined and curved junctures produced high directivity. A readily machinable design was used in a small array, to demonstrate its utility as a high aperture efficiency array element. The results are of importance to the future development of low cost, planar or quasi-planar antenna arrays, particularly at millimetre wave frequencies.
Download or read book Oversized Elements for High Efficiency Extremely High Frequency Boresight Array written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Short backfire Arrays written by Hermann W. Ehrenspeck and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short-backfire (SBF) antennas can be simply converted into highly directive and efficient array elements. Each SBF element is the equivalent of four to six dipole elements of conventional multielement arrays. Models of two-, four-, and eight-element SBF arrays have yielded gains of 17, 19, and 22 dB, respectively. Radiation patterns are presented, including the sum and difference patterns in the two major planes (E and H), as well as those for diagonal cuts at plus or minus 45 degrees. All physical dimensions are given in wavelengths so that each model can be easily scaled for any desired frequency. (Author)
Download or read book Proceedings of the OAR Research Applications Conference written by and published by . This book was released on 1967 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings written by and published by . This book was released on 1967 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography with Abstracts of AFCRL Publications from 1 April to 30 June 1971 written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1971 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Middle Atmosphere Program written by and published by . This book was released on 1981 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 952 pages. Available in PDF, EPUB and Kindle. Book excerpt:
