Showing papers on "Reflective array antenna published in 1967"
TL;DR: In this paper, a Van Atta antenna array, which has a major lobe of the reradiated field in a direction retrograde to that of the incident wave for arbitrary directions of incidence, is analyzed in terms of the scattering matrix of the network interconnecting the antennas.
Abstract: A Van Atta antenna array, which has a major lobe of the reradiated field in a direction retrograde to that of the incident wave for arbitrary directions of incidence, is analyzed in terms of the scattering matrix of the network interconnecting the antennas.
95 citations
01 Jan 1967
TL;DR: In this article, the basic properties of cylindrical antennas and arrays are reviewed from the time of Hertz to the present, including the effect of mutual coupling on them, the driving point admittances, and the field patterns.
Abstract: Progress in understanding the basic properties of cylindrical antennas and arrays is reviewed from the time of Hertz to the present. The infinitesimal doublet, antennas with assumed sinusoidal currents, boundary-value solutions and recently developed approximations for isolated antennas, circular, curtain, and Yagi arrays are discussed and illustrated. It is concluded that useful quantitative methods for treating cylindrical antennas of finite cross section and arrays of such antennas are now available. These take account of actual distributions of current and the effects of mutual coupling on them, the driving-point admittances, and the field patterns.
84 citations
45 citations
01 Jun 1967
TL;DR: In this article, the two-antenna method is considered to be essentially an insertions-loss measurement (with many additional problems and sources of error), and this concept is used to derive a working formula that is suitable for high-accuracy gain measurements.
Abstract: To calibrate antennas for state-of-the-art field-strength measurements above 1 GHz, standard antennas are needed that have gain values known to within ±0.1 dB. Since this requirements exceeds the verified accuracy of calculated gain values, these standards must be established by making absolute gain measurements. The discussion primarily concerns absolute gain measurements for horn antennas by the two-antenna method. However, much of the discussion is pertinent to high-accuracy field-strength measurements in general. The two-antenna method is considered to be essentially an insertions-loss measurement (with many additional problems and sources of error), and this concept is used to derive a working formula that is suitable for high-accuracy gain measurements. The two most intractable problems-- insufficient antenna separation and multipath interference--are discussed in detail. Some important experimental details are included that have previously been overlooked or inadequately discussed, and it is concluded that previous error estimates of less than ±0.1 dB for horn-gain measurements have been somewhat optimistic. To facilitate the design and evaluation of high-accuracy gain measurements, some simple terms, concepts, and formulas are provided that are useful in analyzing multipath interference.
41 citations
TL;DR: In this paper, a solution for the active impedance and current distribution on a cylindrical antenna in a uniform, infinite, planar, or collinear array is given for the case in which the distance in the collincear direction between the ends of adjacent elements is small.
Abstract: A solution is given for the active impedance and current distribution on a cylindrical antenna in a uniform, infinite, planar, or collinear array. The analysis is applicable to the case in which the distance in the collinear direction between the ends of adjacent elements is small. The current distribution on the collinear array is found by relating the antenna current and electric-field variation on the cylindrical surface of infinite length which contains the array. This analysis is then extended to consider a planar array. Results obtained are applicable to any combination of element length and array phasing, for arrays with or without a ground plane. Comparisons with other investigations based upon sinusoidally distributed currents reveal substantial discrepancies for some configurations.
15 citations
15 citations
14 citations
12 citations
01 Mar 1967
TL;DR: In this paper, the authors describe an experimental C-band phased array antenna composed of eight subarrays which may be arranged in several configurations to investigate the effects of a full array.
Abstract: : The ability to rapidly scan a highly directive antenna beam has been made possible by recent advances in the art of microwave phase shifting. This report describes an experimental C-band phased array antenna. The antenna is composed of eight subarrays which may be arranged in several configurations to investigate the effects of a full array. Each subarray contains a reactive power divider, 48 ferrite phase shifters and their electronic drivers, and a radiating structure. The radiating structure has been designed to provide some compensation for impedance variation with scanning. The design and fabrication of the components are discussed in detail, and test results of the array are presented and analyzed.
Journal Article•
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TL;DR: In this paper, the authors derived the radio gain between two short electric dipole antennas in free space and showed that when the antennas are above and parallel to a perfectly conducting plane, radio gain approaches a constant as the antennas approach the ground.
Abstract: The radio gain or power transfer between two short electric dipole antennas in free space is derived. When the antennas are above and parallel to a perfectly conducting plane, the radio gain approaches a constant as the antennas approach the ground. As the antennas are raised the radio gain is approximately proportional to the square of the product of the antenna heights. At greater heights the interference between the direct and reflected wave causes the radio gain to oscillate. At low antenna heights on vertical polarization the radio gain is the same as in free space. As the antennas are raised it increases and oscillates about four times its free space value. At greater heights the oscillation of the radio gain has greater amplitude. The maxima on vertical polarization occur at the same height as the minima on horizontal polarization and vice versa. For antennas above an imperfectly conducting plane, the radio gain decreases indefinitely as the antennas are lowered and depends upon the polarization and whether the antennas are electric or magnetic dipoles. Numerical values are given for \sigma\lambda = 1 . Vertical loop antennas give greater radio gain for ground wave propagation.
01 May 1967
TL;DR: In this paper, the authors present results of studies, investigations, and technique developments which will be useful in future HF long range radar applications, including the development of a multifilar helical contrawound antenna which may be suitable as the wideband radiating element for large HF array antennas.
Abstract: : This report presents results of studies, investigations, and technique developments which will be useful in future HF long range radar applications. This report covers the development of a multifilar helical contrawound antenna which may be suitable as the wideband radiating element for large HF array antennas.
01 Jan 1967
12 Dec 1967
TL;DR: In this paper, a general method for designing circular array antennas to obtain quasi-omnidirectional patterns was proposed, based on the design of the antenna array itself and the antenna configuration.
Abstract: General method for designing circular array antennas to obtain quasi-omnidirectional patterns
TL;DR: A statistical formalization of the interpretation of the received signal levels permits that combination of receiving and transmitting antenna orientations to be chosen which most probably represents the aligned combination.
Abstract: A procedure is described for aligning transmitting and receiving antennas in a communications link with a minimum number of positionings of the antennas. A statistical formalization of the interpretation of the received signal levels permits that combination of receiving and transmitting antenna orientations to be chosen which most probably represents the aligned combination. A criterion is also developed for estimating the goodness of the alignment.