Showing papers on "Fresnel zone antenna published in 1970"
Book•
01 Jan 1970
TL;DR: In this paper, the authors present an analysis of reflector antennas covering electromagnetic field equations, computer aided design, and computer-aided design of reflectors for reflector antenna arrays.
Abstract: Monograph on analysis of reflector antennas covering electromagnetic field equations, computer aided design, etc
148 citations
TL;DR: In this paper, the behavior of log-periodic dipole (LPD) antennas, which are compressed along the transmission-line axis, was studied both experimentally and theoretically, and it was found that compressed LPD antennas are efficient, of low gain, and frequency independent.
Abstract: The behavior of log-periodic dipole (LPD) antennas, which are compressed along the transmission-line axis, is studied both experimentally and theoretically. Compressed LPD antennas are found to be efficient, of low gain, and frequency independent. With compression, the radiation pattern approaches dipole-like behavior and the bandwidth increases slightly. It is also found that LPD antennas exhibit anomalous frequency-dependent behavior in narrow bands of frequencies ( \approx 1/8 of a log period in width) when a reactive termination is used and when the scaling factor \tau is below about 0.92-0.93.
36 citations
17 citations
Patent•
24 Jun 1970
TL;DR: In this article, a variable electro-optic Fresnel zone plate with a characteristic that varies as a function of an applied electric field is described, and means for applying to that medium an electric field whose intensity varies in a pattern of alternate high intensity and low intensity bands.
Abstract: Apparatus is disclosed including a variable electro-optic Fresnel zone plate having an electro-optic medium with a characteristic that varies as a function of an applied electric field, means for applying to that medium an electric field whose intensity varies in a pattern of alternate high intensity and low intensity bands, and means for demodulating radiation modulated by that characteristic of the medium to produce a Fresnel zone plate pattern of radiation
11 citations
Patent•
10 Jul 1970
TL;DR: In this paper, a semiconducting microcircuit element with a Fresnel optical system was combined with a compact integrated structure for the transformation of radiant energy into electric energy or vice versa.
Abstract: This invention concerns improved structures for the transformation of radiant energy into electric energy or vice versa. The improvement consists of combining a semiconducting microcircuit element with a Fresnel optical system into a compact integrated structure.
10 citations
31 May 1970
TL;DR: In this paper, the authors evaluate large reflector antennas including effects of primary reflector astigmatism and its measurement through diffraction, and show that the effect of the primary reflectors on the measurement of diffraction is negligible.
Abstract: Evaluation of large reflector antennas including effects of primary reflector astigmatism and its measurement through diffraction
5 citations
Patent•
09 Jul 1970TL;DR: A conducting or absorbing ground clutter fence at least partly encircles an antenna to block electromagnetic energy in a horizontal band having a vertical height equal to one-half the diameter of the first Fresnel zone of the antenna and furthermore, a vertical portion thereof completely within the first fresnel zone as discussed by the authors.
Abstract: A conducting or absorbing ground clutter fence at least partly encircles an antenna to block electromagnetic energy in a horizontal band having a vertical height equal to one-half the diameter of the first Fresnel zone of the antenna and, furthermore, having a vertical portion thereof completely within the first Fresnel zone
4 citations
4 citations
TL;DR: In this paper, a unique unidirectional octave-bandwidth reflector type circularly polarized antenna is described which uses crossed parallel connected conical dipoles operated near second resonance.
Abstract: A unique unidirectional octave-bandwidth reflector type circularly polarized antenna is described which uses crossed parallel connected conical dipoles operated near second resonance. The impedance characteristics of the antennas together with added series reactances gives the desired approximately quadrature current relation between the two dipoles. The axial ratio does not exceed 2 to 1.
4 citations
01 Jan 1970
4 citations
01 Apr 1970
TL;DR: Sidelobe suppression for satellite reflector antennas by heavy taper, blockage compensation and active zone techniques, noting net antenna gain enhancement was discussed in this paper, where the authors noted net antenna gains enhancement.
Abstract: Sidelobe suppression for satellite reflector antennas by heavy taper, blockage compensation and active zone techniques, noting net antenna gain enhancement
01 May 1970
01 Jan 1970
01 Jan 1970
01 Jan 1970