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It is well known that the bandwidth of a microstrip antenna can be increased by overlaying a parasitic element or director. A radioelectric model was presented [l] to explain this property in the case of a rectangular patch antenna. The purpose of this communication is a generalization of the analysis for an arbitrary shape symmetrical patch antenna coupled with a director. A quasi TEM two coupled...
We have proposed and discussed a dual-spiral slot as a circularly polarized radiation element with a simple feeding system [1]. The dual-spiral slot located in the x-y plane, as shown in Fig. 1(a), has different radiation patterns in the x-z and y-z planes, due to its dual-element configuration. When the same radiation pattern is required in the x-z and y-z planes, the dual configuration is changed...
Effects of mutual coupling in arrays of printed strip dipoles and rectangular microstrip antenna, and the mutual impedance effects for two printed dipoles in broadside, collinear and echelon arrangement have been reported in the literature. In this paper, the authors consider the case of skewed microstrip antennas. This initial study is to help analyze a circular arrangement of N patches with arbitrary...
Different radiation formulas are compared for the case of a rectangular microstrip patch antenna, either on an infinite substrate (Fig. la) or on an infinite ground plane with the substrate truncated at the boundary of the patch (Fig. lb). For both the infinite and truncated substrate cases the electric current model is compared with the magnetic current model using the dominant-mode assumption. A...
A moment method solution for the Electric Field Integral Equation is used to analyse a rectangular patch air-dielectric microstrip antenna on an infinite size ground plane. The patch surface is modelled by surface patch modes. The mutual impedance between the surface patch modes are calculated using a simple formula. The effect of the fringing field at the edges of the rectangular patch is derived...
Electromagnetically coupled (EM fed) microstrip patches have their feed structure fabricated on a thin substrate located between the patch antenna and its ground plane as shown in Figure 1. This dual layer design has two main advantages over conventional single layer microstrip antennas. First, spurious radiation from the feed network can be reduced by decreasing the height and increasing the dielectric...
A dual polarized microstrip patch array is being developed for use in a polarimetric synthetic aperture radar system. This paper presents an analysis and empirical results for the linear array in the elevation plane which will be replicated 96 times to form a 2.5m × 0.5m planar array. The vertical and horizontal polarizations of the linear array are series and aperture fed respectively. As a result...
The NASA Deep Space Network (DSN) is constructing a new 34-meter research and development antenna as a precursor to introducing beamwaveguide antennas and Ka-band frequencies into the operational network. The basic design of the center-fed beamwaveguide is shown in Figure 1. It consists of a beam magnifier ellipse in a pedestal room located below ground level that transforms a JPL standard 22-dB gain...
Design and experimental results of an L-band active array for mobile satellite communication antennas are presented in this paper. A receive feed array consisting of seven active modules is breadboarded. Each module consists of a circularly polarized radiating element, a stripline filter, a low-noise amplifier, a variable attenuator and a variable phase shifter. The output ports of the active modules...
Advanced multi-function Ku-band feed systems for satellite or earth station application require a number of operational features such as wide bandwidth, dual polarization, frequency reuse and polarization re-orientation. When built for satellite application, the feed system must also be compact, environmentally rugged and light weight. The realization of such a feed system calls for the development...
The space segment of a mobile satellite communication system must provide high power densities (EIRP) on the ground to allow mobiles with small low gain antennas to communicate. With the emerging high power multiple channel mobile communication satellites, the interference caused by Passive Intermodulation (PIM) is now recognized as an important spacecraft performance parameter. Several antenna concepts...
A mechanically-scanned offset reflector with a multiple feed array is proposed as a feasible configuration for a radiometric antenna. The antenna is designed to operate over six different frequency bands, ranging from 6.80 GHz to 90.0 GHz, and is optimized to simultaneously satisfy the requirements on beam footprint overlap, sidelobe and cross-polar levels. Computed electrical performance is presented...
Satellite communication antennas commonly employ beamforming networks (BFN's) which hitherto have been realized with discrete components. This paper presents two alternative BFN technologies developed at Spar Aerospace, namely integrated waveguide and integrated TEM-line which advantageously replace the discrete component technology. The integrated feed concept is presented together with design examples...
New method is applied on linear phased array in order to increase the inter-element separation. The method is based on using elements of scan capability, where the element pattern has a null at specified direction. Dual mode horns are used here, where the position of the element pattern null is controlled by the relative amplitude and phase of the second mode. In this case if the element pattern null...
A radial line slot antenna (RLSA) is a kind of slotted waveguide array for DBS reception [1][2]. It is free of conductor loss and the aperture efficiency is more than 75%, twice as high as conventional planar antennas [3]. Those performances have been realized for double-layered RLSAs with uniform slot length.
Reflector configurations suitable for a multibeam EHF satellite communication receive antenna are reviewed in this paper. Four different antenna systems have been studied and their relative performances are compared. Computer simulations have been performed to analyze the co-polar and cross-polar gain contours of the antennas and the results are discussed.
The software EMsim™∗ has a graphical shell and a field theory “engine” WATMIC. This paper discusses the adjustments to the engine to improve the accuracy to 1 % error or less. The only limitation for new WATMIC is that it does not account for surface wave of substrates thicker than 0.05λd (in the substrate).
We propose to investigate printed circuit applicators for biomedical applications: the microstrip-microslot and the microstrip applicators laid on multilayered lossy media and covered or not with a superstrate. We want to get their fundamental characteristic parameters: the complex propagation constant (relative effective permittivity ∊reff, attenuation α), the associated characteristic impedance...
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