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In this paper, an offset reflector antenna with dual-beam and dual-polarization characteristics is developed to provide the angular diversity function for troposcatter communication system. The antenna system consists of a parabolic reflector and a dual-beam feed. For the dual-beam feed, two identical Ku-band feed elements are arranged side by side to generate two beams toward the reflector. The two beams are substantially nonoverlapping. The feed element is composed of a dielectric rod, a square waveguide, and an ortho-mode transducer. The dielectric rod is effective in reducing the beamwidth of the feed and providing more tapered illumination on the reflector in order to increase the antenna gain. Moreover, the developed antenna is able to produce two independent beams with the vertical and horizontal polarizations. The antenna was fabricated and tested with good agreement between the simulation and measurement results. The measured voltage standing wave ratios of the four feed ports are less than 1.5:1, and the beam separation angle is not more than 0.7° or about one time half-power beamwidth, and the antenna gain is higher than 45 dBi over the operating band from 14.5 to 15.35 GHz. [ABSTRACT FROM AUTHOR]

A new quad-layer partially reflective surface (PRS) is presented in this letter for dual-polarized Fabry–Perot (FP) cavity antennas with an improved gain bandwidth. Four layers of metallic square rings are printed on each side of two dielectric substrates separated by an air gap of about λ/27 (λ is the wavelength in the open air) at 5.5 GHz. The total profile of the FP cavity is about λ /2. By properly choosing the dimensions of square rings and the distance between the two substrates, the phase of the reflection coefficient of the PRS increases with the operating frequency, demonstrating a broadband property. In order to validate the performance of the proposed PRS, a dual-polarized FP antenna is designed, which has peak realized gains of 14.7 and 15.5 dBi with 1 dB bandwidths of more than 10% for two polarizations. Furthermore, the input reflection coefficients are lower than −15 dB in the 5.05–5.8 GHz band, and the isolation of the dual-polarized modes is more than 30 dB. [ABSTRACT FROM AUTHOR]

The design of a novel partially reflective surface (PRS) antenna with the capability of beam steering is presented in this paper. The beam steering is realized by employing a reconfigurable PRS structure to achieve a changeable reflection phase as well as using a phased array as the source to excite the PRS antenna. A prototype antenna including the biasing network is fabricated and measured. It achieves a consistent beam steering from – 15° to 15° with respect to the broadside direction across an overlapped frequency range from 5.5 to 5.7 GHz with measured realized gains over 12 dBi. Good agreement between the simulated and measured results for the input reflection coefficients and radiation patterns is achieved, which validates the feasibility of the design principle. Compared with other beam steering PRS antennas, the proposed one enables a larger beam steering angle with comparable gains, requires a simpler biasing network, and is more compact. [ABSTRACT FROM PUBLISHER]