Telecommunication
elham sharifi; Arash Ahmadi; Mohammad Fazaelifar
Abstract
The antenna of a high throughput satellite payload should generate multiple spot beams simultaneously to provide frequency reuse by creating cellular coverage for the satellite. The phased array antenna is a proper option for this application. In geostationary orbit, the satellite field of view is limited, ...
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The antenna of a high throughput satellite payload should generate multiple spot beams simultaneously to provide frequency reuse by creating cellular coverage for the satellite. The phased array antenna is a proper option for this application. In geostationary orbit, the satellite field of view is limited, and dividing it to several tight beams poses many challenges to the antenna design. The large dimensions of the radiating aperture, high number of radiant elements, the need for dividing the array to several sub-arrays, which lead to appearance of grating lobes, and the orthogonality of the beams with tiny angular distance are the challenges of the antenna design. In this article, a multiple beam phased array antenna in Ka-band with microwave beam forming network is synthesized and designed to meet aforementioned challenges. The sub-beam technique has been used for decreasing the array dimensions. For eliminating the grating lobes, the array has been divided into interleaved sub-arrays in two dimensions. A new beam forming network which can generate 20×20 simultaneous orthogonal beams in an area with coverage widths of 10˚ and 8.8˚ in longitude and latitude directions has been devised in this paper.
Telecommunication
Sahar Abdi; Morteza Cheheltanan
Abstract
A wideband high-gain microstip patch array antenna for high resolution synthetic aperture radar applications is presented. The antenna operation frequency is in the X-band. The antenna structure is a four-layer configuration consisting of radiating patches, slots, coupling cavities, and a corporate feeding ...
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A wideband high-gain microstip patch array antenna for high resolution synthetic aperture radar applications is presented. The antenna operation frequency is in the X-band. The antenna structure is a four-layer configuration consisting of radiating patches, slots, coupling cavities, and a corporate feeding network, which in turn is fed by a coaxial probe. The increased frequency bandwidth of the radiating patch is achieved by employing a square slot, which appears as a cavity for it, and improves the gain and impedance bandwidth of the antenna array by isolating the patch feeding slot and eliminating the mutual coupling effect. The whole antenna structure is fabricated by using a combination of the milling process and printed circuit technology. Measurement results show a relative gain bandwidth of more than 10%, in which the antenna gain is measured above 28.8 dBi over the frequency band of more than 1 GHz. Moreover, the relative impedance bandwidth of the antenna for VSWR>2 is more than 16%.
