Coaxial cavity waveguide antennas excited by stacked circular microstrip patches for use as prime‐focus reflector feeds |
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| Authors: | Zahra A Pour Saeed I Latif Mohammad Qudrat‐E‐Maula Lotfollah Shafai |
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| Affiliation: | 1. Department Electrical and Computer Engineering, University of Alabama at Huntsville, Huntsville, Alabama, USA;2. Department Electrical and Computer Engineering, University of South Alabama, Mobile, Alabama, USA;3. Global Skyware, 1315 Outlet Center Drive, Smithfield, North Carolina, USA;4. Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manibota, Canada |
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| Abstract: | A coaxial cavity antenna excited by a stacked circular microstrip antenna is investigated as a feed for prime‐focus parabolic reflector antennas. The radiation pattern of the proposed cavity‐backed antenna is saddle shaped, which widens the ?10 dB beamwidths and increases the reflector efficiency especially for deep reflectors with small focal length‐to‐diameter ratios. With a single‐probe feed, the co‐polar radiation pattern is slightly asymmetric in the E‐plane, but is made symmetric by a differential feeding technique, using two probes. The impedance bandwidth of the proposed feed antenna is 20%. The antenna was fabricated and tested, and it exhibited good agreement between simulation and measurement results. The gain factor of the feed was also studied with a circular‐symmetric reflector and provided a gain factor of 79% at f/D = 0.375. This type of feed can be used as an alternative to conventional horn or waveguide feeds, where reduced size and light‐weight are desirable with added advantage of easy integration with electronics. |
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| Keywords: | coaxial cavity microstrip patch primary feeds reflector antennas waveguide |
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