A QV-Band Dual-Polarized Cassegrain Reflector Antenna for New Space Satellite Ground Station Applications

This paper presents a high-performance Q/Vband dual-polarized Cassegrain reflector antenna developed for next-generation space communication ground station applications. The antenna operates over the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$37-51.5 \text{GHz}$</tex> frequency range, delivering a gain of 58 dBi, a half-power beamwidth of 0.2 degrees, and sidelobe levels at least 15 dB below the main lobe nominally. The antenna system comprises a 2.4-meter (96-inch) diameter main reflector, a sub-reflector, a feedhorn, and a complex feed network that integrates a linear-to-circular polarizer, an orthomode transducer (OMT), and two frequency diplexers. Due to the electrically large aperture, performance testing was conducted in a newly developed nearfield measurement range capable of characterizing antennas up to 3.0 meters in diameter at frequencies up to 110 GHz. The measured results confirm that the fabricated antenna meets the original design specifications. Achieving the antenna's high performance, along with accurate pattern and gain measurements, involves substantial technical, manufacturing, and testing challenges. These accomplishments represent a state-of-the-art milestone in the design and production of electrically large antennas operating in this frequency range.