Frequency Selective Subreflector Research Articles

An S-/Ka-Band Shared Aperture Tracking Reflector Antenna With Polarization Diversity

A dual-band dual-polarized tracking reflector design approach has been explored, and successfully demonstrated the S- and Ka-band tracking with enhanced performance. The antenna works in Cassegrain mode at Ka-band and the prime focus configuration at S-band. A frequency selective subreflector isolates the two feeds, permits S-band transmission, and reflects the Ka-band signal. The antenna is dual linearly polarized at S-band and dual circularly polarized at Ka-band. It capitulates an impedance bandwidth wider than 23.9% with isolation superior to 24 dB at the S-band ports. At the Ka-band, it also displays an axial ratio ≤3 dB with isolation above 23 dB over the entire operating bandwidth of ≥12.4%. Monopulse tracking bandwidths of ≈13% at the S-band and ≈8% at the Ka-band have been established. It reveals a gain of 53 dBi at Ka-band and 29 dBi at S-band. The antenna demonstrates improved features, and measured results are enhanced compared to the earlier reported investigations.

Design and characteristics of a multiband communication satellite antenna system

Feasibility studies on a multiband communication satellite antenna system and the key technologies involved in devising this system are described. The proposed multiband communication satellite utilizes four frequency bands: Ka (30/20 GHz), Ku (14/12 GHz), C (6/4 GHz), and S (2.6/2.5 GHz). It has six beam configurations, three multibeam and three shaped-beam. The following key technologies are presented: (1) a low-loss frequency selective subreflector (FSR) for compact feeds, (2) a low-loss and broadband frequency selective surface (FSS), and (3) a highly accurate and reliable mesh reflector. >

Low-loss Ka-band frequency selective subreflector

A frequency selective subreflector with two separate focal fed positions for a 30/20 GHz offset Gregorian reflector antenna is newly developed. For a bandwidth exceeding 3 GHz in the 20 and 30 GHz band, the measured losses are 0.7 and 1.5 dB, respectively.