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94.5 GHz Reflector SystemMAAS has designed, built and tested a high performance reflector system for operation at 94.5 GHz. The bandwidth is 1.6 GHz The reflector requirement is for an elliptical beam with a 3:1 ratio and sidelobes of better than -25 db in both Azimuth and Elevation. In order to achieve this, a shaped Gregorian reflector was used (Figure 1) and the required radiation patterns were obtained (Figure 2). Photographs of the horns and the Orthomode Mode Transducer as well as their RF performance are shown in Figure 3. The manufacture was carried out by Thomas Keating Limited and the measurements were carried out using the Compact Antenna Test Range at Queen Mary, London. Software from our sister company, Antenna Software Limited, was used including REFLECT for the dual reflector system and mode-matching programs, AXIAL and RTCC plus its optimiser for the waveguide components. FIGURE 1 Photograph of shaped Gregorian reflector with feedhorn and polariser present
FIGURE 2 Radiation patterns of Shaped Gregorian Reflector at 94.5 GHz
FIGURE 3 Waveguide Components at 94.5 GHz
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