Compact Dual Band Feed System for a Multifrequency Atmospheric Radar

The design, simulations and measurement results of a dual frequency feed horn operating at 35.75 GHz (Ka-band) and 94.05 GHz (W-band) are presented. The horn is designed to be used as a feed for a multifrequency atmospheric radar. The design is composed of three parts, a spline profile horn, a waveguide diplexer with Ka- and W-band ports orthogonal to each other and a Ka-band waveguide iris filter. The filter is used to achieve greater than 70 dB isolation between the Ka- and W-band ports. Directivities of 21 dB and 26 dB are achieved at Ka and W-band, respectively and a −12 dB beam width of 31 and 21 degrees has been achieved at Ka- and W-band. Measured patterns at both operating frequencies along with S-parameter measurements of the filter and the feed horn assembly are in good agreement with the simulation results.