Compact center-fed ridged waveguide slot array for SAR applications

A new, simple, probe-fed technique for a ridged waveguide slot array is presented. The application is for satellite synthetic aperture radar (SAR). The array is fed in the center by a coaxial probe whose inner conductor is attached to the ceiling of the ridged waveguide. An example design of a 6-element slot array with the probe is evaluated by simulation. The -10 dB return loss is around 4% and the cross polarization is well below -33 dB. The feed structure offers good mechanical stability and low voltage around the feed to prevent electrical breakdown, which are critical factors for a rocket launch and for the space environment respectively.