Electronic scanning of linear slot arrays using diode irises

Semiconductor diodes were employed as electronic iris control elements to scan linear slot arrays at
X
-band. An iris cluster of four varactor diodes mounted inside the waveguide around each slot provided
360\deg
of phase control for slot coupling levels up to -15 dB and a reduced range of phase control for couplings up to -8 dB. Two linear arrays were fabricated with different iris cluster configurations: 1) A ten-slot array, with vertically mounted diodes, electronically scanned sum and difference patterns up to
90\deg
; 2) a five-slot array, with horizontally mounted diodes, scanned sum patterns up to
120\deg
. Both iris configurations had an RF power handling capability of about 0.1 mW.