Aperture matching of a dielectric loaded circular waveguide element array

An X-band phased array with dielectric-loaded circular waveguide elements was investigated. The aperture was designed to provide balanced scan characteristics for both the E- and H-planes. The results of an experimental study are presented in which the active impedance of the radiating element was matched by introducing a circumferential groove onto the dielectric plug. Both the aperture junction and the matching groove were measured to derive their respective equivalent circuits for 'look-in' and 'look-out' impedance transformations. The groove size and its location from the aperture were then optimized by a hybrid approach wherein the measured data and computer simulations were used to greatly reduce the shop time, lab tests, and the number of trials in the hardware development.<
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