Investigation of Choke Blinders for Feed Horns of Radar Antennas

Previous studies with some reflector type antennas have shown that wide-angle radiation and consequently radiofrequency interference (RFI) can be reduced by using choke blinders on the E-plane edges of feed horns. These choke blinders, which are arrays of choke slots or grooves, were designed such that the depth and the separation of the slots were a quarter wavelength. Subsequent efforts have been concerned with how various design parameters affect the performance of the choke blinders. Experimental studies were conducted over a wide-frequency band to observe the effects of varying the number, width, spacing, and depth of the choke slots or grooves and of varying the angle, position, and length of blinders on an X-band hoghorn. The data presented enable one to make a judicious choice of appropriate design parameters.