on the lower surface thereof here comprised of copper the conductive layer on the lower surface of support structure 30 is removed entirely with a suitable chemical etchant layer 15a is etched using conventional photolithographic chemical etching techniques to provide flared notch 16a more specifically layer 15a is etched to form flared notch 16a main slot portion 22a and rearwardly extending slot portions or slotline circuit portions 64a 66a also etched into conductive layer 15a is slot 44 as shown support structure 42 similarly has copper layers 68 17a clad onto upper and lower surfaces thereof respectively like conductive layer 15a the conductive layer 17a disposed on the lower surface of support structure 42 has a flared notch 16a a main slot portion 22a and branch slot portions or slotline circuit portions 64a 66a etched therein using conventional photolithographic chemical etching techniques the conductive layer 68 clad onto the upper surface of support structure 42 is selectively etched to provide radio frequency feed 20a fig2 and 3 here providing a stripline circuit note however that feed 20a may alternatively be a coaxial or a slotline transmission line each of feed branches 36a and 38a has a transition end portion 76 78 respectively coupled thereto as will be described here the feed 20a is comprised of copper with a thickness of approximately 0 0015 inches referring briefly to fig3 it is noted that feed 20b differs from feed 20a in inter alia the length of the feed branches 36 b 38b more specifically here feed branches 36a 38a of feed 20a are longer than feed branches 36b 38b of feed 20b this length difference.