348-GHz endfire slotline antennas on thin dielectric membranes

Tapered slotline endfire antennas, of the broken linearly tapered type, have been fabricated on 1.7- mu m-thin SiO/sub 2/-Si/sub 3/N/sub 4/ ( epsilon /sub r/=4.5) membranes. Antenna patterns in the E-, H-, D-, and D-cross planes have been measured at the design frequency of 348 GHz, with bismuth microbolometer detectors. The antennas have approximately 12-dB directivity, and the -10-dB beam widths are 50 degrees and 56 degrees in the E- and H-planes, respectively. The 348-GHz measurements have been compared with model measurements at 45 GHz, and show good agreement.<>