Development and Testing of a Waveguide–Microstrip Junction in the Millimeter Range

A waveguide–microstrip junction designed to connect a WR22 rectangular waveguide with a cross section of 3.759 × 1.889 mm2 to a microstrip line on an aluminum oxide substrate with a thickness of 0.127 mm is presented. The results of electromagnetic modeling of the structure and measurement of the S‑parameters of the mockup, which includes two “back-to-back” connected junctions, are presented. In the operating frequency range with an overlap of 1 : 1.5, the values of direct and return losses of the measured mockup do not exceed –2.7 and –10 dB, respectively. The device can be used as an integrated structural element of various functional units of radio engineering systems.