High performance of resistive thin-film terminations for microstrip lines

We present a study of a broadband non-grounded termination for microstrip, intended for use in sideband separation SIS-mixers at millimeter-wavelength for APEX project. The termination consists of a specially shaped resistive thin-film placed in the strip plane without ground connection. We developed an analytical model validated by comparison to simulation data and scale model measurements at around 10 GHz. Design considerations about the termination shape, minimizing area and its effects on the termination performance are presented.