Compact broadband MMIC Schottky frequency tripler for 75–140 GHz

In this paper a monolithically integrated frequency tripler based on an antiparallel pair of Schottky diodes is presented. The tripler is designed for flat output power response and wide frequency range. With 2 mW of input power the tripler covers the frequency range of 75-140 GHz (bandwidth 60 %) delivering output power between -19.4 dBm and -14.7 dBm with an average efficiency of 1.1 %. The efficiency of the tripler stays almost constant in a wide input power range. With the largest available input power level of the test setup, 17.1 dBm, the tripler output power is -2.4 dBm and efficiency 1.1 % at 75 GHz, and the output is not yet saturated. The input and output matching and filtering circuits are optimized to minimize the chip dimensions. The total chip area including RF and bias probe pads is only 0.47 mm². The state-of-the-art results are achieved in the small size of the chip as well as in the wide frequency bandwidth.