Research on millimeter wave broad-band and low insertion loss limiters based on Butterworth low pass filter

Equivalent circuit of a millimeter wave limiter is analyzed based on Butterworth (maximally flatness) low pass filter model. Considering the parasitic components of the limiter diodes, the whole limiter physical structure is setup. Diode parasitic parameters, bonding wire inductances, and complete limiter circuit matching networks are analyzed with EM software. A Ka full-band low insertion loss limiter is realized, the measured small-signal insertion loss is lower than 4.3 dB in 26~40 GHz, the lowest insertion loss is 2.2 dB, and the VSWR is better than 1.95:1. At large signal condition with input continuous wave power of 0.5 W, the peak leakage power is lower than 10.5 dBm. The dimension of the limiter is 20×12×6 mm3, and its performance achieves the level of similar foreign products.