Integrated passive intermodulation verification unit for nonlinear device

Schottky diode has been widely used in RF fields. Because of its nonlinear conductivity characteristic, it often works as a strong nonlinear device and achieves the goal of spectrum transformation, such as mixer, multiplier. Meanwhile, the intermodulation of Schottky diode can be very considerable due to its strong nonlinear conductivity characteristic. In this paper, a novel proposed passive intermodulation test unit based on micro-strip is designed to verify the intermodulation of a strong nonlinear device (Avago HSMS2820). This circuit unit integrates combiner, intermodulation detector, and works as a mini passive intermodulation (PIM) test sub-system. The reverse and forward intermodulation of the diode in this unit has been tested simultaneously and the measured 3^rd PIM level has a good agreement with the harmonic balance (HB) simulation, which proves that the unit is feasible for the verification of intermodulation distortion. In the future, this unit can be used to test other devices with different nonlinear conductivity and give a revelation for the research of the mechanism of PIM generation in frequency domain.