Abstract: The semiconductor layer structure of schottky varactor diode is analyzed and modeled; the field-circuit coupling method is used to study the reciprocity . the frequency response characteristics of diode structure are analyzed, Efficient frequency multiplier technique for D band varactor diode and the property of terahertz frequency multiplier are crucial . The techniques of realizing high frequency, high power, broadband, efficient and low noise terahertz frequency multiplier have been increasingly investigated. simulation of terahertz sub-harmonic frequency synthesizer system, accurately modeling and simulation of planar schottky diode, terahertz schottky diode planner technology.