Review Paper on Frequency Multiplier at Terahertz Range

Frequency multiplier is an electronic circuit which generates the output frequency which is an integer multiple of the applied frequency. For this purpose, nonlinear devices such as BJT, FET, schottky diode, varactor diode, step recovery diode are used. The nonlinear region of their characteristics is utilized to design frequency multiplier. In terahertz range stability and broad bandwidth are required factors to design heterodyne receiver. For this purpose, only schottky diode is the best option because its cutoff frequency is so high and due to this reason switching frequency of this diode is high compared to its other comparable. The design of frequency multiplier consists of three parts namely the diode structure, input and output matching circuit. The detailed discussion about sources available at terahertz frequency range, different design methods of frequency multiplier with active and passive devices, comparison of available passive frequency multiplier are presented in this paper