Submillimeter Multiplier

Sub-millimeter wave plays a particular role in electromagnetic wave frequency spectrum. Therefore, it has important academic value. Until now, few research achievements on sub-millimeter multiplier source are reported in China. In this work, schottky barrier diode and quartz substrate circuit are assembled in the middle of waveguide cavity, input and output ports are standard waveguide.There are two ways to obtain sub-millimeter wave signal sources, one is directly obtaining from kinds of oscillator, and the other is multiplying the millimeter frequency. The multiplying method using semiconductor devices is frequently adopted in sub-millimeter wave frequency band. The source obtained by this method is relatively small, easy to adjust, and have longer life.In this paper, the schottky barrier diode even multiple theory, FET frequency multiple theory and harmonic balance method are first analyzed. And the circuit topology is constructed based on the design theory of frequency multiplier. The devices are fixed in series on the hybride junction beteen input waveguide and suspendend microstrip, which can satisfy the require of even frequency multiplier. At first, the circuit of even frequency multiplier is designed and simulated, the optimal matching load is abtained by load pull method. An conversion from suspended microstrip to waveguide intergrated with bias circuit is proposed when designing output matching circuit in this paper. Then, the input matching circuit is designed by simulations and optimization in HFSS, where the diodes are substituted by lump port and the embeded impedence are input impedence of diodes.At last, a 180GHz balance passive 2th frequency multiplier and a 360GHz balance passive 4th frequency multiplier have been designed, and the 180GHz balance frequency multiplier has been fabricated and tested.The measurement results show that the 180GHz signal is obtained successfully with average loss of 20.8dB and a minimum loss of 16.8dB. It is the first time, as the best of we known from the published literature, that the 180GHz signal is obtained by using multiplying method with solid state circuits in our country.