The Design Of A 440GHz Frequency Doubler

Terahertz(THz) technology has high potential of application in imaging and detection sensor system, Internet of Things, high-speed wireless communication, astronomy, security detection fields. Due to the lack of the terahertz sources and detection equipment, the development of terahertz technology mainly is restricted. Therefore, in terahertz technology fields, the source is still the most important that need to be solved. Solid-state frequency sources is mostly designed by the use of semiconductor technology, and have more advantages than other terahertz radiation sources, such as compact structure, more lighter, high reliability, low cost. These advantages make solid-state frequency sources become an important choice in the local oscillator of super heterodyne receiver, and has a major position in terahertz radiation sources. Solid-state frequency source achieve widespread attention in terahertz technology fields. Now, the output frequency of solid-state frequency sources has exceeded 2.7THz.In this thesis, the development tendency and basic theory of balanced doubler were introduced, and some relative parameters of the diodes was calculated according to the theory of Schottky varactor diodes. On this basis, after analysis of the circuit structure of doubler, the 3D electromagnetic modeling of diodes and circuit structure of passive part, by the use of HFSS and ADS, designed the input and output matching circuit, the transition from microstrip to output waveguide and the DC bias circuit, and then complement the design of 440 GHz doubler. Then, the 3-Dimentional THz balanced doubler cavity block is designed, and the quantitative machining and assembly error analysis are done by using system-level accurate THz doubler modeling. The multiplying circuit is implemented by a 50 μm quartz suspended microstrip circuit, and the DC bias circuit is designed by a 0.127 mm Rogers RT/ duroid 5880 micrstrip circuit. According to the experimental test, when the input power is 20 mW,bias voltage is-1V, the 440 GHz doubler achieved signal’s output power of 0.005mW~0.04 mW at the frequency range of 440GHz~448GHz. And output power is 0.039 mW at the frequency of 445.92 GHz. The experimental test didn’t achieve expectation. However, the research of this paper will provide the valuable practical experience for terahertz semiconductor device.