Research On Terahertz All-Solid Receiver Front-End

Terahertz Electromagnetic Wave, as the only frequency resource which hasn’t been developed completely,is usually defined as the frequency varies from 0.1THz to 10 THz. Its wavelength is between millimeter waves and infrared light, so it has some advantages of millimeter waves and infrared light. It has a wide application prospect in wideband communication, Precision guidance, Environmental monitoring, medical diagnosis and so on. Master of terahertz technology is a meaningful thing for national defense and civil use. Terahertz receiver front-end is widely used in Terahertz system, such as Terahertz communication system, Terahertz imaging system.Hereby, Superheterodyne Receiver theory to design 330 GHz Terahertz receiver front-end, which consists of Terahertz mixer, filter, local oscillator, antenna and low noise amplifier. Main works are introduced as following.(1)The design of local oscillator: The millimeter wave mmic chips are used to design local oscillators for 330 GHz quadruple subharmonic mixer. The main works include:Input and output matching design, waveguide-to-probe transition design, cavity design, feed circuit design and measurement. The chips are assembled in independent cavity, and the test results show that the conversion loss of 8x multiplier is about 7.8dB, the gain of amplifier is about 16 dB and the work frequency of local oscillator is between 78 GHz to 84 GHz. The maximum output power is about 37 mW.(2)The design of Terahertz filter: The filter is used to stop noise interference. The Prototype method is used to design the filter, which works from 332GHz~358GHz, Center frequency is 345 GHz, insertion loss is about 0.2dB.(3)The measurement of Terahertz receiver front-end: The all solid Terahertz receiver front-end works at 330 GHz, RF signal is generated by 330 GHz quadruple subharmonic mixer. The receiver front-end consists of filter, mixer, IF amplifier. Based on the receiver front-end, build transceiver font-end, transmitter is as same as receiver, IF signal is 0~10GHz, input power is-5dBm, and the transmission distance is about 1.5m.(4)optimizing 220 GHz transceiver and debugging communication system: The LO of the system is 104 GHz, which include 13 GHz frequency synthesizer, 13 GHz amplifier,doubler and quadrupler,and 10.8GHz automatic gain controller(AGC) that is used at receiver. The main debugging parameters are output power, phase noise, clutter suppression. The communication system achieves transmission rate about 3.5Gbit/s, its transmission distance is about 3m.