Research On 220 GHz Frequency Multiplication Technology Based On Schottky Barrier Diodes

THz local oscillator is the core component to achieve THz systems. The method currently used to generate terahertz sources include optical methods, THz quantum cascade laser(THz QCL), solid-state electronic devices, etc. In recent years, much attention has been paid to solid state electronic devices multiplier terahertz source, it has many advantages, such as high reliability, high spectral quality, compact structure and low power consumption, has achieved rapid development.The Schottky barrier varactor chips from Teratech Components Ltd were employed in this thesis, the full three-dimensional model of Schottky diode was established, a 220 GHz tripler and a 220 GHz balanced doubler were designed.The 220 GHz tripler was designed using a unbalanced structure, so the filter circuit was designed for the free frequency recycling. In this paper, the diode simulation model combined with the three-dimensional electromagnetic Schottky diode structure and diode SPICE parameter model was established, internal port was used at the anode contact area in HFSS three-dimensional Schottky diode electromagnetic model, the diode passive structure was taken into account in the multiplier circuit design, the SPICE parameter diode model in ADS was used to represent the nonlinear characteristics of diode. HFSS and ADS were used interchangeably to design the entire circuit. In the end, the entire tripler performance was simulated in ADS with harmonic balance method.In order to reduce the conversion loss, a 220 GHz frequency doubler was designed. The doubler was designed with a balanced structure, it needed no additional filter for recycling idle frequency, the circuit structure was relatively simple. The design process was basically the same with the unbalanced tripler, except that the internal ports were lumped port in doubler design for input and output match.Finally, the above frequency multipliers were fabricated, assembled and tested. The test results showed that 220 GHz unbalanced tripler had a maximum output power of 6.34 mW, the lowest frequency conversion loss was 13 dB, typical conversion loss was 15 dB in the band 210~240GHz, got the terahertz signal of 210~240GHz successfully. When the driving power was 30~40mW, the balanced structure frequency doubler had a maximum output power of 1.71 mW, the lowest frequency conversion loss was 13.5dB and the typical value was 18 dB. If more powerful source was used, higher output power could be obtained.The designed frequency multipliers in this paper can be used as small power terahertz source. The methodology and idea in this article were universal, could provide inspiration and reference to the subsequent design at the same time.