Design Of Terahertz Diode Detector

The terahertz wave is an electromagnetic wave of 0.1 Thz~10 THz.Compared with other frequency bands,the application of terahertz technology is still immature,mainly due to the lack of effective terahertz source and terahertz detection equipment.The current mainstream terahertz band detectors include mixer receivers,bolometers,superconductor receivers,and diode direct detection receivers.The bolometers and superconducting receivers need to work in a low-temperature environment.Mixer receivers have high sensitivity and good noise figure.They are mostly used in areas such as space remote sensing and deep space exploration where the sensitivity requirements are relatively high,but the circuit structure is complicated and the cost is also expensive.In contrast,the direct detection technology composed of Schottky diodes,wroking under room temperature environment,has a very short response time,and the cost is relatively cheap.In addition,it has a simple structure,low power consumption,and small volume,and does not require local oscillator.Schottky diodes are widely used diodes in the terahertz field and are often used to design components such as mixers,frequency multipliers,and detectors.Its SPICE parameter characterizes the basic characteristics of the diode and is a very important parameter in the simulation design.This paper extracts the SPICE parameters of the diode from the measured I-V data through the theoretical method and the ADS-based optimization method.The Schottky diode itself has some parasitic parameters,which is generally not considered when designing the microwave or millimeter wave circuit,but in the terahertz band,the parasitic parameters will have a greater impact on the circuit.The equivalent circuit formed by its parasitic parameters is analyzed according to the model structure of the diode,and the parasitic parameter values are extracted based on the HFSS field simulation results.In this thesis,two monolithic terahertz detectors based on microstrip line and suspended microstrip are designed.The key parts of the circuit are designed by HFSS software,including waveguide to microstrip transition,low-pass filter,and matching circuit.DC loops,etc.,and combine the field simulation results of the entire structure with diode SPICE parameters to perform overall harmonic balance simulation in ADS.The design results basically meet the requirements.The maximum detection wave voltage sensitivity of the microstrip detector is higher than 1000V/W.The reflection coefficient is better than-25 dB,the voltage sensitivity of the suspended microstrip detector is higher than 900V/W,and the corresponding reflection coefficient is better than-25 d B.At present,the layout of the detector has been completed,and is currently in the process of tapeout.The test and result analysis will go on later.