The Research Of 220GHz Multiplier Chain

Terahertz technology has much room for development and promising prospects of applications in information science,space science,medicine,materials science and many other fields of science.Especially,the long-wave band(100GHz-300GHz)has most high practical value in Radar,wireless communication and security check systems.As of late,the development of terahertz applications is mainly held back by the terahertz waves generation techniques.Among such techniques,the most eye-catching and promising one,because of its high stability,high intergration and low cost,is the semiconductor-based multiplier source developed from lower-frequency to terahertz.The atmospheric window,in which signals can be propagated without loss,is 220 GHz.And many domestic research institutes have committed themselves to research and development of Radar and communication systems operating in this band.In such systems,solid-state multiplier source is one of the most important parts in the transceiver.Based on Schottky diode,in this thesis several frequency multiplier links are devised as RF sources for 220 GHz T/R systems or as LO sources for 440 GHz T/R systems.A 220 GHz frequency doubler is devised based on GaAs Schottky diode.Firstly a three-dimensional electromagnetic model for the diode chip is built to extract its characteristic parameters.Then the passive modules of the doubler are designed one by one and the overall circuit is optimized using harmonic balance method.At last the doubler is measured.Simulation results show that the efficiency peaks 41% with a 150 mW driven power and over 15% in the range from 210 GHz to 230 GHz.Test results show that with a driving power of 30 mW,the conversion efficiency is above 10% in the frequency range from 197 GHz to 230 GHz.The output power peaks 7.13 mW at 218 GHz with a conversion efficiency of 24%.If a higher driven power is provide,the doubler will have a better performance.A 110 GHz frequency tripler is devised based on GaN Schottky diode.Firstly the characteristics of the GaN material and the feasibility of GaN diodes are analyzed.Then a GaN planar Schottky diode chip is designed according to the GaAs diode.Lastly a three-dimensional electromagnetic model using field-circuit coupling mechanism is built to develop the tripler.Simulation results shows that the tripler perform best by a 1.5W driven power,the highest efficiency is 8% at 110 GHz.Test results show that the maximum output power is 2.7mW with a driving power of 200 mW,indicating that the efficiency of the multiplier increases as the driving power increases.The 220 GHz doubler devised in this thesis is domestically at a leading position and the co-developed GaN planar Schottky diode,providing precious experience for high power tearhertz multipler design,is a pioneering work of the field.