Design Of Wide Pulse High Power Microwave Switch

In recent years,as the developments in the third generation of semiconductor technology represented by GaN technology,the output power of microwave solid state power amplifier is increasing continually while its working frequency is rising.Then it becomes an important job which microwave engineers have to be faced,that improve the power handling of high power microwave switch and expand its working frequency band.PIN switch is the most commonly used high power switch at present,as it has the advantage of that a low DC power can be used to control a high RF power while its working life is not limited by the number of switches,and its switching speed is fast.The operating principle of PIN diode has been discussed and its simplified model has been given in this article firstly.Then series and parallel circuit models of the PIN switch have been analyzed,its insertion loss and isolation calculation formulas were also given.The advantages and disadvantages of different switch topology were compared.Finally,started from the aspects of PIN diode breakdown model and its thermal damage mechanism,kinds of factors that affect the power capacity of the switch have also been discussed,then the design guidelines of high power switch were given at last.The examples have been given in the instance part,such as 2 KW switch in VHF band(pulse width 1ms,duty cycle of 10%),500 W switch in L band(pulse width 4.5ms,duty cycle of 30%)and 100 W switch in X band(pulse width 1ms,duty cycle of 30%).Their design process,development results and the situations of the power experiments were also given.The design problem of microwave high power switch can be solved through the research of this subject.It also has important reference value for high power phase shifter,high power digital attenuator and other control devices at the same time.The theory and products of this work can be widely used in radar and communication systems.