Microwave Disturbance Of High Speed Digital Circuit And Electromagnetic Protection

Design of high-speed digital circuit system, facilitated by development of modern electronic technology, has become the mainstream of current electronic design. However, the system of great speed and high density has been increasingly affected by complicated electromagnetic environment. The system and equipment under it are interfered or intercepted, and some vulnerable parts are even destroyed completely. In order to avoid the said problem, a thorough study of the effect of microwave interference on the high speed digital circuit system in terms of its formation, mechanism and respective electromagnetic protective measures is highly needed. The study needs to start with the microwave interference research on the circuit units given the complexity of the circuit system.This paper, taking CMOS inverter as the object of study, constructs equivalent source model of electromagnetic interference under HPM radiation based on electromagnetic field coupling theory. It uses impedance-matching circuit directly injected with interfering microwave signal to simulate the effects on CMOS inverter of microwaves of different frequencies and power rating. In this way, it contributes to the study on complicated COMS circuits by concluding the patterns of their effects. Besides, the present study brings to light the affecting mechanism of interfering microwave signal on CMOS inverter by computing load-influenced main dynamic parameters such as output voltage, output current and power consumption. Moreover, the present study further evaluates the shielding effects of two types of typical electromagnetic material by establishing a dedicated testing system, which operates easily and can contribute to microwave shielding research.The present study analyzes the interference of microwave signal on digital circuit by simulating the effect on CMOS inverter and by computing load-influenced dynamic parameters, reflects the interference mechanism, which can be applied in analysis of the microwave interference on other circuit units. All the endeavors will contribute to future research concerning microwave interference on complex high speed digital circuit system.