Electromagnetic Protection Technology Of Ultrashort Wave Communication System Rf Front-end Research

High-power microwave(HPM)has brought forward a severe challenge to a variety of electronic equipment, especially to the communication system. Enhancing the electromagnetic protection capacity of communication system has become an urgent task. RF Front-End circuits is an important part of ultra-short wave communication system, when high-power microwave tests, the RF front-end circuits has been showing a clear device damage, resulting in the entire communication system can not work. Basing on the research on electromagnetic protection technology of ultra-short wave RF front-end, it will be very useful for ultra-short wave communication system to improve the overall capacity of electromagnetic protection。The first two chapters of this thesis briefly introduces research background of this thesis, the principle and protection methods of HPM, as well as the main theory of modern filter design.Chapter III of this thesis is the focus of the thesis. It brings forward three types of electromagnetic protection technology programs of high-power microwave RF front-end, and it also is carried out by theoretical simulation, the normal testing and transient electromagnetic pulse testing. According to comparing overall testing performance of the three types of electromagnetic protection technology program, from the point of view on RF front-end communication systems from lightning protection and anti-transient electromagnetic pulse, at last it makes sure that the fifth-order Tchebycheff band-pass filter and electromagnetic protection technology combined by lightning transient protection device is optimal.Chapter IV designs a DC power supply electromagnetic protection filter, through theoretical analysis and insertion loss testing, its performance achieves the design requirements. The communications system has been separately test to three transient electromagnetic pulses: unshielded power cord, power cord shielding and the electromagnetic protection-type DC power supply filter. Test results show that the power filter enhances the overall electromagnetic protection performance of communication system. Chapter V designs remote monitoring system of communication system during electromagnetic pulse environment. The principle is: By the photoelectric conversion module, the voice signals from communication system and display panel signal modulation into optical signals, through optical fiber transmission then send to a remote photoelectric conversion module, and demodulates voice signals and display signals in order to monitor the changes of communications system between voice and display panel signal. The monitoring system has been applied in the electromagnetic pulse environment, and has achieved better test results.It is concluded from the results of this thesis that, increasing patches and adding round corners are feasible methods.