Saw Device Electromagnetic Compatibility Technology Research

Surface acoustic wave(SAW) device is an advanced analog signal processing device by means of acoustic wave character .Since SAW technologies is applied thirty years ago ,SAW devices accelerate growth because of their broad use and in the meantime their performance are raised constantly.Because its high performance,light weight and good consistency, it is widely used in modern microwave communication and radar system and so on. Now the development in radio communication system and sensors productively need SAW devices of high performance and high frequency. But electromagnetic interference of SAW device is evident day and day .So the SAW device technologies of the electromagnetic interference and electromagnetic compatibility in its process of design, fabrication and production must be considered .The demand request SAW designer of second order effects which are not considered in low frequency. Before now because operating frequency was low, suppose that electrode in SAW device has no thickness and thus second order effects are ignored. These second order effects, including electromagnetic feedthrough, triple transit interference, body acoustic wave, reflection and so on, affect the performance of SAW device in high frequency. So it is important that second order effects are researched and improved in depth. In this paper which gets with military and civil use. For SAW device and its correlative circuit system, the interference mechanism and interference immunity character are investigated in a good EMC light. By use of coupling-of-modes model ,this paper computers the characteristic impedance, then puts emphasis on the feedthrough effect which affects SAW performance and some advice is given. If this research work can be applied in future, it is a practical value to improve the stabilization and credibility of SAW device in complex electromagnetic circumstance.