Research On A Coded Passive Wireless SAW Sensor

With the improvement of people’s lives, the car will enter the door of every household, age of automobile is coming. Car safety becomes more and more important. In the view of the car safety problem, the tire problem is the biggest, so the major gradual application of automobile manufacturers need to use the TPMS (tire pressure monitoring system) to detect the tire pressure, etc.On the bases of overall research on the current domestic and international Tire Pressure Monitoring Systems, a encoded passive wireless SAW pressure sensor was designed with the advantage of passive, wireless, small size, the error small, high resolution and automatic coding. The theoretical and measurement theory design of passive wireless SAW pressure sensor were introduced, material and structure design of the SAW resonator as well as the manufacturing and packaging method were also studied in depth The aspects of innovation are summarized below.First, building a finite element modeling of the sensor, using the model to test the stress and getting the relationship between the deformation of the substrate material and stress,it is a strong basis to design a proper position for interdigital transducer IDT and reflector on the substrate.Second, the sensor we designed is divided into two main parts:the identifier part and the pressure sensing part. The role of ID is to encode each tire, the pressure corresponding to the specific derived specific tire in order to facilitate detection. Pressure sensing gets external pressure sensor and displays the pressure.Finally, It is the first ones to use frequency-modulated continuoμs wave signal FSCW to test the sensor in our country, the test is more accurate than the single-frequency, because the frequency of defects in its single-frequency, the actual value of center frequency is different to its theoretical value and it can test phase only once, but FSCW signal is different, you can cover the center frequency of the sensor and its phase value have more than one,the calculated phase values naturally more accurate.