Hardware Design Of Radio Frequency Temperature Measurement System Based On PDC Material Wireless Passive Temperature Sensor

PDC material sensor is a new type of temperature sensor,which has the characteristics of high temperature thermal stability,corrosion resistance,oxidation resistance and creep resistance.It is a high temperature polymer precursor ceramic temperature sensitive material.Using its characteristics,it can solve the problem of high temperature.Temperature measurement in harsh environments such as corrosion and corrosion.In this study,a set of RF temperature measurement hardware system was developed using the perturbation method and the corresponding relationship between the resonant frequency and temperature of the PDC material temperature sensor.The resonant frequency of a PDC wireless passive temperature sensor will change with temperature,and there is a negative correlation between the resonant frequency and temperature.In order to verify this relationship and use it to accurately measure the temperature,a radio frequency temperature measurement hardware system is designed based on the working principle of the PDC wireless passive temperature sensor and the measurement principle of the perturbation method.The hardware system mainly includes five modules,namely a radio frequency signal generation module,a radio frequency signal transmission and conversion module,a radio frequency signal detection and acquisition module,a main controller module and an external interface display module.The RF signal generation module uses LMX2592 as a RF signal synthesizer,uses a frequency doubler to double the frequency,and after power amplification and band-pass filtering,it generates a wideband constant-frequency sweep signal of 12.6GHz ~ 13.0GHz;RF signal transmission and conversion The module is to pass a broadband constant amplitude sweep signal through a circulator and a waveguide to establish a transmission channel for the temperature sensor excitation signal and a reflected signal transmission channel;the RF signal detection and acquisition module uses a coaxial detector to The frequency signal is detected and converted into a voltage signal.The AD acquisition circuit is designed to collect the signal through an adjustable inverting amplifier circuit.The main controller module uses FPGA as the main control chip to control the sweep range and sweep of the RF signal synthesizer LMX2592.Frequency step,frequency sweep points,and processing data collected by AD;the external interface display module is to display the relationship curve between the resonance frequency and temperature collected by the system.In the hardware design,the system is integrated and miniaturized,and the main controller module and some circuits in the RF signal detection and acquisition module are designed and integrated.Finally,the overall hardware system and test platform are built.The key performance indicators of each module are tested experimentally and the results are analyzed.The experimental results show that the temperature between the resonant frequency and temperature of the PDC wireless passive temperature sensor is indeed between 25°C and 350°C.There is a negative correlation.When the temperature increases,the resonance frequency decreases,and when the temperature decreases,the opposite is true.The overall response time of this hardware system is less than 1ms,and the rate of change of resonance frequency and temperature is 308KHz/?,and the temperature measurement accuracy reaches ±1.3?.The test indicators meet the system design requirements.