Design Of Low Frequency Electric Field Probe With Multi-antenna Combination

With the rapid development of electronic equipment,the electromagnetic environment in which people live is becoming more and more complex,and the corresponding electromagnetic radiation problem is becoming more and more serious.Electromagnetic radiation not only affects people's health,but also interferes with the surrounding electronic equipment.As the core component of measuring electromagnetic radiation,the electric field probe is the key content of electromagnetic radiation detection research.In this thesis,based on reference to relevant domestic and foreign research documents,two electric field probes are designed and manufactured by the method of segmented combination,which can cover the frequency band of 1Hz?3GHz.The main work of this thesis is as follows:(1)For the frequency band of 100 k Hz?3GHz,the structure of lumped resistors loaded dipole antenna and Schottky diode combination is adopted in this thesis.The characteristics of the receiving antenna are simulated by using electromagnetic simulation software CST,and the influences of loading different R,L,C lumped elements,loading resistor size,resistor number,and resistor arrangement on the frequency response of the antenna are analyzed.In order to solve the problem of working frequency range and detection sensitivity of electric field probe,the equivalent circuit model of the antenna and Schottky diode is established by using the simulation software Tina-TI.The influence of each parameter of the diode on the detection characteristics of the electric field probe is analyzed,the selection suggestion of the diode is given,and the type of the required diode is determined.(2)For the 1Hz?100k Hz frequency band,a parallel plate capacitive sensor and circuit combination structure is adopted in this thesis.Using the low-frequency electromagnetic field simulation software ANSYS Maxwell,the influence of different structures of electric field sensors,different plate shapes and different plate sizes on the field distribution is simulated and analyzed,and the structure of the electric field probe is selected and optimized.The differential amplifier circuit and the flatness optimization circuit are designed to improve the flatness of the probe and increase the sensitivity of the probe.(3)According to the simulation results,the actual electric field probe is made,the test environment is built,and the actual performance of the electric field probe is tested.The test results show that: The test results show that the flatness deviation of the 100 k Hz?3GHz electric field probe is within ±3d B and the isotropic response deviation is within ±1d B,which can realize the electric field measurement between 1V/m?800V/m.The flatness deviation of the 1Hz?100k Hz electric field probe is within ±2.5d B and the isotropic response deviation is within ±1d B,which can realize the electric field measurement between0.05V/m?150V/m.The two electric field probes designed in this thesis have the characteristics of simple structure,easy processing and wide working temperature.In their respective working frequency bands,the flatness response of the designed electric field probes is within ±3d B.The electric field measurement of the entire low frequency band can be achieved through the combination of two electric field probes.The structure of the three measuring units orthogonal to each other ensures that the deviation of the isotropic response is within ±1d B,which can realize the measurement of the three-dimensional electric field in space.