The Microwave Dielectric Detection System Research And Design

In recent years, with the fast development of microwave detection technology, a variety of microwave antennas and microwave devices have been widely used. Many scientists are paying attention to the research and development of high-performance microwave detection technology with strong interest.Microwave is a kind of high frequency electromagnetic wave, and material's absorption and reflection ability relies on its permittivity factor. When the microwave goes through aquifer material, the energy loss caused by the moisture content is remarkable. Therefore, to measure the power attenuation is a useful way to measure the material's composition.Based on the microwave nondestructive testing techniques, this thesis designs a microwave dielectric testing system. It is generally made of three parts: the launch part which contains a signal source and a sensor, the reception part is composed of sensors and microwave circuitry, the signal processing part that consists of detection circuit, amplifier circuit, the indicating circuit and the record and display unit. In this paper, The main ideas go as follows:1. A complete medium microwave detection system is designed based on the microwave nondestructive testing techniques, the characteristics of liquid mixtures and general flammable liquids, and the basic principles of microwave detection.2. The key devices such as micro-strip are analyzed and discussed in detail. A new type of circular micro-ship patch antenna is designed and HFSS simulator is used to simulate and further optimize the antenna. What's more, a sample patch is made for the system.3. According to the characteristics of microwave rectified output signals, the signal processing and display circuit are designed with the microprocessor C8051F020.4. Experiment platform is built to test the flammable liquids and water using attenuation of microwave transmission. Feasibility and applicability range of this detection system is discussed. The detection system designed with microwave technology in this paper has good reliability and strong anti-interference ability. It is less influenced by color, structure of the materials to be measured, and therefore real nondestructive test with high accuracy can be implemented this way. This paper aims at methods and techniques for microwave dielectric diction technology, which has profound theoretical significance and practical value.