Research And Manufacture Of Automatic Measurement System Of X-Band Slotted Line

With the advancement of technology, microwave materials used in communications and military, aerospace and other disciplines more widely, the electromagnetic properties of microwave materials directly affects the performance of electronic equipment and systems pros and cons, so complex microwave materials permittivity testing technology also need more and higher requirements. Most current testing techniques are based on vector network analyzer and the computer, Using VNA to test the network parameters of the sample, the computer fetches the corresponding data from the VNA, by using the short-circuited line method to test the complex permittivity of the sample. This measurement technology can test the complex permittivity of the sample very precisely, but the volume of the test system is large, and the cost is expensive. Therefore, to build a system, which small size, low cost and capable of the complex permittivity of the material for accurate test, has great applicability.Considering the test technical specifications, test methods of complex permittivity of microwave materials, and the CPU of the test system, finally, using the short-circuited line method to test the complex permittivity of the material, and using the TI DSP(TMS320C6747) as a minimum core processor system. Developed a set of X-band automatic slotted line system, this paper carried out the design of the prototype test system and the programing of the system’s automated testing software. This paper did some research as follows:Firstly, have studied the test method of slotted line network parameters, improved the traditional slotted line, and added the motor drive device, and the probe base is improved, so that it can realize the automatic measurement.Secondly, have analyzed the hardware structure of the test system of the short circuit method, then designed the hardware of the system. That is mainly the following two parts: first, the use of DSP-serial touch screen, consisting of a small control and display system and information processing center, realized the system with the PC’s participation, achieving miniaturization; second, development of the X-band signal source, X-band coaxial rectangular waveguide mode conversion joint, made the system of rectangular waveguide and the short circuit board etc. calibration device. And buy isolator, coaxial cable and other devices, to complete the formation of automatic detection system.Finally, have studied the DSP application, method of terminal short circuit test steps and test principle, then programed the DSP automatic test software, according to the automatic test flow, to achieve the signal source and the motor drive control, signal acquisition and calculate the test results. Analysis of the test results and error sources, to improve the system.The technical indicators of the automatic detection system are as follows:Test frequency: 8.2GHz~10.2GHzTest range: R ’= 1 ~ 10 Tan = 0.001 ~ 1...