Immunity Test System Based On TEM Cell

With the rapid development of wireless communication technology,high-power devices such as power amplifiers occupy an increasingly important position in wireless communication transmission systems.Power amplifiers no longer have a single signal power amplification function in modern wireless transmission systems,but also have multiple functions such as control,detection and protection.Relying on many functions is the good electromagnetic compatibility performance of electronic equipment.Therefore,the electromagnetic compatibility design of high-power devices such as power amplifiers has become a crucial issue in wireless transmission systems.The evaluation of electromagnetic compatibility performance plays an important role in the design of electronic equipment.At present,in the electromagnetic compatibility performance test experiment,the commonly used immunity test site is an open field or a dark room.However,the open field is easily affected by weather,site and other factors,and is uncontrollable;the microwave dark room is also costly.In recent years,TEM cells have been widely used in the field of electromagnetic compatibility testing due to their advantages.Therefore,this paper builds a set of immunity test system based on TEM cell,which can not only effectively control the test cost,but also quickly and easily evaluate the immunity of electronic devices.First of all,this article introduces the research background of electromagnetic compatibility testing,as well as the commonly used immunity test site and the advantages and disadvantages analysis.Then choose to use the TEM cell as the test site to conduct the immunity test of the device under test.According to the actual needs,this experiment design implements an immunity test system that can be applied to the DC~3GHz frequency band.The entire system includes a power amplifier,Experimental equipment such as directional coupler,power meter,handheld vector network analyzer,etc.In order to ensure the practicability and stability of the test system and meet the uniformity of the test environment,field distribution analysis and S-parameter simulation experiments were carried out on the TEM cell.Then,the TEM cell was developed from the aspects of mechanical design and process manufacturing.Finally,the implemented test system is used to carry out the immunity test of active devices and passive devices,the relevant test steps and precautions are given,and the test results are analyzed.Compared with other test systems,the immunity test system designed in this paper has the following advantages: First,considering the different test frequencies of the EUT and the different sizes of the EUT in practical applications,this paper has designed two TEM cell,one frequency band is DC~1GHz,the other frequency band is 1~3GHz,the standing wave coefficient is less than or equal to 1.4,and the field uniformity is within ?3dB.In addition,in the development of the TEM cell,the shielding door mainly adopts an embedded structure,which improves the performance of the TEM cell.Second,the test frequency band of the TEM cell-based immunity test system built in this paper is relatively wide.The entire system is easy to build and disassemble,and the cost is controllable.The required test site covers a small area and is not affected by environmental factors.Third,this article mainly uses low-noise power amplifiers and other instruments to replace complex RF systems,making the whole experiment process simple,fast,and easy to operate.