Xiaodong Pan

A Pulsed Differential-Mode Current Injection Method for Electromagnetic Pulse Field Susceptibility Assessment of Antenna Systems

In this paper, a pulsed differential-mode current injection (PDMCI) method is proposed for radiated susceptibility assessment of antenna systems exposed to the harsh electromagnetic pulse (EMP) environment. Two types of coupling devices used for the injection and monitor of the high-power microwave and the wideband EMP, respectively, is designed based on the directional coupler. The coupling devices are applicable from kilohertz to gigahertz, by employing which the waveform distortion of the injected narrowband and wideband pulses can be avoided. To achieve the equivalence with the wideband EMP radiation, two methods are presented to obtain the waveforms of the equivalent injected voltages, when the reflection at input port of the equipment under test (EUT) is negligible or not. By using the linear extrapolation approach, the proposed method can achieve the equivalence with the high-level EMP radiation experiment, which is difficult to perform in the laboratory currently. This extrapolation method is also effective even if the response of the antenna system is nonlinear. By employing typical antenna systems with different nonlinear EUTs, the feasibility and the accuracy of the PDMCI method are verified.

Electromagnetic Compatibility Prediction Method Under the Multifrequency in-Band Interference Environment

An electromagnetic compatibility (EMC) prediction method is proposed to overcome the insufficiency of the single frequency threshold and prediction methods of statistical analysis. Two prediction models are established based on different sensitive parameters by analysis of the interference mechanism. Effect index is defined to predict EMC. If the effect index reaches or exceeds 1, the communication equipment will be disturbed. The radiation test platform of multifrequency in-band interference is designed, with two different types of communication radios as the equipment under test (EUT). The sine and amplitude modulation (AM) wave, dual-frequency, and tri-frequency radiation tests were performed. Test results show that the sensitive parameter of equipment can be distinguished by sine and AM wave susceptibility threshold; all of the effect indexes of EUT I which is sensitive to peak-field strength exceed 1 and all of the effect indexes of EUT II which is sensitive to average power are around 1. For reducing the model error, the modified Model I is proposed and the effect indexes of EUT I are about 1.1. The method in this paper can effectively solve the problem of multifrequency in-band EMC prediction for the communication equipment and improve EMC standards.

Acceleration Technique of Modeling Lossy Reverberation Chamber Using FDTD Method Based on Quality Factor

Aiming at accelerating the simulation of the lossy reverberation chamber using the finite-difference time-domain method, a fast and accurate approach is proposed. The lumped losses of the real chamber are equivalently substituted by adding the artificial-loss atmosphere, which is evenly distributed throughout the chamber. Unlike the lumped loss, such even loss could reduce the simulation time dramatically. The conductivity of such medium is evaluated on the basis of the quality factor of the reverberation chamber, which is generally deemed as the capability of composite losses, rather than by manual attempts or experience. As examples, two different sorts of excitations are simulated to validate the correctness and generality of the artificial-loss technique.

Research on Wideband Differential-Mode Current Injection Testing Technique Based on Directional Coupling Device

This paper presents a new kind of differential-mode current injection test method. The equal response voltage on the cable or the antenna port of the equipment under test (EUT) is regarded as equivalent principle for radiation and injection test. The injection and radiation response analysis model and the injection voltage source extrapolation model in high intensity radiated field are established. The conditions of using differential-mode current injection as a substitute for radiation are confirmed. On the basis of the theoretical analysis, the function and structure design scheme of the directional coupling device is proposed. The implementation techniques for the single differential-mode current injection method (SDMCI) and the double differential-mode current injection method (DDMCI) are discussed in detail. The typical nonlinear response interconnected systems are selected as the EUT. The test results verify the validity of the SDMCI and DDMCI test methods.

Novel injection methods for substitution of irradiation under different coupling routes of electromagnetic interference

At present, the maximum electromagnetic radiated field strength which can be simulated is not able to satisfy the requirements of electromagnetic environment effects tests on electronic systems. To broaden the effective frequency range of the current injection technique, new current injection methods were put forward for substitution of the radiation. A wide-band current injection device was designed based on the symmetric directional coupler principle. With a typical antenna receiving system under test, the validity of the methods were analyzed by theory and verified by experiments when the Equipment Under Test (EUT) had different coupling routes of electromagnetic interference (EMI). The results indicate that: firstly, the relationship between radiated fields and injected voltage is linear, even if the responses of the system are non-linear; secondly, the method is valid even if the test frequency is up to gigahertz; thirdly, the novel methods of current injection are able to substitute for irradiation effectively when the antenna and the interconnected cable are the main coupling routes of EMI respectively.