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High field intensity electromagnetic radiation effect test is difficult to simulate in large-scale space, and the existing bulk current injection (BCI) technology has a limited application of the nonlinear system test. Starting from the coupling mechanism of shielded wire, an analysis model about the response of the equipment under test (EUT) is built-in radiation and injection conditions. In addition, the equivalent corresponding relationship originates between the injected excitation source voltage and the radiation field intensity. The basis for obtaining the source of the injection excitation and performing extrapolation tests is found, and the test method of BCI replacing high field intensity electromagnetic radiation is developed. Subsequently, the passing-through load and communication station tests are performed to verify the theoretical derivation and the test method. As indicated from the research results, the BCI is capable of accurately replacing the high field electromagnetic radiation effect test of the EUT, and the maximum test error reaches 2.7 dB, capable of satisfying the actual needs of the project.

The calculation of electric field in space excited by thunderclouds is an important basis for lightning warning and protection. In numerical calculation of the electromagnetic field, it is often necessary to perform multiple loop nesting calculations on several triple integrals, which consume a lot of computing resources. In order to shorten the calculation time and improve the calculation efficiency, the electric field excited by the charged thunderclouds in space is theoretically derived with the analytical method by the thundercloud cylindrical charge pile model and based on the electrostatic field theory. The complex integrand function is approximated, so that the analytic expression of electric field in space is obtained in this paper. Through simulation and comparison, it is found that the approximate solution and the exact solution are similar in size, the change trend is the same, and the approximate analytical expression can be used for the approximate calculation of the electric field in a short range. Under certain conditions, the approximate solution can be converted into an accurate solution, which can be used for the accurate calculation of the electric field. Approximate calculation not only simplifies theoretical derivation but also improves calculation efficiency. The calculation time has been shortened from tens of hours to less than one second by using different calculation methods, which is a difference of 7 orders of magnitude. With approximate analytical expression, the electric field excited by charge pile with typical structures in thunderclouds in space is calculated and the characteristics of that are analyzed in this paper. For lightning protection of mobile targets, approximate calculation is of great significance in shortening the lightning warning time and enhancing the protection effect.

In order to meet the actual demand of cloud lightning channel current inversion, a theoretical calculation model of lightning electromagnetic fields produced by vertical cloud lightning channel is established based on the dipole method, and the simplified relationship between the cloud lightning electromagnetic field at ground level from the vertical channel and the channel current is presented. By comparing the cloud lightning electromagnetic fields from the simplified expressions with that from the exact expressions, the influences of the observation distance, the channel length and the channel starting height on the accuracy of the simplified expressions are obtained, and the application ranges of the simplified expressions are also given.

The penetrative conductor is the most important coupling channel of bring the outside electromagnetic radiated field into the metal shielded box. In order to disclose the electromagnetic radiation coupling law of the penetrative conductor and the generation mechanism of the local electromagnetic field enhancement effect in shielded box caused by the penetrative conductor coupling, the induced current distribution law of the penetrative conductor under the condition of sine continuous wave radiation is studied in this paper. The penetrative conductor induced current distribution computation model is established under the condition of plane wave radiation. The analytic expression of the induced current distribution is derived. The penetrative conductor induced current amplitude distribution curve is plotted by using Matlab software at typical frequency point. The penetrative conductor induced current distribution law versus radiated frequency and conductor location is disclosed under the condition of plane wave radiation. The penetrative conductor induced current test platform based on vector network analyzer is developed by adopting current probe and optical fiber signal transmission system. The normalized induced current distribution curve at typical frequency point is measured. The test results verify the correctness of the penetrative conductor induced current distribution law and other theoretical analysis results.

In this paper, the test method using the directional coupling device as the injection device is employed to measure the radiated susceptibility of the antenna system. The susceptibility of the radio frequency front-end whose internal circuits are typically integrated circuits are measured. The differential-mode injection method can achieve the equivalence with both the continuous wave case and the electromagnetic pulse case.

A set of approximation expressions relating the lightning channel-base current and the lightning electric and magnetic fields on earth surface are proposed respectively in the near-zone and far-zone, by employing the transmission line (TL) model. The derived expressions show that, the electric and magnetic fields waveforms can be expressed approximately by the channel-base current waveform with different factors at a certain distances, whether in the near-zone or far-zone. The factors can be expressed in terms of the return stroke wavefront speed v, the speed of light c, and the horizontal distance r between the return-stroke channel and the observation point.

The formulas of tortuous channel lightning electromagnetic field are obtained by decomposing the current micro-source dipole and solving Maxwell's equations. The waveforms of lightning electric and magnetic fields in different areas are calculated using the transmission line model and pulse function. Then, the characteristics of lightning electromagnetic field for different channel geometries and the impact of lower section discharge channel length on electromagnetic field initial peak value are analyzed by comparing the waveforms of lightning electromagnetic fields. The results show that, the difference between the electromagnetic field waveforms of two models will decrease with the increasing of the distance and the upper section of discharge channel has little impact on electromagnetic fields in near area but the electromagnetic fields will be influenced by the upper section of discharge channel in intermediate and far field regions. Moreover, the peak value of tortuous channel lightning electromagnetic field in different field regions is mainly determined by the lower section length of the discharge channel.

A kind of electric and magnetic field generators with adjustable waveforms and intensity output to simulate lightning electromagnetic fields are presented. The electric fields measured by a dipole antenna and ranged from 0 to 300kV/m can be generated within the GTEM cell by feed-in of an impulse voltage. The magnetic fields measured by a ‘B-dot’ coil and ranged from 0 to 3000 A/m can be generated within the coil by feed-in of a surge from the lightning surge generator. The relatively homogeneous lightning electromagnetic pulse (LEMP) environment could be provided within certain area in the GTEM cell and the coil, which can be used to evaluate the immunity of small electronic systems or devices towards LEMP with low cost.