In this paper, an automatic near-field measurement system is introduced to record the electromagnetic emission (EME) of equipment under testing (EUT). Firstly, a camera is used to capture the measurement area, which is combined with an image positioning method to achieve fast and accurate positioning of the area. Then, based on the wavelet transform and autocorrelation transform of the EME signal identification algorithm, the system further identifies the broadband and narrowband characteristics of the signal and obtains the power distributions of the corresponding characteristics. In performance tests, the near-field probe moves with a minimum stepping accuracy of 0.1 mm. The movement error of the consistency and stability are guaranteed as less than 1% of the set value. The image positioning error in the 30 cm × 30 cm scanned area is less than 0.5 mm. Finally, the system identifies EME signals from a circuit with multiple crystal oscillators and a sine signal, predictive identification of the circuit functions under the metal shell of a router system. The proposed measurement system therefore offers great measurement accuracy, stability, and efficiency.

In this paper, a novel conducted susceptibility (CS) test system is proposed to analyze broadband interference for equipment under test (EUT). This system can quickly locate the susceptibility frequency bands and effectively find the susceptibility thresholds. The system can generate a unipolar or bipolar Gaussian pulse signal with a pulse width of less than 720 ps to perform these functions. In addition, the pulse amplitude can be adjusted from ±50 V to ±1.5 kV under a 50 Ω resistance load. The repetition frequency is adjustable within the range of 1 Hz to 1 kHz. The pulse spacing of the bipolar Gaussian pulse signal can be controlled from 0.25 ns to 12 ns in the step of 0.25 ns. In detail, a CS test on an electric vehicle was performed with the proposed system and an existing CS system. By using the proposed system, three potential problems of electric vehicles were predicted, susceptible frequency bands were located, and susceptibility thresholds were determined. The proposed method has high test efficiency and high reliability.

Domain decomposition methods (DDMs) can effectively solve electromagnetic scattering problems induced by multiscale perfectly electrically conducting (PEC) objects. However, boundary conditions between adjacent subdomains usually need to be carefully treated, especially when nonconformal meshes exist. To mitigate this issue, an iterative nonconformal domain decomposition surface integral equation (IDD-SIE) formulation is proposed. Each subdomain is independently solved with scattering fields generated from other subdomains as additional excitations. The continuity of current densities across touching interfaces is guaranteed by iteratively solving coupled fields among subdomains. Therefore, troublesome boundary transmission conditions can be avoided and nonconformal meshes are intrinsically supported. Numerical results show that the proposed IDD-SIE formulation is accurate and efficient, and has excellent convergent properties in terms of iteration numbers.

The radar cross section (RCS) of multiple maneuvering targets is essential for radar design. However, it is challenging to make an accurate and real-time estimation for large problems. This letter proposes a novel scheme for efficient quasi-dynamic RCS estimation for multiple targets based on offline polarization scattering matrices (PSMs) of each target. It exploits the fact that the scattering characteristics of each target remain unchanged when they are in motion, and the PSM can be treated as its transfer function. The scattering fields of multiple targets are approximated by first calculating the response of each target separately and then synthesizing them. Therefore, the multiple targets scattering problem is decomposed into small subproblems, and the transfer function of each target can be reused. An error estimate is also derived to assess the effectiveness of the results. Two numerical examples involving several missiles and airplanes demonstrate the effectiveness of the proposed scheme. Results show that the proposed scheme can significantly reduce memory consumption and enhances online computational efficiency while maintaining a high level of accuracy in the RCS estimation compared with the traditional full-wave methods.

To describe and control the polarization state of electromagnetic waves, a polarization control operator of the complex vector form is proposed. Distinct from traditional descriptors, the proposed operator employs an angle parameter to configure the polarization state of the polarized wave. By setting the parameter in the proposed operator, the amplitude of the field components can be modified, resulting in changes in the magnitude and direction of the field vector, and thus realizing control of the polarization state of the electromagnetic wave. The physical meaning, orthogonal decomposition, and discrete property of the proposed operator are demonstrated through mathematical derivation. In the simulation examples, the polarization control operator with fixed and time-varying parameters is applied to the circularly polarized wave. The propagation waveform, the trajectory projection and the waveform cross section in different reception directions of the new electromagnetic waves are observed. The simulation results indicate that complex electromagnetic waves with more flexible polarization states can be obtained with the aid of the polarization operator.

We proposed an adaptive error control approach in the method of moment (MOM) for the electromagnetic scattering analysis. In the proposed approach, an adaptive procedure is used to gradually refine meshes until convergent results are obtained. The relative coarse meshes are applied for initial numerical solutions at the beginning of the adaptive procedure. Then, meshes are refined and the normalized standard deviation (STD) between current and previous solutions is used to measure the accuracy. If the STD satisfies the pre-defined threshold, the adaptive procedure stops and convergent results are obtained. Two numerical examples including an airplane and a large ship are carried out to validate the robustness and effectiveness of the proposed approach.