This paper presents a model to predict the shielding effectiveness (SE) and resonant modes of cylindrical enclosure with apertures or dielectric substrate. In this model, the Robinson equivalent circuit model (RECM) is introduced to deal with aperture impedance, and the extended form of the Baum–Liu–Tesche equation is deduced to calculate the induced voltage in the enclosure. The electromagnetic topology (EMT) model is established to analyze the process of energy transmission inside the enclosure. The energy propagation coefficient matrix and the scattering coefficient matrix are calculated to deal with the SE results of the observation point. To quantify the efficiency of the proposed model, the calculation results are compared with the full-wave transmission line matrix method (TLM) and RECM through the Fréchet distance. The comparison results show that the accuracy of the proposed model is better over a wide frequency range compared with RECM, and meanwhile, it consumes less run time and fewer CPU resources than traditional numerical methods. The validity of the presented model is verified by TLM.
This paper presents a precise circuit model for predicting the shielding effectiveness (SE) and resonances of the cylindrical enclosure. In this model, the waveguide theory is combined with the Robinson model to deal with the influence of the high-order modes and the arbitrary position. The transmission line theory is applied to calculate the enclosure equipped with symmetric apertures or a dielectric layer. The results show that the proposed model can accurately calculate the orthogonal components of voltage response and predict the shielding effectiveness of the monitor point over a wide frequency range. Compared with traditional numerical methods, the proposed model costs less computing time and resources to operate because of employing analytical formulations. The effectiveness of this model is verified by the three-dimensional full-wave transmission line method (TLM).
An ultra-wideband electromagnetic pulse (UWB EMP) can be coupled to an FMCW system through metal wires, causing electronic equipment disturbance or damage. In this paper, a hybrid model is proposed to carry out the interference analysis of UWB EMP coupling responses on the wires to the FMCW radar. First, a field simulation model of the radar is constructed and the wire coupling responses are calculated. Then, the responses are injected into an FMCW circuit model via data format modification. Finally, we use the FFT transform to identify the spectral peak of the intermediate frequency (IF) output signal, which corresponds to the radar’s detection range. The simulation results show that the type of metal wire has the greatest influence on the amplitude of coupling responses. The spectral peak of the IF output changes to the wrong frequency with the increase of injection power. Applying interference at the end of the circuit can more effectively interfere with the detection of the radar. The investigation provides a theoretical basis for the electromagnetic protection design of the radar.
The millimeter wave detector has been widely applied in short-range detection systems. However, it can be easily disturbed by the ultra-wideband electromagnetic pulse (UWB EMP). In this paper, we proposed a simplified model to investigate the coupling laws of UWB EMP to the millimeter wave detector. With the help of finite integration technology (FIT), the coupling process can be visualized, and the most sensitive pose and the coupling path are analyzed. The irradiation tests are carried out to verify the simulation results. The results show that the shielding effectiveness (SE) of the detector in the vertical state is the worst, and the UWB EMP enters the detector mainly through the circular opening. Under the irradiation of UWB EMP, the detector shows three phenomena: interruptions, constant false alarms, and damage. The interruptions can be recovered by power reset, while the constant false alarms and damage are irreversible effects. The results can be employed to reinforce the electromagnetic compatibility (EMC) of the millimeter wave detector. With the increasing use of short-range detection systems, the EMC of existing products must be improved.
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