In Situ Measurement Method For Eletromagnetic Radiated Disturbance Based On Array Antennas

The in-situ measurement of radiated disturbances for physically large equipment suffers from a variety of ambient signals.In order to solve the suppression of ambient signals in in-situ measurement of radiated disturbances,it is urgent to conduct the research on the suppression of in-situ ambient signals.In this paper,first,the in-situ measurement methods of radiated disturbances under the condition that the ambient signals are not classified are studied.By deeply analyzing the existing ambient signals suppression techniques based on array signal processing,the in-situ measurement method for radiated disturbances based on multiple signal classification positioning and interference-plus-noise covariance matrix reconstruction beamforming and the in-situ measurement method for radiated disturbances based on spatial domain matrix filtering are proposed.These two proposed methods make up for the deficiencies of the previous methods and achieve the suppression of ambient signals in the in-situ mearsurement to some extent.Then,the in-situ measurement methods of radiated disturbance under the condition that the ambient signals are classified are studied.Based on the classification of ambientl signals,the in-situ measurement method for radiated disturbances based on beamforming and adaptive noise cancellation and the in-situ measurement method for radiated disturbances based on signal localization,beamforming and adaptive noise cancellation and its improved method are proposed for different application scenarios.And the improved method is extended to the near-field conditions.Based on the in-depth study of the identification method and suppression method of the in-situ ambient signals,the problem of identification and suppression of multi-source ambient signals with unknown number,azimuth and amplitude is solved under the condition of fewer array elements.The proposed methods can achieve more than 50 dB suppression for the multi-source ambient signals under far-field and near-field conditions,respectively,and effectively extract the radiated disturbances of the system under test.The error between the recovered radiated signals and their true value is less than 3 dB.Finally,the 30 MHz ~ 1 GHz measurement antennas are designed and fabricated.The measurement system is built to verify the proposed in-situ measurement methods.The measurement results show that the proposed methods are feasible and provide effective ways for in-situ measurement of large equipment radiated disturbances.