Calculation of Parabolic Antenna Near-Field Coupling Characteristics with PO and Measurement Verification

The large radio telescope and the surrounding electronic equipment reside in the near-field region, where the coupling response between the electromagnetic signal and the parabolic surface directly impacts the telescope's electromagnetic compatibility design. We used the physical optics method to compute and analyze the electromagnetic coupling gain response of a 3 m aperture parabolic antenna in the 1-6 GHz frequency band to address the technical challenge of calculating electromagnetic coupling between near-field signals and the parabolic antenna. Based on this, we constructed an electromagnetic coupling measurement system and compared the measured data with theoretical calculations, showing an error of approximately 5 dB, thereby verifying the accuracy of the method. This method can be used for near-field electromagnetic coupling analysis of large radio telescopes, supporting the electromagnetic compatibility design of the telescope.