Development of a Microwave Interferometer System for Corona Discharge Mapping

This paper presents the development and preliminary analysis of a microwave interferometer (ITF) system for 2D mapping of corona discharges associated with narrow bipolar events (NBEs). A parallel plate antenna, optimized to operate at 0.925 GHz, achieved a return loss of -33.52 dB, a bandwidth of 41.03 MHz, a gain of 7.74 dB, and a directivity of 7.812 dBi. These performance metrics enabled the precise capture of microwave emissions, detailed spatial and temporal mapping of corona discharge behavior. The ITF system, combined with a dual-station Magnetic Direction Finder (MDF) system, determined the bearing, elevation, height, and horizontal distance of the NBEs. The result revealed localized oscillatory corona discharges near the initiation points, with minimal propagation before dispersing. Validation using Himawari- 9 satellite imagery confirmed the presence of deep convective clouds with cloud top heights reaching 18 km, while CAPPI radar reflectivity highlighted significant rainfall intensities. This integrated approach demonstrates the potential