The WI-137-UAR-20 is a laboratory-grade microwave Standard Gain Horn Antenna professionally engineered by Fei Teng Wireless Technology Co., Ltd. (FT-RF) for high-fidelity directional transmission, radar benchmarking, and anechoic calibration routines across the 5.85 GHz to 8.2 GHz C-Band spectrum. Optimized to enforce exceptional boresight resolution paths, this premium horn antenna delivers an elevated nominal directive gain profile of 20 dBi combined with an exceptionally low maximum V.S.W.R threshold of 1.3 : 1. Precision CNC machined from high-grade structural aluminum alloy in Taiwan, the advanced horn flare geometry establishes a highly concentrated directional radiation footprint, providing narrow -3dB beamwidths of 20° in the H-plane and 19° in the E-plane matrix. Equipped with a standardized rectangular UAR Flange layout for direct connectivity without bulky adapters, this robust 680 g instrument ensures flawless leak-free electromechanical coupling and safely manages high continuous wave power loads up to 800 Watts (CW). This optimized structural footprint avoids destructive field distortion modes, making it the definitive choice for long-range communication links, antenna gain measurements, intensive EMI/EMC testing scenarios, and mission-critical Signal Defense reference arrays.