The WI-159-UDR-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 4.9 GHz to 7.05 GHz C-Band spectrum. Meticulously optimized to enforce exceptional boresight path stability, this premium horn antenna delivers a flat 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 uniform and symmetric radiation footprint, providing a concentrated -3dB beamwidth of 12° in both the H-plane and E-plane matrices. Equipped with a standardized rectangular square UDR Flange layout, this robust 800 g component ensures flawless leak-free electromechanical coupling and safely manages continuous wave power loads up to 3000 Watts (CW). This optimized layout avoids destructive field distortion modes, making it the definitive choice for precision antenna range calibration, direction finding, intensive EMI/EMC testing scenarios, automated spectrum surveillance, and mission-critical Signal Defense reference arrays.