The WI-187-A1-10 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 and calibration routines across the 3.95 GHz to 5.85 GHz C-Band spectrum. Meticulously optimized to enforce highly consistent reference tracing paths, this premium horn antenna delivers a flat nominal directive gain profile of 10 dBi combined with excellent impedance matching properties. Precision CNC machined from high-durability structural alloys in Taiwan, the advanced horn flare geometry establishes a highly stable radiation footprint, providing uniform -3dB beamwidths of 42° in the horizontal plane and 40° in the vertical plane matrix. Utilizing the standardized rectangular EIA WR187 waveguide architecture, this lightweight 0.3 kg component ensures flawless electromechanical alignment, eliminates boundary signal leakage, and maintains unwavering performance under continuous duty cycles. This optimized structural framework avoids destructive field distortion modes, making it the definitive choice for rigorous EMI/EMC profiling, antenna gain calibrations, anechoic range testing, and high-precision Signal Integrity verification setups inside professional RF systems.