A Compact and High Gain UHF Antenna for Wide Band Operations

This study introduces a compact UHF antenna designed to operate over a wide frequency span extending from 500 MHz to 3 GHz. The antenna targets broadband measurement and test applications, where stable radiation characteristics and consistent transmission behavior are of greater importance than strict impedance matching. Achieving wideband operation at lower UHF frequencies using planar microstrip-based structures is inherently challenging due to size and matching constraints. To address these limitations, a novel three-dimensional antenna configuration is developed, incorporating a microstrip-fed monopole radiator, a grounded disc, a shorting rod, and a parasitic disc element. The radiating patch is realized on a low-cost FR4 substrate, providing an economical and practical fabrication approach.Parametric simulations are conducted to optimize the antenna dimensions and to assess the contribution of individual structural components. The results demonstrate acceptable impedance performance and stable radiation behavior across the operating band, with notably enhanced realized gain observed in the 1.5–3 GHz frequency range. A fabricated prototype further corroborates the design through close agreement between simulated and measured S11 responses.