Design and Experimental Evaluation of a Compact Half-Shaped Printed-Monopole Antenna with Short Stub for UWB Systems
Nobuyasu Takemura
A compact, half-shaped, planar-monopole antenna optimized for ultra-wideband (UWB) communication systems was proposed, numerically analyzed, and experimentally validated. The proposed antenna is configured as a bell-shaped monopole structure fabricated on an FR-4 dielectric substrate, which is bisected along its axis of symmetry to achieve a reduced footprint. To ensure broadband impedance matching, a short-circuited stub is integrated between the monopole and the ground conductor through a plated via. The antenna dimensions are 30 × 12 × 1.6 mm3, which represent a significant reduction compared with those of conventional UWB monopole antennas. Full-wave electromagnetic simulations demonstrate that the antenna covers the FCC-authorized UWB band of 3.1-10.6 GHz with a voltage standing-wave ratio (VSWR) of ≤ 2. Experimental measurements of properties of a fabricated prototype of the proposed antenna agree well with the simulation results. In addition to the analysis of frequency-domain performance, time-domain analysis is conducted using two identical antennas in both face-to-face and side-by-side arrangements. According to the results of the time-domain analysis, the calculated correlation coefficient between signals received by the proposed antenna is 0.986, which confirms high waveform fidelity. Group-delay analysis of the proposed antenna verified stable temporal characteristics with an average delay of approximately 0.2 ns across the UWB range. These results demonstrate that the proposed antenna is a promising candidate for compact and high-performance integration in short-range, high-speed, wireless-communication devices.
