Omnidirectional Vest-Mounted Body-Worn Antenna System for UHF Operation

We present an omnidirectional UHF body-worn antenna specifically designed for vests worn by law enforcement agencies. Typically, body-worn antennas suffer from pattern nulling that decreases communication reliability. The proposed antenna system consists of a compact diversity module (79 × 41 × 28 mm
³
) and four antennas mounted on a typical body-worn vest to achieve an omnidirectional pattern. Each antenna element is carefully designed for body-worn mounting onto fitted vests and can operate at UHF frequencies with reasonable on-body gain. Radiation patterns are calculated and validated via measurements. Performance is also evaluated in an indoor environment for several realistic human activities. Comparison to a simple whip monopole antenna is also provided.