Low-Profile Wideband Monopolar UHF Antennas for Integration Onto Vehicles and Helmets

A novel design of a low-profile wideband monopolar antenna is proposed with integration examples for vehicles and helmets. Initially, a monopolar antenna size is reduced by adding four symmetrical tapered slots on an edge-shorted patch. The antenna is first designed to be integrated onto a large flat ground plane that is applicable for vehicular installation. This design is later adapted for integration onto a helmet with a finite-curved ground plane, where the helmet material is included as part of the design. This study shows that a curved ground plane improves the radiation patterns at broadside and further reduces the antenna height. Both vehicle and helmet antennas have been optimized to operate in a wide frequency range from about 800-2300 MHz. These antennas radiate in a monopole-like pattern with vertical polarization and high radiation efficiency that makes them suitable for transmission applications. Good agreement between simulation and measurement is obtained, which ultimately validates the proposed design technique.