Broadband body-worn antenna using a top-loaded pyramidal radiator

• Published in: IET microwaves, antennas & propagation Vol. 14; no. 4; pp. 329 - 334
• Main Authors: Jackson, Brad R, Merkley, Eric
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 25.03.2020
• Subjects: antenna feeds; antenna radiation patterns; broadband antennas; broadband body‐worn antenna; emergency services; etched copper‐clad microwave laminate; flat ground plane; frequency 890.0 MHz to 13.7 GHz; helmet antenna; human body model; impedance bandwidth; impedance matching; microwave antennas; military applications; monopole antennas; omnidirectional antennas; planar antennas; pyramid‐shaped radiator; radiation patterns; Research Article; top‐loaded pyramidal radiator; wide‐bandwidth low‐profile quasiomnidirectional antenna; monopole antennas; etched copper-clad microwave laminate; microwave antennas; frequency 890.0 MHz to 13.7 GHz; broadband antennas; military applications; impedance matching; wide-bandwidth low-profile quasiomnidirectional antenna; impedance bandwidth; helmet antenna; broadband body-worn antenna; top-loaded pyramidal radiator; omnidirectional antennas; antenna radiation patterns; human body model; flat ground plane; antenna feeds; emergency services; planar antennas; radiation patterns; pyramid-shaped radiator
• ISSN: 1751-8725; 1751-8733; 1751-8733
• DOI: 10.1049/iet-map.2019.0825

A wide-bandwidth low-profile quasi-omnidirectional antenna is presented and experimentally demonstrated when integrated with a helmet for emergency services or military applications. The antenna consists of a pyramid-shaped radiator that is top-loaded with an etched copper-clad microwave laminate with two shorting strips used to improve the input impedance matching, particularly for lower frequencies. The design and operation of the antenna are first introduced using a flat ground plane, and then experimental results are reported when it is installed on a helmet where the outer surface of the helmet is used as the ground plane. The results show a very wide impedance bandwidth from 890 MHz to 13.7 GHz (VSWR $\le $≤ 3) and predominately monopole-like radiation patterns up to $\sim $∼11 GHz. The antenna has a height of $\lambda $λ/16 at the lowest operating frequency of 890 MHz (21 mm). Simulation results with a human body model demonstrate the significantly improved omnidirectionality of the proposed helmet antenna compared to more conventional body-worn antennas used in some applications.