Optimization of Low-Profile Antennas for

Applications in Unattended Ground Sensor Networks

D. Liao and K. Sarabandi

A comprehensive investigation into the design of optimal low-profile, electrically-small antennas for unattended ground sensor (UGS) networks operating at VHF or higher frequencies is featured in this study. Because UGS transceivers are intended for operation near the ground, ground proximity effects become extremely important for considerations related to antenna efficiency, input matching, radiation pattern, and the overall path loss between the transmitter and receiver nodes. In seeking an optimal design, the performances of different transceiver systems utilizing different types of antenna structures including the dipole, loop, ordinary circular slot, and cavity-backed circular slot are analyzed using a full-wave hybrid approach consisting of the moment method in conjunction with an asymptotic field propagation model.

Mesh model of a miniaturized cavity-backed circular slot (CBCS) antenna.	Normalized azimuthal radiation patterns of different low-profile antennas located directly above a realistic ground. It is shown that the performance of a CBCS with 0.01l thickness is the same as a short vertical dipole of length 0.1l.