A UHF Cavity-Backed Slot Antenna Buried in Sand

Microwave and UHF antennas for sensing and communications face challenges related to impedance mismatch and detuning. Recently, cavity-backed rectangular slot antennas have proven effective for applications involving soil, wood, and human tissue. This paper presents a design methodology aimed at improving the performance of these antennas. A resonant rectangular cavity with a matching resonant slot at 2.23 GHz has a directivity of 5.6 dB and an efficiency of 40% in air. The change in the resonant frequency when the slot is buried in dry sand demonstrates the sensitivity to this material.