A tunable water antenna

Abstract

This paper presents a pure water antenna with frequency reconfigurability, which is composed of a water resonator, L‐shaped feeder, and metal ground pad. An L‐shaped feeding structure is designed so that the working frequency can be adjusted by changing the water level of the resonator. The cross‐stack periodic water radiator structure improves the radiation efficiency by 2–4 dB compared with simple rectangular structure. The working frequency of this antenna is around 1 GHz, and will decrease by 17 MHz for every 5 mm increase in water level, which proves the feasibility of this antenna for water level monitoring. It has the potential for application in the field of wireless environmental monitoring for the Internet of Things.