Low-profile Antenna Sensor Design and Implementation for Liquid Sensing Applications at 2.45GHz and 6.4GHz

In this paper, a detailed study has been performed to assess different techniques used for liquid sensing applications. Three different planar antennas have been designed at two different frequencies. The measuring technique is based on the amount of shift in resonance frequency upon changing the liquid sample. Different samples were assessed; with a dielectric relative permittivity that ranges between 1.9 and 80.4. An inset-fed patch antenna sensor was fabricated, where measured results of immersing the sensor in different samples agreed with the simulated results.