Compact Wireless Ice Detection System with electrode used as antenna

Abstract

This paper presents a sensor system for capacitive ice detection, with planar electrodes located on a PCB. In order to minimize the required area, the electrodes are concurrently designed as an antenna structure for wireless data communication. With this approach a compact and thin sensor system for capacitance measurements can be realized. The capacitive sensor works on the principle of a mutual capacitance measurement method. An electrode of the sensor system works on one hand as an excitation source, emitting an electric field with a few hundred kHz and at the same time on the other hand the electrode acts as a 2.45GHz ISM patch antenna for wireless data communication. The scientific questions addressed in this paper are: Are the parasitics introduced as a result of the patch antenna and transmitter/receiver electrodes controllable under the assumption that the measured capacities are within the range of several hundred femtofarads? Do the capacitive couplings of the measuring electrodes influence the matching and the radiation pattern of the antenna, so that wireless data transmission is still possible? For both questions also the impact of the temperature is investigated.