Thermographic Investigation of Frequency-Reconfigurable Wearable Antennas

The thermal behavior of a frequency-reconfigurable wearable textile antenna is investigated in this paper through in-frared thermography. The relationship between the temperature of the textile antenna and the input power is experimentally considered to identify the antenna hot spots. It is found that, the highest temperature point is mainly at the tuning component location, which is consistent with the loss predictions from electromagnetic simulation tools. A clear correlation is confirmed between the radiation efficiency and temperature of the varactors used as tuning elements. It is also observed that tuning frequency remains stable despite the antenna input power variations within the range from 21 to 521 mW. The presented preliminary results demonstrate the use of infrared thermography as a valuable tool for characterization of thermal safety margins of wearable devices and for imaging of losses in reconfigurable antenna technology.