Reconfigurable Sensing Antenna With Novel HDPE-BST Material for Temperature Monitoring

A UHF-band reconfigurable sensing antenna (RSA) with temperature sensation function is presented in this letter. In order to obtain a high sensitivity, a novel composite material-namely, high-density polyethylene Ba_0.3Sr_0.7TiO₃ (HDPE-BST)-is developed to have a large temperature coefficient of relative permittivity, which varies from 7.10 at 20°C to 6.66 at 80°C. This material is directly integrated into a patch RSA design as substrate. Thus, the RSA frequency is reconfigured by the environmental temperature. To increase the temperature sensitivity, the bandwidth of RSA should be as narrow as possible. To this end, a patch RSA resonating at 900 MHz is designed, with a 3-dB gain bandwidth of only 5.4 MHz (0.6%). The experimental results show that an 8 MHz/10°C frequency increment can be obtained in the temperature range from 20°C to 80°C.