Performance evaluations of UHF-RFID flexible antennas fully-integrated with epidermal sensor board

Bio-integrated wireless systems require to integrate electronic modules for bio-signal processing within a stretchable and soft skin-like device. The size and complexity of the PCB hosting circuitry cannot be separated from the design of the antenna used for the communication. Challenges arise when high frequencies are involved so that human body losses will deteriorate the radiation gain. This paper describes the design of a UHF-RFID epidermal antenna integrated with different types of EMG-sensor board arrangements in comparison with a benchmark configuration. The purpose is to evaluate the effect of the PCB metallization and identify the optimal antenna size. An overall 40 $\times 40\mathrm{m}\mathrm{m}^{2}$ device footprint is found to minimize the disturbing effects of the sensor circuit on the antenna performance and a read range up to 150 cm can be achieved.