A Simple Defected Ground Structure to Reduce Backside Radiation for Biomedical Applications

This paper presents a defected ground structure (DGS)-based microstrip patch antenna for applications in the Industrial, Scientific, and Medical (ISM) band. The resonant frequency of the antenna is 2.33 GHz. The −10 dB impedance bandwidth of the antenna is 20 MHz (2.32-2.34 GHz), which satisfies the bandwidth requirement for most applications in the ISM band. The front-to-back ratio improves from 12 dB to 18 dB after incorporating the proposed DGS design without varying the overall gain. In addition, the proposed design has a reduced specific absorption rate from 1.54 W /kg to 0.53 W /kg, as averaged over 1 gm of tissue. This simple and low-profile antenna with the DGS is therefore suitable for biomedical, wearable devices, on-body sensors, and microwave imaging applications.