Compact wideband implantable antenna for wireless capsule endoscopy application in the 2.45 GHz ISM band

Abstract

Abstract This paper presents a compact wideband implantable antenna developed for wireless capsule endoscopy (WCE) functioning in the 2.4–2.48 GHz ISM band. The antenna’s miniaturized design is achieved through the integration of E - and L - shaped slots in the circular radiator, a shorting pin and defective ground structure with an inclined T – shaped slot. The final structure has compact dimension of $$\:\pi\:\:\times\:\:{3}^{2}\:\times\:\:0.254\:m{m}^{3},$$ and the Rogers RO3010 ( $$\:{\epsilon\:}_{r}=10.2,\text{tan}\delta\:=0.0035$$ ) material serves as both substrate and superstrate. Performance was assessed in homogeneous muscle and heterogeneous human phantoms, and experimentally validated by implanting the device in minced pork. At 2.45 GHz the antenna delivered − 20.8 dBi gain, and a 44.02% impedance bandwidth. The specific absorption rate (SAR) values are recorded as 216.8 W/kg (1 – g) and 30.2 W/kg (10 – g). The study demonstrates that the antenna reliably supports wireless links beyond 10 m, maintaining a 10 dB margin at 2.45 GHz.