Miniaturized Dual-Band Antenna for Implantable Wireless Communications

A miniaturized dual-band antenna is presented for implantable wireless communications. By introducing an offset at the feedpoint, dual-band performance of a dipole antenna is realized, operating at both Medical Implant Communications Service (MICS) 402-405 MHz and Industrial, Scientific, and Medical (ISM) 2.40-2.48 GHz bands. Parylene-C of thickness 20 μm is taken as a biocompatible insulating layer, and a rather compact size of 67.8 mm³ (10.02 mm × 10.02 mm × 0.675 mm) is obtained. In order to achieve good impedance matching at the feedpoint, an inductive loop is loaded at one of the dipole arms. The measured |S₁₁ | in skin-mimicking gel shows that a bandwidth of 47.5% and 31.6% can be achieved at the MICS and ISM bands, respectively.