Design and Performance Measurement of Implantable Differential Integrated Antenna for Wireless Biomedical Instrumentation Applications

The growing demand of implantable medical devices (IMDs) is crucial for enabling real-time monitoring in biomedical and healthcare fields. This article presents a differential integrated antenna for biomedical instrumentation applications in the industrial, scientific, and medical (ISM) frequency bands (915 MHz and 2.45 GHz). The size of the proposed cubic flat differential system is (0.103 lambda(g) x 0.103 lambda(g) x 0.005 lambda(g)), where lambda(g) is the guided wavelength at 915 MHz. The performance analysis of the differential antenna is carried out within homogeneous, heterogeneous, and realistic body models to design the proposed implantable integrated antenna. To validate the design method, a differential antenna is fabricated and assembled with different circuit components as per the simulation scenario and experimentally verified in the vicinity of skin mimicking phantom and minced pork. The measured -10-dB impedance bandwidth and far-field gain in the phantom are 16.4% and -30.3 dB, respectively, at 915 MHz, and 10.2% and -21.2 dB, respectively, at 2.45 GHz. In addition, the communication link is calculated and evaluated based on the specific absorption rate (SAR) of the proposed differential integrated antenna at 1-W input power.