A Silicon-Based Ferrite Loaded Miniaturized On-Chip Antenna with Enhanced Gain for Implantable Bio-Telemetry Applications

To make a truly compact size system on-chip (SoC) device for wireless bio-telemetry application, the design of a miniaturized on-chip antenna (OCA) with enhanced gain becomes a prime challenge in recent time. Unsuitable Si (Silicon) substrate and relatively larger antenna size at lower microwave frequencies make it even more challenging for the researchers. In this work, an OCA is designed on a low resistive (rho = 10 ohm.cm) Si substrate by using standard CMOS technology process. The top metal layer of CMOS layout has been used for designing the antenna to reduce fabrication complexity. By using slot miniaturization technique, the proposed antenna size of lambda(0)/22 x lambda(0)/21.4 mm(2) is achieved and operable at ISM 915 MHz band for biotelemetry applications. A gain enhancement technique for OCA is proposed by introducing a 0.2 mu m thin film of Cobalt Zirconium Oxide (CoZrO) ferrite material, and the gain is enhanced by +12.28 dB with the bandwidth and fractional bandwidth (FBW) of 1.14 GHz and 124%, respectively. The simulation results of the proposed antenna with coating of bio-compatible material show its potential applicability for implantable bio-telemetry applications. An equivalent circuit of the proposed OCA is presented and verified by ADS circuit simulator.