Low-Power OOK Transceiver With Auto-Feedback Calibrator in Receiver and Harmonic Mitigation Technique in Transmitter for Implantable Devices

This article presents the design and implementation of a highly integrated, low-power on-off keying (OOK) transceiver for energy-efficient wireless communication in the 2.4 GHz Industrial Scientific Medical band. The receiver integrates a novel single-to-differential envelope detector paired with an auto-feedback calibrator (AFC), thereby enhancing sensitivity while minimizing power consumption and chip area. By eliminating the need for a large-area balun and leveraging the AFC, the receiver optimizes signal detection performance. The transmitter incorporates a current-reused self-mixing voltage-controlled oscillator to reduce energy consumption, along with a quadruple-transconductance power amplifier to suppress second-order harmonic distortion. The entire transceiver is fabricated using TSMC 0.18 µm CMOS technology. For short-range operation at a carrier frequency of 2.45 GHz, the receiver achieves a sensitivity of -38.8 dBm at a 2 Mbps data rate. Meanwhile, the transmitter supplies 16.3 dBm output power and supports data rates of up to 30 Mbps. Operating from a 1.2 V supply, the receiver and transmitter consume only 8.7 µW and 0.856 mW, respectively. Overall, these results yield an energy-per-bit of 4.35 pJ/bit for the receiver and a figure of merit of 10.47 for the transmitter, highlighting the transceiver's suitability for low-power, high-efficiency implantable or wearable applications.