A Millimeter-Scale Crystal-Less MICS Transceiver for Insertable Smart Pills

An End-to-End Dual ASIC OFDM Transceiver for Ultrasound In-Body Communication

Implanted medical devices need a reliable, secure and low-energy wireless communication link. Ultrasound (US) wave propagation is promising over other techniques due to its lower body attenuation, inherent security and well-studied physiological impact. While US communication systems have been proposed, they either neglect realistic channel conditions or fail to be integrated into small-scale, energy-scarce systems. Therefore, this work proposes a custom, hardware efficient OFDM modem optimized for the diverse needs of ultrasound in-body communication channels. This custom OFDM modem is implemented in an end-to-end dual ASIC transceiver: a 180 nm BCD analog front end and a digital baseband chip in 65 nm CMOS technology. Furthermore, the ASIC solution provides tuning knobs to increase the analog dynamic range, to update the OFDM parameters and to fully reprogram the baseband processing, necessary to adjust for the channel variability. Ex-vivo communication experiments on a 14 cm thick piece of beef achieve 470 kbps with BER 3e-4, while consuming 56 nJ/bit and 10.9 nJ/bit Tx/Rx.

An Energy-Efficient and High-Data-Rate IR-UWB Transmitter for Intracortical Neural Sensing Interfaces

This paper presents an implantable impulse-radio ultra-wideband (IR-UWB) wireless telemetry system for intracortical neural sensing interfaces. A 3-dimensional (3-D) hybrid impulse modulation that comprises phase shift keying (PSK), pulse position modulation (PPM) and pulse amplitude modulation (PAM) is proposed to increase modulation order without significantly increasing the demodulation requirement, thus leading to a high data rate of 1.66 Gbps and an increased air-transmission range. Operating in 6 - 9 GHz UWB band, the presented transmitter (TX) supports the proposed hybrid modulation with a high energy efficiency of 5.8 pJ/bit and modulation quality (EVM< -21 dB). A low-noise injection-locked ring oscillator supports 8-PSK with a phase error of 2.6°. A calibration free delay generator realizes a 4-PPM with only 115 μW and avoids potential cross-modulation between PPM and PSK. A switch-cap power amplifier with an asynchronous pulse-shaping performs 4-PAM with high energy efficiency and linearity. The TX is implemented in 28 nm CMOS technology, occupying 0.155mm2 core area. The wireless module including a printed monopole antenna has a module area of only 1.05 cm2. The transmitter consumes in total 9.7 mW when transmitting -41.3 dBm/MHz output power. The wireless telemetry module has been validated ex-vivo with a 15-mm multi-layer porcine tissue, and achieves a communication (air) distance up to 15 cm, leading to at least 16× improvement in distance-moralized energy efficiency of 45 pJ/bit/meter compared to state-of-the-art.

A Bimodal Low-Power Transceiver featuring a Ring Oscillator-based Transmitter and Magnetic Field-based Receiver for Insertable Smart Pills

This paper presents a novel bimodal, low-power, mm-scale transceiver for insertable smart pills. The proposed PA-less, 915 MHz uplink transmitter (TX) incorporates an 1.21.2 mm² on-chip, non-resonated antenna as part of a current-starved ring oscillator (RO) and directly transmits data by turning the RO on/off. This RO-based uplink TX is implemented in 180 nm CMOS along with a power management unit, which generates all internal reference voltages and supplies from a single battery. The uplink TX achieves a data rate of 33 Mb/s and consumes 210 μW, resulting in an energy efficiency of 6.4 pJ/bit. The orientation-insensitive magnetic field-based downlink receiver (RX) is implemented with an external 3-D magnetic sensor, achieves 0.02 kb/s of data rate limited by our measurement setup, and consumes 270 μW. Wireless measurements in saline over 150 cm and prototype of the 3.213.62.3 mm³ insertable pill are presented.

A 0.66mW 400 MHz/900 MHz Transmitter IC for In-Body Bio-Sensing Applications

A sub-1GHz transmitter (TX) integrated chip (IC) with ultra-low power consumption and moderately high adjacent channel power rejection (ACPR) is presented for in-body bio-sensing applications. The 400 MHz 12-phase digital power amplifier (DPA) is implemented with the proposed 16QAM modulation scheme to improve the energy efficiency. The TX IC also contains a 900 MHz FSK TX realized with a symmetrical edge-combiner, which can be used in the low accuracy mode. A fully digital modulator with band shaping is integrated on the chip for the improvement of ACPR performance. Fabricated in 65-nm CMOS process, the chip occupies an active area of 0.75 mm². Under 0.5 V supply voltage, the TX consumes less than 0.66 mW power consumption while delivering -15 dBm of output power when operating at both bands. The presented TX has an energy efficiency performance comparable to the state-of-the-arts low power designs, with the measured average energy consumption of 64.5/220 pJ/bit, and the measured figure-of-merit (FoM) of 2.04/6.98 nJ/(bit · mW) for the two bands. Compared with the state-of-the-arts sub-1mW designs in literatures, the ACPR is improved by at least 13 dB.