Design of 400-MHz Energy-Efficient RF Transceivers for Bio-medical Implantable Applications
Date Issued
2009
Date
2009
Author(s)
Liu, Yao-Hong
Abstract
A low-power radio transceiver designed for implantable medical applications is presented in this dissertation. These transceivers operate at around 400-MHz band and utilize different modulation schemes and data rate between downlink and uplink. A low-data-rate ASK RX is presented for downlink reception; while high-data-rate GFSK, OQPSK and HS-OQPSK TXs are demonstrated for uplink transmission. Chapter 1 and Chapter 2 will firstly discuss the targeted medical applications as well as the design requirements for the medical transceivers.n Chapter 3, several low-power transceiver architectures are introduced, including a super-regenerative receiver, mixer-based and PLL-base direct-modulation transmitters.ownlink reception adopted a super-regenerative ASK RX with a proposed Delta-Sigma Pulse-Width-Digitizer (DS-PWD) will be presented in Chapter 4. The DS-PWD can be considered as a pulse-width-domain counterpart of a conventional Delta-Sigma modulator which can suppress quantization jitter by 22 dB and achieve a pulse-width detection resolution of 0.23 ns. The whole receiver consumes 900 uW. With a 156-kbps data rate, the RX achieves -78-dBm sensitivity. hapter 5 and Chapter 6 will then present a MUX-based dual-mode uplink TX. First, a Sigma-Delta Phase Rotator (SD-PR) designed for G/FSK uplink transmission is discussed in Chapter 4. By properly combining the multi-phase signals from the PLL output, the SD-PR can effectively synthesize frequency modulation signals with fine-resolution frequencies. The proposed G/FSK TX consumes 9 mW and delivers -11-dBm output power. With a maximum data rate of 6-Mbps, the G/FSK TX achieves 1.5-nJ/bit energy efficiency. Chapter 6 presents an energy-efficient OQPSK TX which can also be implemented with the SD-PR proposed in Chapter 5, by directly selecting one of the quadrature phases through the Phase MUX. The whole OQPSK TX dissipates 3.5 mW. With a maximum data rate of 17.5 Mbps, the OQPSK TX achieves an energy efficiency of 200 pJ/bit and is capable of delivering an output power up to -8 dBm.n order to further improve the spectral efficiency of previous MUX-based OQPSK transmitter, Chapter 7 proposed a FIR-embedded Phase-MUX which allows to half-sine shape the OQPSK modulation; thus reducing the side-lobe energy of OQPSK modulation. The proposed HS-OQPSK TX (without PLL) consumes 1.4 mW and achieves 25-Mbps data rate. Finally, Chapter 8 will summarize and conclude this dissertation.
Subjects
bio-medical implantable devices
low-power RF transceivers
super-regenerative receivers
sigma-delta
frequency synthesizers
phase-locked loop (PLL)
SDGs
Type
thesis
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