Study And Design On Implantable Wireless Powered Carrier Wave Tracking UWB-BPSK Transmitter

With the rapid development of wireless communication integrated circuit and medical electronics techniques,the implantable microelectronics aiming at physiological medical research and biomedical monitoring has become a new research field gradually.Compared with the narrowband wireless communication technique,the ultra-wideband(UWB)has the advantages of high data rate,large channel capacity and low power consumption,these advantages are suitable for the multi-channel,high-speed and high-precision transmission of the bioelectrical signals.Moreover,wireless power technique provides a possibility for the implantable electronics devices to work without battery in vivo environment.Since the implantable environment provides extremely limited energy and space to in-vivo devices,the power,complexity,volume and efficiency become the focuses and key challenges of UWB wireless communication technology applied in this field.In this thesis,a system solution of narrowband wireless power transmission within the frequency spectrum notch generated by the UWB-BPSK signal have been studied to realize the UWB-BPSK frequency signals and narrowband wireless power transmission in the same frequency band.Based on 0.18 ?m CMOS technology,an implantable wireless powered carrier wave tracking UWB-BPSK transmitter chip has been implemented,the proposed transmitter chip includes: tunable pulse width bipolar Gaussian monocycle pulse generator,tunable bandwidth carrier wave recovery and tracking loop applied with novel transconductance-capacitor(OTA-C)loop filter,and wireless powered circuit applied with multi-stage rectifiers with the function of substrate bias voltage dynamic adjustment.The main research works and innovations are as follows:A carrier wave tracking UWB-BPSK modulation method is proposed.Based on the proposed modulation method,a system solution of narrowband wireless power transmission within the frequency spectrum notch generated by the UWB-BPSK signal have been studied.The frequency spectrum notch of UWB-BPSK signal generated with the proposed method is located at the center frequency which is same as the frequency of narrowband power signal.The frequency of narrowband power signal is same as the center frequency of the UWB-BPSK signal all the time,therefore,the narrowband power signals are still in the frequency spectrum notch to realize the UWB signals and narrowband signals transmission simultaneously in the same frequency band.A bipolar Gaussian monocycle pulse generator with the functions of tunable pulse width and baseband component reverse compensation is proposed and implemented.The baseband narrow pulse width can be tuned with DC voltage and the Gaussian monocycle pulse can be combined with the proposed technique of baseband component reverse compensation.Without using the filter consisted of on-chip inductor and capacitors,the bipolar Gaussian monocycle pulses with excellent time-domain waveform and spectrum efficiency are generated.Since the proposed generator works at alternating mode,the power consumption is lower than other researches.The measured results of proposed generator indicate that the bipolar Gaussian monocycle pulse with pulse interval of 200 MHz is generated successfully at low power cost of 1 mW(unit bit energy consumption is 5 pJ/bit),and the range of narrow pulse width is 0.7 ns to 2.5 ns.A tunable transconductance and wide input linear range operational transconductance amplifier(OTA)consisted of self-cascode with bulk-terminal cross-coupled and low-voltage cascode current mirror is presented.Based on the proposed OTA,a tunable bandwidth and high linearity OTA-C filter applied in the carrier wave recovery and tracking loop is designed and implemented.The conventional passive RC filter could be replaced by the proposed OTA-C filter which loop bandwidth could be tuned continuously and linearly with DC voltage to optimize the phase locking time and output phase noise of the carrier wave recovery and tracking loop.The measured results of proposed carrier wave recovery and tracking loop chip indicate that the tunable loop bandwidth range is 100 KHz to 2 MHz,output signal power is-5.94 dBm @ 400 MHz,output phase noise is-103.3 dBc/Hz @ 1 MHz and the phase locking time is 8 ?s.An antenna-rectifier co-design method is presented.Based on the proposed method,the antenna could be design first to meet the requirement of the in-vivo devices and its indexes could be used as the design reference of the multi-stage rectifiers to realize high power conversion efficiency(PCE).Moreover,a novel CMOS gate cross-connected rectifier with the function of substrate bias voltage dynamic adjustment to avoid the latch-up.The measured results of proposed wireless power circuit chip indicate that the maximum PCE of multi-stage rectifiers is 63.7 %.The regulated output voltage is 1.8 V and the received power is 10 mW at the frequency range of 400 MHz to 405 MHz.The proposed implantable wireless powered carrier wave tracking UWB-BPSK transmitter chip is designed and implemented.The measured results indicate that the received power of the transmitter chip is 10 mW at frequency of 400 MHz and distance of 5 cm.The data rate of proposed transmitter chip is 100 Mbps and the frequency spectrum notch is generated at 400 MHz with the depth and bandwidth of the notch are 18.9 dB and 2 MHz,respectively.The total consumption is 8.1 mW which is below the received power.In summary,the results of this thesis not only can be used as a reference for the research of biomedical implantable high-speed wireless communication,but also for the UWB-narrowband coexistence communication application in the limited frequency band.