Zhiqing Geng

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A 2.4-GHz energy-efficient transmitter (TX) for wireless medical applications is presented in this paper. It consists of four blocks: a phase-locked loop (PLL) synthesizer with a direct frequency presetting technique, a class-B power amplifier, a digital processor, and nonvolatile memory (NVM). The frequency presetting technique can accurately preset the(More)
This paper presents a novel RFID tag chip with temperature sensor in 0.18μm standard CMOS process. It consists of four blocks: RF/analog front-end circuit, 192-bit non-volatile memory (NVM), temperature sensor and digital baseband circuit. A CMOS UHF rectifier with dynamic bias using switch capacitor is proposed to improve the efficiency of rectification,(More)
A methodology is presented for predicting the phase noise of the ΣΔ Fractional-N Frequency Synthesize that is both accurate and efficient based on sampling the noise voltage in the time domain. An accurate Voltage Control Oscillator (VCO) noise model is presented, including both thermal noise and 1/f noise. The behavioral model provides a(More)
This paper proposes a low power flexible programmable gain amplifier (PGA) with DC Offset cancellation for software defined radio front-ends. PGA consists of three-stage amplifiers which includes variable gain amplifier (VGA) and DC offset cancellation circuits. It uses high-pass filtering (HPF) and continuous-time feedback (CTF) techniques to cancel DC(More)
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