Xuebei Yang

A Single-Chip Electron Paramagnetic Resonance Transceiver in 0.13-

We report the first absorption-based single-chip transceiver for electron paramagnetic resonance (EPR) spectroscopy in silicon. The chip is implemented in a 0.13-μm SiGe BiCMOS process technology. The transmitter generates and delivers a continuous-wave microwave signal with a frequency range from 895 to 979 MHz and the receiver adopts a direct-conversion architecture. Based on the single-chip transceiver and a printed-circuit-board-based planar resonator, an EPR spectrometer is assembled and tested. The spectrometer successfully measures the EPR response from samples including 2,2-Diphenyl-1-Picrylhydrazyl powder, Fe3O4 nanoparticles, and Fe2O3 nanoparticles.

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This paper presents a miniaturized EPR spectrometer based on a single-chip transceiver. Utilizing a novel on-chip self-interference cancellation circuit, the electromagnetic coupling from the transmitter (TX) to the receiver (RX) is minimized, allowing simultaneous achievement of large TX output power and low RX noise figure (NF). In the measurement, the RX achieves a NF of 3.1 dB/6.3 dB at 10 MHz/50 kHz baseband frequencies, when the TX and cancellation circuits are turned off. The measured flicker noise corner is 60 kHz, more than 10× lower than the prior work. Moreover, for the first time, the operation of the RX and cancellation circuit is demonstrated when a co-integrated TX is operating at the same time and frequency, while producing >20 dBm output power. When the TX and cancellation circuits are turned on, at -10 dBm interference power, the measured NF is 6.8 dB/11.1 dB at 10 MHz/50 kHz baseband frequencies. This is lower by 5.6 dB/9.6 dB at 10 MHz/50 kHz baseband frequencies, compared to the NF with the cancellation circuit off at the same interference power. The transceiver chip is implemented in IBM 0.13 μm BiCMOS process and consumes a power of 2 W. Utilizing this transceiver, an electron paramagnetic resonance (EPR) spectrometer is built and tested. It is observed, through measurement, that the interference cancellation circuit increases the signal-to-noise ratio (SNR) of the EPR signal by 7 dB at -10 dBm interference power. Compared to prior work, the reported EPR spectrometer improves the sensitivity of the system by 25 dB.

m SiGe BiCMOS

In this letter, we present a novel receiver for time transfer that achieves picosecond accuracy through a line-of-sight link. The receiver is based on a fully integrated optically locked voltage controlled oscillator (OL-VCO) and is implemented in a commercial CMOS process. The design of optical photodiodes integrated with the OL-VCO is explained in detail. It is demonstrated that in the locked mode, the OL-VCO can be synchronized with a 1.3-GHz RF source through a free-space optical link. The free-space synchronization improves the phase noise of the OL-VCO by 25 dB at 100-Hz offset frequency. It is shown that a time transfer accuracy of picosecond can be achieved over a distance of 1.5 m. This represents more than two orders of magnitude improvement compared with the prior art.

A Full-Duplex Single-Chip Transceiver With Self-Interference Cancellation in 0.13

A 4.6-5.35GHz transceiver with active self-interference cancelation is reported. The active cancelation circuit cancels up to 38dB of TX leakage at 10kHz offset from the RX signal. It increases the interference P1dB from -25dBm to -8dBm, and RX gain by 15dB. When the transceiver is utilized in a magnetic resonance spectroscopy system, the SNR improves by 15dB. Furthermore, in addition to the traditional method of B0-sweep, for the first time, the method of frequency-sweep is demonstrated.

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In this paper, the first fully integrated Optically Locked Voltage Controlled Oscillator (OL-VCO) is reported. The OL-VCO is locked to an RF source through a free-space optical link at λ=850 nm. In the locked mode, the OL-VCO achieves an RMS jitter of 1.6 psec with 16 averaging. It also improves the phase noise by 25 dB at 100 Hz offset frequency. The wireless synchronization is achieved at a distance of 1.5 m, representing more than two orders of magnitude improvement compared to the prior art.

m SiGe BiCMOS for Electron Paramagnetic Resonance Spectroscopy

Microwave circuitry for electron paramagnetic resonance (EPR) spectroscopy is implemented in a 0.13μm SiGe BiCMOS process. The chip can operate in both continuous wave (CW) and pulse modes. The frequency is tunable from 770MHz to 970MHz, corresponding to Zeeman magnetic fields from 28mT to 35mT for a free electron. The CW-EPR absorption line of a DPPH powder sample is acquired. The chip consists of a VCO, a PA, an LNA, a down-conversion mixer, baseband amplifiers, and a pulse generation block.

A Free-Space Optically Locked VCO With Picosecond Timing Jitter in 0.18- \(\mu \) m CMOS

A 3.8-4.8GHz single-chip in-band full-duplex (FD) transceiver with self-interference cancellation (SIC) is reported. The RX has a noise figure (NF) of 3.1dB/6.3dB at 10MHz/50kHz IF with TX and SIC off. The 1/f noise corner is 60kHz, more than one order of magnitude lower compared to prior work. Moreover, for the first time, the operation of RX and SIC is demonstrated when a co-integrated TX is active at the same time and generating more than 20dBm output power. When TX and SIC are on, at -10dBm SI power, the NF is 6.8dB/11.1 dB at 10MHz/50kHz IF. This is lower by 5.6dB/9.6dB at 10MHz/50kHz IF compared to the NF with SIC off.

A 4.6–5.35GHz transceiver with 38dB on-chip self-interference cancelation at 10kHz offset frequency

In this work, we report an optical receiver with integrated photodiodes operating at 850nm wavelength. The receiver achieves a data-rate of 2.5Gb/s without using any equalizer. To minimize the area, no inductors are used in the design. The entire receiver occupies an area of 0.38mm2. This represents the smallest optical receiver operating at the Gb/s regime. The chip is fabricated in 0.18μm CMOS SOI process technology.