Browsing by Author "Sun, Yuxiang"

Now showing 1 - 6 of 6
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    A Wirelessly Powered Injection-Locked Oscillator with On-Chip Antennas in CMOS for IOT Sensor Node
    (2016-04-22) Sun, Yuxiang; Babakhani, Aydin
    In recent years, the Internet of Things (IoT) has emerged as the main technology trend. By connecting every physical object embedded with sensors and actuators, the IoT merges with the real physical world to the virtual Internet world. This new network opens up tremendous opportunities in all kinds of applications, ranging from health care to autonomous car design to the oil and gas industry. However, the IoT network also presents many challenges. One important challenge is power source. Regularly changing the batteries of billions of IoT devices seems impossible. Nor can we run with billions of cables to connect these devices. One promising solution is using wireless power. In the past few decades, we have benefited from progessive CMOS technology to shrink the size of the silicon chip. However, as for antenna, there is a fundamental trade off between size, efficiency, and frequency. For IoT systems, a lot of optimization should be done to aggressively shrink the wireless powered chips with on-chip antennas to millimeter size. To address these issues, this thesis presents the first batteryless mm-sized wirelessly powered injection-locked oscillator with on-chip antennas in 180nm SOI CMOS. The chip harvests electromagnetic radiation from a continuous-wave source in the X-band using the on-chip antenna. In addition, the chip is equipped with a broadband injection-locking oscillator that locks to the frequency of the input and produces a synchronized signal at the half frequency of the input. The locked signal is then radiated back by the on-chip dipole antenna. This architecture resolves the conventional self-interference issues in RFID sensors by separating the received and transmitted frequencies. In addition, the locking mechanism improves the phase-noise of the on-chip oscillator to -93dBc/Hz at 100Hz offset.
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    Methods and systems related to remote measuring and sensing
    (2021-06-29) Babakhani, Aydin; Pour, Seyed Mohammad Kazem; Forghani, Mahdi; Sun, Yuxiang; Cherivirala, Yaswanth Kumar; Rice University; United States Patent and Trademark Office
    Remote measuring and sensing. Some example embodiment related to optical energy harvesting by identification device, such as infrared identification device GRID devices. Other embodiments relate to RFID device localization using low frequency source signals. Yet still other embodiments related to energy harvesting by RFID in electric fields in both conductive and non-conductive environments.
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    Methods and systems related to remote measuring and sensing
    (2022-03-01) Babakhani, Aydin; Pour, Seyed Mohammad Kazem; Forghani, Mahdi; Sun, Yuxiang; Cherivirala, Yaswanth Kumar; Rice University; United States Patent and Trademark Office
    Remote measuring and sensing. Some example embodiment related to optical energy harvesting by identification device, such as infrared identification device GRID devices). Other embodiments relate to RFID device localization using low frequency source signals. Yet still other embodiments related to energy harvesting by RFID in electric fields in both conductive and non-conductive environments.
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    Systems and methods for wireless treatment of arrhythmias
    (2021-07-27) Sun, Yuxiang; Babakhani, Aydin; Razavi, Mehdi; Burkland, David; Greet, Brian; John, Mathews; Lyu, Hongming; Rice University; Texas Heart Institute; Baylor College of Medicine; United States Patent and Trademark Office
    Wireless treatment of arrhythmias. At least some of the example embodiments are methods including: charging a capacitor of a first microchip device abutting heart tissue, the charging by harvesting ambient energy; charging a capacitor of a second microchip device abutting the heart tissue, the charging of the capacitor of the second microchip device by harvesting ambient energy; sending a command wirelessly from a communication device outside the rib cage to the microchip devices; applying electrical energy to the heart tissue by the first microchip device responsive to the command, the electrical energy applied from the capacitor of the first microchip device; and applying electrical energy to the heart tissue by the second microchip device responsive to the command to the second microchip device, the electrical energy applied from the capacitor of the second microchip device.
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    Systems and methods for wireless treatment of arrhythmias
    (2023-08-01) Sun, Yuxiang; Babakhani, Aydin; Razavi, Mehdi; Burkland, David; Greet, Brian; John, Mathews; Lyu, Hongming; Rice University; William Marsh Rice University; Texas Heart Institute; Baylor College of Medicine; United States Patent and Trademark Office
    Wireless treatment of arrhythmias. At least some of the example embodiments are methods including: charging a capacitor of a first microchip device abutting heart tissue, the charging by harvesting ambient energy; charging a capacitor of a second microchip device abutting the heart tissue, the charging of the capacitor of the second microchip device by harvesting ambient energy; sending a command wirelessly from a communication device outside the rib cage to the microchip devices; applying electrical energy to the heart tissue by the first microchip device responsive to the command, the electrical energy applied from the capacitor of the first microchip device; and applying electrical energy to the heart tissue by the second microchip device responsive to the command to the second microchip device, the electrical energy applied from the capacitor of the second microchip device.
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    Wirelessly Powered Sensor Design with On-Chip Antenna in CMOS Technology
    (2019-09-23) Sun, Yuxiang; Babakhani, Aydin; Knightly, Edward
    In recent years, we have experienced a significant growth of the Internet of Things (IoT), wireless sensor network (WSN) and bio-implantable devices. There are 7 billion of IoT devices in use in 2018, which starts to surpass the number of the mobile devices. To extend the next level of connectivity from smart phone or tablet to each of the everyday objects, a battery-less small-footprint low-cost IoT circuit with sensing, computation and communication capability is critical for the advancement of the applications. In this thesis, to eliminate the need of battery and miniaturize the system size to millimeter scale, wireless power harvesting front-end with on-chip antenna is utilized to extend the operating distance. The operating frequency of the wireless power link is optimized for mm-sized on-chip antenna to minimize the device size and to achieve a higher received rectified power. Moreover, for wirelessly-powered transmitter design, a frequency-division scheme is adopted to solve the self-interference issue in conventional Radio-Frequency Identification (RFID) system. A duty cycle operation of the circuit is also proposed by utilizing power management unit, which reduces the minimum required harvested power for more power-hungry applications. Based on these methodologies, several wireless-powered CMOS circuits are implemented and tested for different applications. The first chip is a wirelessly-powered dielectric sensor with the size of 3.9 by 0.7mm2. It can detect the dielectric constant of different materials such as oil and epoxy shown on top of the chip. The second chip is targeted for absorption spectroscopy application by using a wirelessly-powered injection-locked oscillator to achieve wide tuning range from 4 to 5 GHz. The third chip is a millimeter sized wirelessly-powered pH sensor together with customized IrOx sensing electrode. The pH sensor transmits a pH-sensitive frequency signal that is converted from the sensed electrode reduction potential. In addition to sensor applications, a wirelessly-powered transmitter with on-chip antenna in 180 nm CMOS is designed, which achieves a data-rate up to 50 Mbps with on-off key modulation scheme. Moreover, a wirelessly-powered miniaturized pacemaker chip in 180 nm CMOS process is also implemented. The total size of the pacemaker chip with PCB package is 16 by 3.8mm2. The in-vivo experiment is demonstrated successfully on a live pig heart, that the heart rate can be tuned from 100 bpm to 172 bpm by the changing the stimulation from the chip.