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keikawa/README.md

👋 Hi there

I am Keisuke Kawahara, a Ph.D. student at Yokohama National University, Japan. My interests include integrated circuit design, silicon photonics, optical communication, microwave theory, and signal processing.

🎓 Education

  • 2016-04-01 to 2020-03-31: Bachelor's Degree in Electrical Engineering, Tokyo University of Science, Noda, Chiba, Japan
  • 2020-04-01 to 2022-03-31: Master's Degree in Electrical Engineering, Tokyo University of Science, Noda, Chiba, Japan
  • 2022-04-01 to present: Ph.D. in Progress, Yokohama National University, Yokohama, Kanagawa, Japan

🛠️ Chip Gallery

Analog Multiplexer

Analog Multiplexer (AMUX)

The image-rejection analog multiplexer extends signal bandwidth by three times through a combination of digital signal processing and analog multiplication. (K. Kawahara et al., IEEE Trans. Microw. Theory Tech., vol. 71, no. 1, pp. 22–34, Jan. 2023.)

Active Balun

Active Balun

The active balun converts single-ended signals to differential signals. A small chip area and low imbalance characteristics over a wide bandwidth were demonstrated. (K. Kawahara et al., IEEE Trans. Circuits Syst. I: Regul. Pap., vol. 70, no. 6, pp. 2317–2330, Jun. 2023.)

Distributed Amplifier

Differential Distributed Amplifier

The distributed amplifier operates over a wide bandwidth ranging from DC to tens of gigahertz. The use of coupling inductors halves the area of differential distributed amplifiers. (K. Kawahara et al., IEICE Trans. Electron., vol. E106.C, no. 11, pp. 669–676, Nov. 2023.)

Temperature Sensor

CMOS Temperature Sensor

The trimless temperature sensor is based on an open source design rule and is freely reusable. (GitHub repository.)

Operational Amplifiers

CMOS Operational Amplifier

The class-AB CMOS operational amplifier consumes only 7.7 µA and has a slew rate of 1 V/µs for a 1-nF load. (Slides for 2021 and 2020.)

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