A 1.9-GHz-band GaAs direct-quadrature modulator IC with a phase shifter. - Kazuya Yamamoto; Kosei Maemura; Naoto Andoh; Yasuo Mitsui (IEEE J. Solid State Circuits, 1993)

A single-chip GaAs RF transceiver for 1.9-GHz digital mobile communication systems. - Kazuya Yamamoto; Kosei Maemura; Nobuyuki Kasai; Yutaka Yoshii; Yukio Miyazaki; Masatoshi Nakayama; Noriko Ogata; Tadashi Takagi; Mutsuyuki Otsubo (IEEE J. Solid State Circuits, 1996)

A CDMA InGaP/GaAs-HBT MMIC Power Amplifier Module Operating With a Low Reference Voltage of 2.4 V. - Kazuya Yamamoto; Takao Moriwaki; Hiroyuki Otsuka; Nobuyuki Ogawa; Kosei Maemura; Teruyuki Shimura (IEEE J. Solid State Circuits, 2007)