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IEEE Transactions on Microwave Theory and Techniques
Volume 48 Number 12, December 2000

Table of Contents for this issue

Complete paper in PDF format

42% High-Efficiency Two-Stage HBT Power-Amplifier MMIC for W-CDMA Cellular Phone Systems

Taisuke Iwai, Member, IEEE Kazuhiko Kobayashi, Member, IEEE Yasuhiro Nakasha, Takumi Miyashita, Member, IEEE Shiro Ohara, Member, IEEE and Kazukiyo Joshin Member, IEEE

Page 2567.

Abstract:

This is the first paper to report on a high-efficiency two-stage heterojunction-bipolar-transistor power-amplifier monolithic microwave integrated circuit (MMIC) for 1.95-GHz wide-band code-division multiple-access (W-CDMA) cellular phone systems. Power amplifiers for W-CDMA systems are required to operate at high efficiency and high linearity over a wide range of output power levels. To obtain high efficiency at low output power (Pout) as well as at the required maximum Pout, and obtain a high linearity at the maximum Pout, we chose near-class-B operation. To improve linearity at a medium Pout range, we suppressed the gain distortion resulting from near-class-B operation by using an adaptive biasing technique. The MMIC exhibited a power-added efficiency of 42%, the highest ever reported, a gain of 30.5 dB, and an adjacent channel leakage power ratio at a 5-MHz offset frequency of - 38 dBc at a Pout of 27 dBm under a supply voltage of 3.5 V with 3.84-Mcps hybrid phase-shift keying modulation.

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