Digital PA with voltage-mode topology using envelope delta-sigma modulation

作者：Wentzel Andreas^*; Hori Shinichi; Hayakawa Makoto; Kunihiro Kazuaki; Heinrich Wolfgang

来源：International Journal of Microwave and Wireless Technologies, 2013, 5(3): 285-292.

DOI：10.1017/S1759078713000457

• Microwave power amplifier
• Class-S
• Voltage-mode
• Envelope delta-sigma
• Modulation
• GaN
• MMIC

This paper reports on digital transmitter architecture for the 450 MHz band using an envelope delta-sigma modulator realized in CMOS and a voltage-mode class-S (VMCS) power amplifier (PA) based on GaN monolithic microwave integrated circuits (MMICs). The class-S PA is characterized for narrowband single-tone signals and a single-as well as a four-carrier downlink wideband code division multiple access (WCDMA) signal with a peak-to-average power ratio of 7.5 dB. Using single-tone excitation the PA shows a maximum drain efficiency of 86% and a peak output power of 4.4 W. At 6 and 10 dB back-off, 59 and 36% efficiency are achieved, respectively. With the single- and four-carrier WCDMA input signals maximum drain efficiencies of 64 and 53% are reached, respectively, and peak output power is 0.7 W. The adjacent channel leakage ratio shows values of about -34 dBc (5 MHz) and -38 dBc (10 MHz) for single-carrier WCDMA excitation. This is the first complete VMCS PA chain characterized with standard communication signals.

• 出版日期2013-6