A Wideband and Compact GaN MMIC Doherty Amplifier for Microwave Link Applications
Journal article, 2013

This paper addresses the limitations and difficulties, in terms of DC-current density restrictions, and process limitations, associated with implementing impedance inverters with high characteristic impedance for monolithic microwave integrated circuit (MMIC) Doherty power amplifiers (DPAs). It is theoretically shown that impedance inverters with high characteristic impedance can be realized by utilizing the output capacitance of the active devices, together with a compact Tee-network of transmission lines with feasible linewidths. The utility of the impedance inverter is proven by design and fabrication of a GaN MMIC-DPA for microwave link applications. Continuous wave (CW) measurements demonstrate a maximum output power of 35 +/- 0.5 dBm over a frequency range of 6.6-8.5 GHz. The power added efficiency (PAE) in 9 dB output power back-off (OPBO) is better than 30% in a frequency range of 6.7-7.8 GHz. Moreover, linearized modulated measurements, employing a 10 MHz 256-QAM signal with 7.8 dB peak to average power ratio (PAPR), demonstrate higher than 35% average PAE, with 27.5 +/- 0.2 dBm average output power, and an adjacent channel power ratio (ACPR) less than -45 dBc, across a 6.8-8.5 GHz frequency range. The fabricated chip-size measures 2.1 mm x 1.5 mm.

Doherty

high efficiency

Broadband amplifiers

MMIC

GaN

high-efficiency

microwave

power

gallium nitride

Author

David Gustafsson

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Jessica Chani Cahuana

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

Dan Kuylenstierna

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Iltcho Angelov

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Christian Fager

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 61 2 922-930

Areas of Advance

Information and Communication Technology

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TMTT.2012.2231421

More information

Created

10/7/2017