Theory and Design of Class-J Power Amplifiers With Dynamic Load Modulation
Journal article, 2012

A theory for class-J microwave amplifier operation as a function of drive level and fundamental load impedance is derived. Calculations show that, under appropriate operating conditions, it is sufficient to modulate the transistor load reactance to enable high-efficiency operation (>70%) over a large output power dynamic range (>10 dB) with high transistor power utilization. Such dynamic load modulation (DLM) networks are an ideal application of continuously tunable varactor technologies. Multiharmonic load–pull measurements are performed on a GaN HEMT and experimentally verify the theory of operation. A demonstrator amplifier using an SiC varactor technology is then designed and characterized by static measurements. The amplifier has a peak power of 38 dBm at 2.08 GHz and maintains efficiencies above 45% over 8 dB of power dynamic range. An analysis of the load network losses is performed to show the potential of the class-J DLM transmitter concept.

Energy efficiency

varactors

gallium nitride (GaN)

silicon–carbide (SiC)

power amplifiers

Author

Christer Andersson

GigaHertz Centre

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

David Gustafsson

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Koji Yamanaka

Mitsubishi Electric Corporation

Eigo Kuwata

Mitsubishi Electric Corporation

Hiroshi Otsuka

Mitsubishi Electric Corporation

Masatoshi Nakayama

Mitsubishi Electric Corporation

Yoshihito Hirano

Mitsubishi Electric Corporation

Iltcho Angelov

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

GigaHertz Centre

Christian Fager

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

GigaHertz Centre

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 60 12 3778-3786

Areas of Advance

Information and Communication Technology

Driving Forces

Sustainable development

Subject Categories

Telecommunications

Communication Systems

Electrical Engineering, Electronic Engineering, Information Engineering

Infrastructure

Nanofabrication Laboratory

DOI

10.1109/TMTT.2012.2221140

More information

Created

10/7/2017