A Miniaturized WiMAX Band 4-W Class-F GaN HEMT Power Amplifier Module

In this paper, the design and fabrication of a miniaturized 4-W power amplifier for the WiMAX frequency band (2.3 - 2.7 GHz) is presented. The selected active device is a commercially available GaN HEMT chip from TriQuint Semiconducotr Inc., Hillsboro, OR. The optimum input and output impedances of the GaN HEMT at fundamental frequency are extracted using a custom designed tuning jig. A novel output matching network for class-F operation is proposed and designed using the measured impedances. For integration in a small package, the input and output matching networks are implemented using spiral inductors and interdigital capacitors, and their dimensions were determined using electromagnetic simulation. The fabricated power amplifier is 4.4 4.4 mm(2) and has an efficiency above 50% and harmonic suppression above 40 dBc for second and third harmonics at an output power of 36 dBm.