An efficiency-enhanced power combining and recycling network for LINC power amplifiers

Abstract

Linear amplification using nonlinear components (LINC) is one of the various methods to provide high power amplifier efficiency and, at the same time, present good linearity. In this method, two constant amplitude phase-modulated signals, amplified respectively by two identical high-efficiency power amplifiers, are summed to achieve power amplification. During the summing of the signals using a combiner, like the Wilkinson combiner, energy is lost as heat through the isolation resistor. The design and implementation of a modified Wilkinson power combiner for LINC power amplifiers are investigated in this thesis. The goal is to increase the power efficiency of the LINC power amplifier by recycling the power that would be dissipated as heat in the resistor. The work includes separate designs for three components: (i) a traditional Wilkinson combiner, (ii) a Balun, and (iii) a power recycling rectifier. An RF power summing and RF power recycling network are formed by integrating the three components. The overall performance is measured. The design and simulation are conducted for the Wilkinson combiner with an LC Balun replacing the resistor. The fabricated prototype demonstrates a maximum power efficiency of 93.3% at the RF summing port and a maximum efficiency of 91.7% at the RF difference port. A rectifier composed of two sub-rectifier and one impedance compression network is simulated, and the performance is verified with a fabricated prototype. The proposed rectifier can achieve 66.2% of the maximum rectifying efficiency with 20 dBm RF input signal power at 3.5GHz. It is also observed that from 6 dBm to 24 dBm, the designed circuit presents a rectifying efficiency greater than 40%. The overall performance is evaluated by cascading the designed Wilkinson combiner, the Balun, and the rectifier. 53.5% of DC power recycling efficiency is observed at 2.7GHz with 20 dBm RF input signal power at the Wilkinson input ports. It is also observed that from 8 dBm to 20 dBm, the designed circuit presents a rectifying efficiency greater than 40%.

Date	7 Feb 2024
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Ammar B. Kouki (Supervisor)