Increase the bandwidth of the power amplifier to 185% of the bandwidth by ferrite transformers

Abstract

ABSTRACT The motivation of this paper increases the bandwidth of power amplifier to multioctave by matching circuit, which consists of ferrite balun, 4:1 transformers and RC network feedback to make atrade-off between gain and VSWR. So this work discusses the design of a push-pull power amplifier demonstrating over more than a decade bandwidth using matching networks to achieve [30–800] MHz bandwidth. Matching transformer techniques can be used in order to minimise the return loss and increase the gain. Modification of the classical topology, based on inductive compensation of the parasitic capacitance of ferrite, has been proposed and used to design a 1:4 transformer. Practically, miss-match and heating is the main concern for broadband performance of high power amplifier. Coaxial cable and ferrite are also used to dissipate the heat (high temperature) resulting from the amplification power, in addition to installing the board on a cooler with appropriate dimensions, so we get the best match and stability. The simulation results are compared with the measurements. The measured results show that 20.5–17.46 dB of gain, 50.5–47.46 dBm of output power, and 50.9 of drain efficiency are delivered.