Wideband Class-F-1 Power Amplifier With Dual-/Quad-Mode Bandpass Response

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Original languageEnglish
Article number9040910
Pages (from-to)2239-2249
Journal / PublicationIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number7
Online published18 Mar 2020
Publication statusPublished - Jul 2020


Bandpass power amplifiers (PAs) are typically implemented by a cascade of second-order topologies. To achieve a wide and flat passband response, the number of resonators must be increased, which leads to large size, high loss and low efficiency, especially at high frequencies. In this paper, a wideband Class-F-1 PA based on a microstrip multimode bandpass impedance transformer (BPIT) is proposed. The modified quad-mode BPIT operation enables the creation of multiple transmission poles using only a single resonator, thus simultaneously achieving a flat wideband response in a small size. In addition, the drain bias and input feed line of the BPIT are arranged to satisfy the harmonic-impedance requirement of the Class-F-1 amplifier. Two PA prototypes have been designed, fabricated, and measured, which exhibit desirable filtering characteristics centered at 3.5 and 3.6 GHz for 5G applications. The fabricated dual- and quad-mode circuits demonstrate large-signal gains of 11.5 dB and 12.6 dB, maximum power added efficiencies (PAEs) of 67.4% and 66.3%, respectively and, with output powers greater than 38.5 dBm. For operation with a PAE larger than 60%, the PAs achieve bandwidths of 150 and 250 MHz, respectively.

Research Area(s)

  • Bandpass response, Class-F-1power amplifier, impedance transformer, multimode resonator

Citation Format(s)