Abstract
This paper presents a highly efficient multi-band power amplifier (PA) with a novel reconfigurable configuration. It consists of band-switchable matching networks (BS-MNs) and a biasing network (BS-BN) that are available for multi-band operation. BS-MNs with a susceptance block (SB) require a shorter transmission line (TL) than those without the SB at some target impedances. This paper theoretically derives the relationships of the required TL lengths for the BS-MN with or without the SB and the target impedances. The required TL lengths at the target impedances are evaluated numerically in order to discuss the advantages of the proposed configuration. The BS-BN employing switches for band switching can supply DC power to an amplification device without additional DC power dissipation because the DC bias current does not flow through the switches. Numerical analyses confirm that a BS-BN can be configured with low loss in multiple bands. Based on the proposed configuration, a 1/1.5/1.9/2.5-GHz quad-band reconfigurable PA is designed and fabricated employing RF microelectro mechanical systems switches and partitioned low temperature co-fired ceramics substrates. The fabricated 1W-class PA achieves a high output power of greater than 30dBm and a maximum power added efficiency of over 40% in all operating modes.
