INTERDIGITATED TRANSMISSION LINE TRANSFORMER AND POWER AMPLIFIER CONTAINING THE SAME

摘要

An interdigitated transmission line transformer is provided to improve efficiency when being used as a matching circuit of a power amplifier for a wireless communication system for converting a differential signal into an in-phase signal by a large coupling coefficient. A primary side transmission line(201a) and a secondary side transmission line(201b) are divided into respectively four and three to be engaged with each other. The four primary side transmission lines(201a) are connected to each other in parallel. The three secondary side transmission lines(201b) are connected to each other in parallel. A transmission line transformer is installed as a part of a matching circuit. A length of a facing part of the primary side transmission line(201a) and the secondary side transmission line(201b) is extended so that a magnetic field formed by current flowing through the primary side transmission line(201a) has influence on the secondary side transmission line(201b), thereby reducing the amount of current induced in the secondary side transmission line(201b).