Patent ID: 8847681
Filing Date: 2014-09-30
Classification: H01P,H03F

Abstract:
1. A combiner for a Doherty amplifier, for being connected to output terminals of the Doherty amplifier including a carrier amplifier and a peak amplifier and combining an output signal from the carrier amplifier and an output signal from the peak amplifier, the combiner comprising: a first input terminal for being supplied with the output signal from the carrier amplifier; a second input terminal for being supplied with the output signal from the peak amplifier; an output terminal for outputting a signal obtained by combining the output signal from the carrier amplifier and the output signal from the peak amplifier; a combining point for combining the output signal from the carrier amplifier and the output signal from the peak amplifier; a first λ/4 line connected between the first input terminal and the combining point; a second λ/4 line connected between the combining point and the output terminal; signal monitoring means for monitoring at least one of a signal flowing from the first input terminal to the combining point, a signal flowing from the second input terminal to the combining point, and a signal flowing from the combining point to the output terminal; and a dielectric substrate comprising a plurality of stacked dielectric layers, wherein the signal monitoring means comprises a directional coupler, and the directional coupler has a third λ/4 line electromagnetically coupled to one of the first λ/4 line or the second λ/4 line that is to be monitored, a monitor terminal connected to an end of the third λ/4 line, and a termination resistor connected to another end of the third λ/4 line, wherein at least the first input tell final, the second input terminal, the output terminal and the monitor terminal are disposed on surfaces of the dielectric substrate, and the first λ/4 line, the second λ/4 line and the third λ/4 line are disposed in the dielectric substrate, and wherein an inner-layer shield electrode is disposed in the dielectric substrate, the inner-layer shield electrode lying between the first λ/4 line and the second λ/4 line, and the third λ/4 line lying on a side of the one to be monitored of the first λ/4 line and the second λ/4 line.