Patent ID: 7161433

Claim:
A high frequency amplifier for amplifying a high frequency signal using a plurality of amplifier sections, said high frequency amplifier comprising: a constant voltage driven amplifier section using an amplifying element biased by a constant voltage; and a constant current driven amplifier section using an amplifying element biased by a constant current, wherein said constant voltage driven amplifier section and said constant current driven amplifier section are parallelly combined, wherein the amplifying elements comprise a bipolar transistor whose base is biased by the constant voltage and a bipolar transistor whose base is biased by the constant current, the bipolar transistors being formed on a same chip with their bases separated; a collector lead-out pattern for connecting a collector of said bipolar transistor biased by the constant voltage and a collector of said bipolar transistor biased by the constant current to a single collector pad; an emitter lead-out pattern for connecting an emitter of said bipolar transistor biased by the constant voltage and an emitter of said bipolar transistor biased by the constant current to a single emitter pad; a base lead-out pattern for connecting a base of said bipolar transistor biased by the constant voltage to a base pad supplied with the constant bias voltage; and a base lead-out pattern for connecting a base of said bipolar transistor biased by the constant current to a base pad supplied with the constant bias current, wherein said base lead-out patterns and said emitter lead-out pattern are configured such that they have little or no overlapping section.