Patent ID: 7577404

Claim:
A high-frequency device comprising a circuit for switching connection to an antenna side circuit and a predetermined transmitting system circuit or receiving system circuit and a high-frequency amplifying circuit connected to said switch circuit, wherein a phase relation between said switch circuit and said high-frequency amplifying circuit is in a state corresponding to a conjugate matching in a fundamental frequency band, while it is in a state corresponding to a nonconjugate matching in n-th frequency bands, wherein n is an integer of 2 or more, and wherein a phase adjustment is carried out so that a phase of an impedance Z 2 in said n-th frequency bands of said switch circuit when viewed from a connection reference plane between said switch circuit and said high-frequency amplifying circuit is within θ 0 ±120°, wherein θ 0 (θ 1 ±180 0 : a position symmetrical with respect to a center on a Smith chart) is a phase opposite to a phase θ 1 by 180°, and θ 1 (−θ) is conjugate to a phase θ of an impedance Z 1 in said n-th frequency bands of said high-frequency amplifying circuit when viewed from said connection reference plane.