Patent ID: 6366564
Filing Date: 2002-04-02
Classification: H01P,H03H,H04B

Abstract:
A diplexer separating a signal into two frequency bands, comprising:a first terminal, a second terminal, and a common terminal; a low-pass filter, coupled between said first terminal and said common terminal, whose passband is a first band, a band-pass filter, coupled between said common terminal and said second terminal, whose passband is a second band which is higher in frequency than said first band; a first matching circuit, coupled between said low-pass filter and said common terminal, for raising impedance of said first matching circuit in said second band; and a second matching circuit, coupled between said common terminal and said band-pass filter, for raising impedance of said second matching circuit in said first band, wherein at least two layers of a high-dielectric layer and low-dielectric layer are laminated, said band-pass filter and said second matching circuit are formed in said high-dielectric layer, and said low-pass filter and said first matching circuit are formed in said low-dielectric layer.