Patent ID: 7443262

Claim:
A two-port isolator comprising: a permanent magnet; a ferrite member to which a direct-current magnetic field is applied by said permanent magnet; a first center electrode having one end electrically connected to a first input/output port and the other end electrically connected to a second input/output port, said first center electrode being provided on said ferrite member; a second center electrode having one end electrically connected to the second input/output port and the other end electrically connected to a ground port, said second center electrode being arranged on said ferrite member so as to intersect with said first center electrode, with said first center electrode and said second center electrode being electrically insulated from each other; a first matching capacitor electrically connected between the first input/output port and the second input/output port; a resistor electrically connected between the first input/output port and the second input/output port; a second matching capacitor electrically connected between the second input/output port and the ground port; a first input/output terminal electrically connected to the first input/output port; a second input/output terminal electrically connected to the second input/output port; and an inductor electrically connected in series between the first input/output port and said first input/output terminal; wherein one of the first input/output port and the second input/output port defines an input port, and the other of the first input/output port and the second input/output port defines an output port; and an intersection angle between said first center electrode and said second center electrode is less than about 90 degrees so as to set a susceptance part of an admittance of the first input/output port to a negative value in a pass-band center frequency.