| 摘要 |
PROBLEM TO BE SOLVED: To obtain a diversity changeover circuit that can optimizes a characteristic of a selected antenna by adjusting the impedance when viewing the circuit from an antenna that is not selected. SOLUTION: A 1st port 5a of an antenna changeover switch 5 is selected at the selection of a 1st antenna 1a, the impedance of the 1st antenna 1a is matched nearly with a characteristic impedance by a 1st antenna matching circuit 2a, the impedance of the antenna changeover switch 5 is nearly equal to that of a reception section 6, the impedance of the circuit connected across the 1st matching circuit 4a is matched with the characteristic impedance and then the impedance when viewing the antenna changeover switch 5 from the 1st matching circuit 4a is matched with the characteristic impedance. When the 1st antenna 1a is not selected, the 1st port 5a of the antenna changeover switch 5 is disconnected and the impedance when viewing the antenna changeover switch 5 from the 1st port 5a is changed.
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