Multirole circuit element capable of operating as variable resonator or transmission line and variable filter incorporating the same

摘要

A variable resonator includes a first transmission line 101, a second transmission line 102 and a plurality of switch circuits 150. The electrical length of the first transmission line 101 is equal to the electrical length of the second transmission line 102. The characteristic impedance for the even mode of the first transmission line 101 is equal to the characteristic impedance for the even mode of the second transmission line 102. The characteristic impedance for the odd mode of the first transmission line 101 is equal to the characteristic impedance for the odd mode of the second transmission line 102. Each switch circuit 150 is connected to any of the first transmission line 101 and the second transmission line 102, and one of the switch circuits 150 is turned on.

主权项

1. A multirole circuit element, comprising:
a first transmission line connected at one end and the other end thereof to an input line and an output line, respectively a second transmission line having an electrical length equal to an electrical length of said first transmission line and connected at one end and the other end thereof to said input line and said output line, respectively; and one or more switch circuits, wherein a characteristic impedance for an even mode and a characteristic impedance for an odd mode of said first transmission line are uniform in a length direction of said first transmission line, a characteristic impedance for an even mode and a characteristic impedance for an odd mode of said second transmission line are uniform in a length direction of said second transmission line, the characteristic impedance for the even mode of said first transmission line is equal to the characteristic impedance for the even mode of said second transmission line, the characteristic impedance for the odd mode of said first transmission line is equal to the characteristic impedance for the odd mode of said second transmission line, and each of said one or more switch circuits is connected to only either one of said first transmission line and said second transmission line at a point thereon except for said one end and the other end thereof, thereby allowing the multirole circuit element to be capable of selectively operating as any one of at least a resonator and a transmission line depending on an on/off state of said one or more switch circuits.