US 6,452,465 B1 · High quality-factor tunable resonator

Abstract

A high quality-factor, tunable radio frequency or microwave resonator is disclosed. The resonator includes one or more microelectromechanical switches positioned along its length. The switches are comprised of metal membrane bridges spanning the microstrip resonator. The bridges are connected to radial stubs that comprise reactive loads. An electrostatic potential differential between the bridge and microstrip resonator causes the bridge to collapse, thereby coupling a radial stub to the microstrip. The imposition of the reactive loads on the resonator causes the resonant frequency to change. Multiple resonators employed in a filter configuration can be variably coupled using microelectromechanical bridges that engage or disengage capacitive air gaps between two microstrip lines, to control filter bandwidth over wide tuning ranges.

Claims14

Dependent claims

A tunable resonator for use in filtering radio frequency electromagnetic signals, which resonator is comprised of:

a microstrip conductor fabricated on a dielectric substrate;
a microelectromechanical bridge that spans the microstrip conductor, the bridge assuming either a resting state in which the bridge is not coupled to the microstrip, or a collapsed state in which the bridge is coupled to the microstrip;
a bias circuit connected to the microelectromechanical bridge that can impose an electrostatic potential differential between the bridge and the microstrip to cause the bridge to enter its collapsed state;
an open radial stub connected to the bridge, such that the stub is coupled to the microstrip when the bridge is in the collapsed state, and the stub is not coupled to the microstrip when the bridge is in the resting state;
whereby the frequency to which the resonator is tuned is determined by the state of the microelectromechanical bridge.

2 more elements

A tunable filter for filtering a radiofrequency electromagnetic signal, the filter comprising:

a primary microstrip line on which the radiofrequency electromagnetic signal is conducted;
one or more resonators, where each resonator is comprised of a resonator microstrip line, a radiofrequency coupling mechanism that conveys electromagnetic energy between the resonator microstrip and the primary microstrip, one or more reactive loads, a radiofrequency switch associated with each one of the one or more reactive loads that alternatively couples the switch's associated reactive load to the resonator microstrip while in a closed state, or decouples an associated reactive load from the resonator microstrip while in an open state;
a control circuit connected to each radiofrequency switch that places each switch into either a closed or an open state.

Dependencies are inferred from the claim text.

High quality-factor tunable resonator

Life of this patent

High quality-factor tunable resonator

Life of this patent

Abstract

Claims14