Abstract: A resonator system contains one or more resonator, and has a plurality of degenerate resonant modes. Switching circuitry can be operated for controlling a degree of coupling between the resonant modes, such that resonant properties of the resonator system can be controlled. Where the resonator system includes one resonator, the size of a notch in a conductive patch can be controlled to vary the coupling between the resonant modes within that resonator. Where the resonator system includes multiple resonators, the coupling between the resonant modes in the resonators can be varied. A single device can be tuned as required, in order to provide the desired frequency response properties.

Abstract: A resonator comprises an annular conductor, in the form of a primary annular conductor component and at least one secondary annular conductor component located inwardly of the primary annular conductor component, with the annular conductor components spaced apart from each other. The resonator further comprises controllable switches, for selectively connecting the one or more secondary annular conductor component to the primary annular conductor component, in order to adjust the resonant properties of the resonator.

Abstract: A resonator system contains one or more resonator, and has a plurality of degenerate resonant modes. Switching circuitry can be operated for controlling a degree of coupling between the resonant modes, such that resonant properties of the resonator system can be controlled. Where the resonator system includes one resonator, the size of a notch in a conductive patch can be controlled to vary the coupling between the resonant modes within that resonator. Where the resonator system includes multiple resonators, the coupling between the resonant modes in the resonators can be varied. A single device can be tuned as required, in order to provide the desired frequency response properties.