Multi-mode filter having at least one feed line and a phase array of coupling elements

1. A multi-mode cavity filter comprising:

a dielectric resonator body incorporating a piece of dielectric material, the piece of dielectric material having a shape supporting at least two substantially degenerate resonant modes;

a substrate, said dielectric resonator body being coupled to said substrate, said substrate including at least one feed line; and

a phased array of coupling elements between said substrate and said dielectric resonator body, said phased array of coupling elements including a plurality of input couplings and a plurality of output couplings, said plurality of input couplings being distinct from said plurality of output couplings, said plurality of input couplings being used simultaneously for coupling signals received through said at least one feed line to the piece of dielectric material with a phase preselected for each of said input couplings,

wherein the signal received by each of said plurality of input couplings exhibits a specific phase that depends upon a length along said at least one feed line from an input point for the signal.

2. A multi-mode cavity filter according to claim 1 , wherein at least some of the phased array of coupling elements are patches formed on a surface of the piece of dielectric material.

3. A multi-mode cavity filter according to claim 2 , wherein at least some of the patches are of a regular geometric shape.

4. A multi-mode cavity filter according to claim 1 , wherein said at least one feed line includes at least one meander.

5. A multi-mode cavity filter according to claim 1 , wherein at least some of said phased array of coupling elements are magnetic field generating elements.

6. A multi-mode cavity filter according to claim 1 , wherein at least some of said plurality of input couplings are connected to one another in series.

7. A multi-mode cavity filter according to claim 1 , wherein said at least one feed line comprises a primary feed line configured to feed signals to a plurality of secondary feed lines branching off said primary feed line; and

wherein each of the plurality of secondary feed lines is configured to transmit a signal to at least one input coupling.

8. A multi-mode cavity filter according to claim 1 , wherein each one of the phased array of coupling elements is electrically independent from the others.

9. A multi-mode cavity filter according to claim 1 , further comprising an amplitude determination mechanism for determining the amplitude of the signal transmitted along said at least one feed line.

10. A multi-mode cavity filter according to claim 9 , wherein the signals transmitted to each one of the phased array of coupling elements exhibit a respective amplitude that is predetermined.

11. A multi-mode cavity filter according to claim 1 , wherein the phased array of coupling elements is arranged in a substantially symmetrical array.

12. A multi-mode cavity filter according to claim 1 , wherein said plurality of output couplings is arranged to recover signals from the piece of dielectric material.

13. A multi-mode cavity filter according to claim 1 , wherein at least some of said phased array of coupling elements are probes arranged to abut a surface of, or at least partially penetrate a surface of, the piece of dielectric material.

14. A multi-mode cavity filter according to claim 13 , wherein said probes have a substantially circular cross section.

15. A multi-mode cavity filter according to claim 13 , further comprising a shielding element associated with each probe.

16. A method of manufacturing a multi-mode cavity filter, the method comprising:

providing a dielectric resonator body of dielectric material having a shape supporting at least two substantially degenerate resonant modes;

coupling said dielectric resonator body to a substrate, said substrate including at least one feed line; and

providing a phased array of coupling elements between said substrate and said dielectric resonator body, said phased array of coupling elements including a plurality of input couplings and a plurality of output couplings, said plurality of input couplings being distinct from said plurality of output couplings, said plurality of input couplings being used simultaneously for coupling signals received through said at least one feed line to the piece of dielectric material with a phase preselected for each of said input couplings,

wherein the signal received by each of said plurality of input couplings exhibits a specific phase that depends upon a length along said at least one feed line from an input point for the signal.