An antenna system includes a dielectric resonator, provided with first and second electrical signal inputs. An electrical signal is fed through the first electrical signal input, and through the second electrical signal input with a significant phase difference, for example in the region of 180°. This has the advantage that the antenna bandwidth is increased, allowing the antenna system to be used in wideband applications.
1. An antenna system, comprising a dielectric resonator and means for simultaneously supplying an electrical signal to first and second points in the dielectric resonator, with a phase difference between said first and second points, such that the first point couples to a desired mode of the dielectric resonator antenna and the second points couples to the desired mode of the dielectric resonator and such that a frequency response of the resonator has two nulls in a return loss characteristic of the frequency response, wherein the means for supplying an electrical signal comprise an electrical feed line, a first pad connected to a surface of the dielectric resonator, and a second pad connected to said surface of the dielectric resonator, and further comprising a microstrip line connecting the first and second pads.
2. An antenna system as claimed in claim 1 , wherein the dielectric resonator comprises slots to allow a magnetic field generated around the electrical feed line to couple into the dielectric resonator.
3. An antenna system as claimed in claim 2 , wherein the electrical feed line comprises a first path leading to a first slot in the dielectric resonator, and a second path leading to a second slot in the dielectric resonator.
4. An antenna system as claimed in claim 3 , wherein the first path terminates underneath the first slot in the dielectric resonator, and the second path terminates underneath the second slot in the dielectric resonator.
5. An antenna system as claimed in claim 1 , wherein the means for supplying an electrical signal comprise probes.
6. An antenna system as claimed in claim 1 , comprising means for supplying the electrical signal to the first and second points with a phase difference in the range of 140°-220° therebetween.
7. An antenna system as claimed in claim 1 , comprising means for supplying the electrical signal to the first and second points with a phase difference therebetween, such that a frequency response of the antenna system has two nulls in its return loss characteristic, spaced such that an operating bandwidth of the antenna system is effectively broadened.
8. An antenna system as claimed in claim 1 , comprising means for supplying the electrical signal to the first and second points with a phase difference therebetween, such that a frequency response of the antenna system has two nulls in its return loss characteristic, spaced such that the antenna system operates as a dual band antenna.
9. An antenna system as claimed in claim 1 , wherein the first pad is connected to the surface of the dielectric resonator at a first end region thereof.
10. An antenna system as claimed in claim 9 , wherein the second pad is connected to the surface of the dielectric resonator at a second end region thereof, opposite the first end region.
11. An antenna system as claimed in claim 9 , wherein the second pad is connected to the surface of the dielectric resonator system at a second region thereof, the position of the second region being chosen such that a desired HEM mode is excited.
12. An antenna system as claimed in claim 1 , comprising a tuning screw located adjacent the dielectric resonator.
13. An antenna system as claimed in claim 1 further comprising at least one additional pad located underneath said surface of the dielectric resonator system to provide support therefor.
14. An antenna system as claimed in claim 1 , wherein the first and second points each couple to a HEM mode of the dielectric resonator.
15. An antenna system as claimed in claim 14 , wherein the first and second points in the dielectric resonator are chosen such that a higher order HEM mode is excited, and such that the antenna effectively forms a solid dielectric array.
16. An antenna system as claimed in claim 15 , wherein an end face of the dielectric resonator acts as a mirror.
17. An antenna system as claimed in claim 16 , wherein said end face of the dielectric resonator is coated with an electrical conductor.
18. An antenna system as claimed in claim 16 , wherein said end face of the dielectric resonator is coated with a metal.
19. A method of operation of an antenna system, comprising a dielectric resonator, the method comprising simultaneously supplying an electrical signal to first and second points in the dielectric resonator, with a phase difference between said first and second points, such that the first point couples to a desired mode of the dielectric resonator and the second points couples to the desired mode of the dielectric resonator, and such that a frequency response of the antenna system has two nulls in a return loss characteristic of the frequency response; wherein supplying an electrical signal comprise supplying the signal through an electrical feed line, connecting a first pad to a surface of the dielectric resonator, and connecting a second pad to said surface of the dielectric resonator, and further connecting the first and second pads with a microstrip line.
20. A method as claimed in claim 19 , comprising coupling the electrical signal to the electric field in the dielectric resonator.
21. A method as claimed in claim 19 , comprising coupling the electrical signal to the magnetic field in the dielectric resonator.
22. A method as claimed in claim 19 , comprising supplying the electrical signal to the first and second points with a phase difference in the range of 140°-220° therebetween.