Metamaterial antenna arrays with radiation pattern shaping and beam switching

1. A communication system, comprising:

a ground electrode; and

an antenna structure, comprising

an input portion;

a radiating portion;

a capacitance element formed between the input portion and the radiating portion; and

a shunt inductive element coupled between the radiating portion and the ground electrode, the shunt inductive element forming a shunt inductance from the radiating portion to the ground electrode, wherein the capacitance element forms a series capacitance between the input portion and the radiating portion, and wherein the communication system forms a Composite Right/Left-Handed (CRLH) structure having the series capacitance and the shunt inductance.

2. The communication system as in claim 1 , wherein the ground electrode is formed in a first substrate layer and the radiating portion of the antenna structure is formed in a second substrate layer separated from the first substrate layer by a dielectric layer, and wherein the ground electrode does not substantially overlap a footprint of the radiating portion of the antenna structure.

3. The communication system as in claim 2 , wherein the antenna structure is a monopole antenna structure.

4. The communication system as in claim 2 , wherein the antenna structure is a printed conductive structure on a dielectric substrate.

5. The communication system as in claim 3 , wherein the capacitance element is formed by a gap in the printed conductive structure between the input portion and the radiating portion of the antenna structure so as to form a capacitive coupling therebetween.

6. The communication system as in claim 2 , wherein the ground electrode is isolated from the input portion of the antenna structure.

7. The communication system as in claim 2 , wherein the shunt inductive element comprises a conductive line.

8. The communication system as in claim 7 , wherein the series capacitance has a corresponding series resonance frequency, and the shunt inductance has a corresponding shunt resonance frequency.

9. The communication system as in claim 7 , wherein the dimensions and placement of the ground electrode, radiating portion, and shunt inductive element determine an operating bandwidth of the antenna structure.

10. The communication system as in claim 7 , wherein the antenna structure has a first resonant frequency, and wherein the communication system has a plurality of resonant frequencies.

11. The communication system as in claim 10 , wherein the dimensions and placement of the ground electrode, radiating portion, and shunt inductive element determine the shunt resonance frequency.

12. The communication system as in claim 2 , wherein the dimensions and placement of the radiating portion and input portion determine the series resonance frequency.

13. The communication system as in claim 2 , further comprising:

a plurality of antenna structures each coupled to at least one switching element, wherein each switching element activates at least one of the plurality of antenna elements in response to a switching control signal, and

wherein the at least one switching element is further coupled to a Radio Frequency (RF) transceiver module.

14. The communication system as in claim 13 , further comprising:

a pattern shaping circuit to supply a radiation transmission signal to the plurality of antenna structures, wherein the pattern shaping circuit splits a received signal into different antenna feed signals to create a radiation pattern.

15. The system as in claim 14 , wherein the pattern shaping circuit generates an amplitude phase combination for each antenna structure.

16. The system as in claim 14 , wherein the pattern shaping circuit comprises a phase shifting circuit including a transmission line structure having a series capacitance and a shunt inductance.

17. The system as in claim 16 , wherein the phase shifting circuit is a directional coupler.

18. The system as in claim 17 , wherein the directional coupler is a multi-port microwave directional coupler, and wherein the phase shifting circuit provides isolation between the plurality of antenna structures.

19. The system as in claim 18 , wherein the directional coupler provides offset to at least one antenna feed signal so as to generate an orthogonal radiation pattern set to input portions of multiple antenna structures.

20. The system as in claim 16 , wherein the phase shifting circuit comprises an electromagnetic band gap structure.

21. The communication system as in claim 14 , further comprising:

a beam switching controller responsive to a feedback control signal from the RF transceiver module to produce the switching control signal,

wherein the switching control signal initiates one of a plurality of operating modes, including a Multiple Input Multiple Output (MIMO) operation mode to find directions of multipath links and lock the plurality of antenna structures to generate antenna patterns in these directions.

22. The communication system as in claim 21 , wherein the pattern shaping circuit and the beam switching controller are configured to selectively direct at least one radiation transmission signal to at least one antenna structure at a time.