Waveguide A waveguide for carrying waves by inductive coupling comprises a plurality of resonant elements, the plurality of resonant elements including a first resonant element; a second resonant element; and a coupling section capacitively coupling the first and second resonant elements, wherein the coupling between the first and second elements produces a first pass-band and a second-pass band, different from the first pass-band, the first pass-band being associated with the resonance of the resonant elements and the second pass-band being associated with resonance of the coupling section.
1. A system for carrying waves by inductive coupling, the system comprising:
a metamaterial waveguide, the metamaterial waveguide comprising a plurality of resonant elements, the plurality of resonant elements including:
a first resonant element;
a second resonant element; and
a coupling section capacitively coupling the first and second resonant elements, wherein
the coupling between the first and second elements produces a first pass-band and a second-pass band, different from the first pass-band,
the first pass-band being associated with the resonance of the resonant elements and the second pass-band being associated with resonance of the coupling section.
2. The system of claim 1 , wherein
the first resonant element forms a first major loop and the second resonant element forms a second major loop, and
the coupling section forms a minor loop such that respective portions of each of the first and second major loops is shared with the minor loop.
3. The system of claim 2 , wherein each of the shared portions includes a capacitor.
4. The system of claim 1 , wherein the waves are forward propagating.
5. The system of claim 1 , wherein an electrical contribution to the coupling between the first and second resonant elements dominates a magnetic contribution to the coupling between the first and second resonant elements.
6. The system of claim 1 , wherein:
the first resonant element has the same frequency as the second resonant element, and
the coupling section resonates with a resonant frequency different from the resonant frequency of the first and second resonant element.
7. The system of claim 1 , wherein the coupling section comprises one or more coupling capacitors connected between the first and second resonant elements.
8. The system of claim 1 , comprising a one-dimensional array of coupling sections, each consecutive pair of resonant elements having a respective coupling element capacitively coupling the pair of resonant elements.
9. The system of claim 1 , comprising a two-dimensional array of coupling sections, each pair of neighbouring resonant elements having a respective coupling element capacitively coupling the pair of resonant elements.
10. A system comprising:
the system of claim 1 ; and
a communication unit, wherein
the communication unit comprises:
an IO resonant element that is arranged to transmit and/or receive a signal to/from the first resonant element by inductively coupling to the first resonant element, and
a signal source and/or destination conductively connected to the IO resonant element.
11. A method of transporting a signal in a metamaterial waveguide by inductive coupling, the method comprising:
receiving the signal at a first resonant element or a coupling section; and propagating the signal to a second resonant element, wherein
the first and second resonant elements are capacitively coupled by the coupling section,
the coupling between the first and second elements produces a first pass-band and a second-pass band, different from the first pass-band,
the first pass-band being associated with the resonance of the resonant elements and the second pass-band being associated with resonance of the coupling section, and
the first and second resonant elements and the coupling section form at least part of the metamaterial waveguide for propagating the signal by inductive coupling.
12. The method of claim 11 , wherein the signal is received by the first resonant element or the coupling section from an element external to the metamaterial waveguide.
13. The method of claim 11 , wherein the signal is received by the first resonant element or the coupling section from a further resonant element or further coupling section of the metamaterial waveguide.