Communication system and communication apparatus

1. A communication system, comprising:

a transmitter including a transmission circuit unit configured to generate a radio-frequency signal for transmitting data and an electric-field-coupling antenna configured to transmit the radio-frequency signal as an electrostatic magnetic field;

a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the radio-frequency signal received by the electric-field-coupling antenna; and

a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss,

wherein the surface-wave transmission line includes a plurality of separate dielectrics or magnetic bodies.

2. The communication system according to claim 1 , wherein the radio-frequency signal is an ultra-wideband signal using an ultra-wideband.

3. The communication system according to claim 1 , wherein the surface-wave transmission line includes a dielectric with a dielectric constant ∈ greater than a dielectric constant ∈ 0 of air.

4. The communication system according to claim 3 , wherein the surface-wave transmission line includes a dielectric whose dielectric constant becomes greater toward an inner part thereof.

5. The communication system according to claim 3 , wherein the surface-wave transmission line is embedded in another dielectric with a lower dielectric constant.

6. The communication system according to claim 1 , wherein the surface-wave transmission line includes a magnetic body with a magnetic permeability μ greater than a magnetic permeability 82 0 of air.

7. The communication system according to claim 6 , wherein the surface-wave transmission line includes a magnetic body whose magnetic permeability becomes greater toward an inner part thereof.

8. The communication system according to claim 6 , wherein the surface-wave transmission line is embedded in another magnetic body with a lower magnetic permeability.

9. The communication system according to claim 1 , wherein the receiver rectifies the radio-frequency signal received by the electric-field-coupling antenna and generates electric power.

10. A communication apparatus, comprising:

an apparatus casing;

a communication circuit unit configured to output a radio-frequency signal for transmitting data, the communication circuit unit being accommodated in the apparatus casing;

a resonating section configured to allow the radio-frequency signal output from the communication circuit unit to resonate at a desired frequency, the resonating section being accommodated in the apparatus casing;

a coupling electrode having a central portion connected to the resonating section, the coupling electrode being accommodated in the apparatus casing; and

a surface-wave transmission line disposed in front of the coupling electrode, wherein the surface-wave transmission line captures an electromagnetic field generated in the vicinity of a front side of the coupling electrode and transmits the captured electromagnetic field as a surface wave at an interior of the surface-wave transmission line.

11. The communication apparatus according to claim 10 , wherein the surface-wave transmission line captures a surface wave emanating from the coupling electrode and guides the surface wave to a desired region of a surface of the casing.

12. The communication apparatus according to claim 10 , wherein the resonating section includes a series inductor and a parallel inductor.

13. A communication system, comprising:

a transmitter including a transmission circuit unit configured to generate a radio-frequency signal for transmitting data and an electric-field-coupling antenna configured to transmit the radio-frequency signal as an electrostatic magnetic field;

a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the radio-frequency signal received by the electric-field-coupling antenna; and

a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss,

wherein the surface-wave transmission line includes a dielectric with a dielectric constant ∈ greater than a dielectric constant ∈ 0 of air, and the dielectric ∈ constant becomes greater toward an inner part of the transmission line.

14. A communication system, comprising:

a transmitter including a transmission circuit unit configured to generate a radio-frequency signal for transmitting data and an electric-field-coupling antenna configured to transmit the radio-frequency signal as an electrostatic magnetic field;

a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the radio-frequency signal received by the electric-field-coupling antenna; and

a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss,

wherein the surface-wave transmission line includes a magnetic body with a magnetic permeability μ greater than a magnetic permeability μ 0 of air, and the magnetic permeability μ becomes greater toward an inner part of the magnetic body.