Enhanced guided surface waveguide probe

1. A guided surface waveguide probe, comprising:

a charge terminal elevated over a lossy conducting medium, the charge terminal comprising a upper terminal portion coupled to a lower terminal portion through a variable capacitance; and

a feed network that couples an excitation source to the charge terminal and provides a voltage to the charge terminal with a phase delay (Φ) that matches a wave tilt angle (Ψ) of a Zenneck surface wave generated by the guided surface wave probe, the wave tilt angle (Ψ) being associated with a complex Brewster angle of incidence (θ i,B ) associated with the lossy conducting medium.

2. The guided surface waveguide probe of claim 1 , wherein the feed network comprises a feed line conductor coupled to the charge terminal and a coil coupled between the lossy conducting medium and the feed line conductor, where the phase delay (Φ) of the feed network includes a phase delay (θ y ) associated with the feed line conductor and a phase delay (θ c ) associated with the coil.

3. The guided surface waveguide probe of claim 2 , wherein the coil is a helical coil.

4. The guided surface waveguide probe of claim 2 , wherein the charge terminal is coupled to the coil via a tap connection.

5. The guided surface waveguide probe of claim 1 , wherein the feed network is configured to vary the phase delay (Φ) to match the wave tilt angle (Ψ).

6. The guided surface waveguide probe of claim 1 , comprising a probe control system configured to adjust the feed network based at least in part upon characteristics of the lossy conducting medium.

7. The guided surface waveguide probe of claim 6 , wherein the probe control system adjusts the phase delay (Φ) of the feed network to match a modified wave tilt angle in response to changed characteristics of the lossy conducting medium, the modified wave tilt angle corresponding to a complex Brewster angle of incidence associated with the lossy conducting medium having the changed characteristics.

8. The guided surface waveguide probe of claim 1 , wherein the variable capacitance of the charge terminal is adjusted based upon an image ground plane impedance (Z in ) associated with the lossy conducting medium.

9. A method, comprising:

positioning a charge terminal at a defined height over a lossy conducting medium, where the charge terminal comprises a upper terminal portion coupled to a lower terminal portion through a variable capacitance; and

adjusting a phase delay (Φ) of a feed network to match a wave tilt angle (Ψ) of a Zenneck surface wave generated by the charge terminal, the wave tilt angle (Ψ) being associated with a complex Brewster angle of incidence (θ i,B ) associated with the lossy conducting medium, where the feed network is configured to couple an excitation source to the charge terminal and provide a voltage to the charge terminal with the phase delay (Φ).

10. The method of claim 9 , wherein the lossy conducting medium is a terrestrial medium.

11. The method of claim 9 , wherein the feed network comprises a feed line conductor coupled to the charge terminal and a coil coupled between the lossy conducting medium and the feed line conductor, where the phase delay (Φ) of the feed network includes a phase delay (θ y ) associated with the feed line conductor and a phase delay (θ c ) associated with the coil.

12. The method of claim 9 , wherein the complex Brewster angle of incidence (θ i,B ) associated with the lossy conducting medium is based upon an operational frequency of the voltage and characteristics of the lossy conducting medium.

13. The method of claim 12 , wherein the characteristics of the lossy conducting medium include conductivity and permittivity.

14. The method of claim 9 , further comprising adjusting the variable capacitance of the charge terminal based upon an image ground plane impedance (Z in ) associated with the lossy conducting medium.

15. The method of claim 14 , wherein the variable capacitance of the charge terminal is adjusted based upon a reactive component of the image ground plane impedance (Z in ).

16. The method of claim 15 , wherein the variable capacitance of the charge terminal is adjusted to match the reactive component of the image ground plane impedance (Z in ) with a structure impedance (Z base ) associated with the feed network and the charge terminal.

17. The method of claim 14 , wherein the image ground plane impedance (Z in ) is based at least in part upon a phase shift (θ d ) between a physical boundary of the lossy conducting medium and a conducting image ground plane.

18. The method of claim 17 , wherein the physical boundary of the lossy conducting medium and the conducting image ground plane are separated by a complex depth.

19. The method of claim 14 , further comprising:

sensing a changed characteristic of the lossy conducting medium;

adjusting the phase delay (Φ) of the feed network connected to the charge terminal to match a modified wave tilt angle in response to the changed characteristic of the lossy conducting medium, the modified wave tilt angle corresponding to a complex Brewster angle of incidence associated with the lossy conducting medium having the changed characteristic; and

adjusting the variable capacitance of the charge terminal based upon a new image ground plane impedance that is based upon the lossy conducting medium having the changed characteristic.

20. The method of claim 14 , wherein the phase delay (Φ) of the feed network is fixed while the variable capacitance of the charge terminal is adjusted.