Superposition of guided surface waves on lossy media

Abstract

Disclosed are various embodiments for superposition of guided surface wave launched along the surface of a lossy medium. In one example, a field pattern of Zenneck surface waves is launched along a surface of a lossy conducting medium by excitation phasing of the array of guided surface waveguide probes. The Zenneck surface waves are launched based on resultant fields that synthesize a wave front incident at a complex Brewster angle of incidence (θi,B) associated with the lossy conducting medium.

Therefore, the following is claimed: 
     
         1 . A method, comprising:
 controlling a field pattern of Zenneck surface waves launched along a surface of a lossy conducting medium by excitation phasing of an array of guided surface waveguide probes; and   generating, by the array of guided surface waveguide probes, resultant fields that are substantially mode-matched to a guided surface wave mode based on a complex Brewster angle of incidence (θ i,B ) associated with the lossy conducting medium to launch the Zenneck surface waves.   
     
     
         2 . The method of  claim 1 , wherein the array of guided surface waveguide probes are positioned at predefined distances in a geometric pattern to produce at least one transmission lobes of the field pattern of Zenneck surface waves. 
     
     
         3 . The method of  claim 2 , wherein the geometric pattern is at least one of a line pattern, a triangle pattern, a square pattern, a rectangular pattern, or a circular pattern. 
     
     
         4 . The method of  claim 1 , wherein interference of the resultant fields causes the predefined field pattern. 
     
     
         5 . The method of  claim 1 , further comprising:
 controlling the field pattern to provide a null area where the Zenneck surface waves are unreceivable.   
     
     
         6 . The method of  claim 1 , wherein the excitation phasing comprises supplying a corresponding excitation phase delay for individual ones of the array of guided surface waveguide probes. 
     
     
         7 . The method of  claim 6 , wherein the corresponding excitation phase delay is provided using delay circuitry between an excitation source and individual ones of the array of guided surface waveguide probes. 
     
     
         8 . The method of  claim 1 , wherein a position of a variable tap on a coil is varied to control the excitation phase delay. 
     
     
         9 . The method of  claim 1 , further comprising:
 receiving a field strength from a field meter; and   adjusting operation of the array of guided surface waveguide probes based on the field strength to maintain the field pattern.   
     
     
         10 . The method of  claim 1 , further comprising:
 adjusting individual ones of a plurality of excitation sources to provide a corresponding excitation phase delay for individual ones of the array of guided surface waveguide probes.   
     
     
         11 . An apparatus, comprising:
 an array of guided surface waveguide probes that generate a field pattern of Zenneck surface waves launched along a surface of a lossy conducting medium by excitation phasing of the array of guided surface waveguide probes, the Zenneck surface waves being launched based on resultant fields that synthesize a wave front incident at a complex Brewster angle of incidence (θ i,B ) associated with the lossy conducting medium.   
     
     
         12 . The apparatus of  claim 11 , further comprising an array control system configured to control operation of individual ones of the guided surface waveguide probes of the array of guided surface waveguide probes. 
     
     
         13 . The apparatus of  claim 11 , wherein the array comprises a first guided surface waveguide probe and a second guided surface waveguide probe separated by a fraction of a wavelength of an excitation frequency of the first and second guided surface waveguide probes, where the second guided surface waveguide probe is excited through a feed network comprising probe delay circuitry configured to delay excitation of the second guided surface waveguide probe by an excitation phase difference. 
     
     
         14 . The apparatus of  claim 11 , further comprising:
 delay circuitry for individual ones of the array of guided surface waveguide probes, wherein the delay circuitry provides an excitation delay between an excitation source and the individual ones of the array of guided surface waveguide probes.   
     
     
         15 . The apparatus of  claim 11 , wherein the array of guided surface waveguide probes are positioned in a geometric pattern. 
     
     
         16 . The apparatus of  claim 15 , the geometric pattern is at least one of a line pattern, a triangle pattern, a square pattern, a rectangular pattern, or a circular pattern. 
     
     
         17 . The apparatus of  claim 11 , further comprising:
 a variable tap on a coil for individual ones of the array of guided surface waveguide probes.   
     
     
         18 . The apparatus of  claim 11 , further comprising:
 at least one field meter, wherein operation of the array of guided surface waveguide probes is adjusted based on a field strength measured by the at least one field meter.   
     
     
         19 . The apparatus of  claim 18 , wherein the at least one field meter is positioned beyond the Hankel crossover distance (R x ) from at least one of the array of guided surface waveguide probes. 
     
     
         20 . The apparatus of  claim 11 , further comprising:
 a plurality of excitation sources, wherein the plurality of excitation sources are adjusted to provide a corresponding excitation phase delay for individual ones of the array of guided surface waveguide probes to generate the field pattern.