HYBRID MODE ELECTRIC TRANSMISSION LINE USING ACCENTUATED ASYMMETRICAL DUAL SURFACE WAVES

• US 3,668,574 A
• Filed: 04/17/1970
• Issued: 06/06/1972
• Est. Priority Date: 10/07/1966
• Status: Expired due to Term

• Current Assignee: Harold Monteagle Barlow
• Original Assignee: Harold Monteagle Barlow
• Inventors: Barlow, Harold Monteagle
• Primary Examiner(s): Saalbach, Herman Karl
• Assistant Examiner(s): Punter, Wm. H.
• Application Number:
  US05/029,626
• Time in Patent Office: 781 Days
• Field of Search: 333/84R,95S,96 174/12C 156/53
• US Class Current: 333/240
• CPC Class Codes: H01B 11/14 Continuously inductively loaded cables, e.g. Krarup cables
• CPC Class Codes: H01B 11/1895 Particular features or applications
• CPC Class Codes: H01P 3/02 with two longitudinal conductors
• CPC Class Codes: H01P 3/04 Lines formed as Lecher wire pairs

Abstract

A method and means for reducing net transmission losses and frequency dispersion within an electrical transmission line having dual conducting surfaces and carrying a hybrid mode electromagnetic wave comprising both a TEM component and a dual surface wave component. One of the two conducting surfaces is caused to have more surface resistance than the other by a predetermined amount thereby making the surface wave part of the field asymmetric and enhancing the energy particularly associated with the surface wave to the detriment of the other existing components such as the TEM field. The predetermined amount of surface reactance is controlled to reduce the product of transverse attenuation and phase-change coefficients for the hybrid wave thereby causing a reduction in its overall axial attenuation coefficient in the direction of propogation. Thus the wave is slowed down by the dielectric loading, its phase-change coefficient is increased and made more nearly proportional directly to frequency.

Claims

1. In a hybrid mode dual surface electrical transmission line, a new use for dielectric material on one conducting surface of said line which is of the type that inherently transmits a hybrid wave comprising at least a TEM mode and a dual surface wave mode and which has a pair of spaced-apart generally parallel conducting surfaces with a second dielectric material in between, said new use comprising the method steps of:

adding to said one conducting surface a predetermined thickness of the first-mentioned dielectric material having a permittivity greater than said second dielectric material to increase the surface reactance of said one surface and to product an accentuated asymmetrical dual surface wave mode thereby reducing the dispersion and attenuation of the resulting hybrid mode while simultaneously introducing additional line losses caused by the addition of said first dielectric material, and controlling the predetermined thickness of said first dielectric material to produce a substantially constant phase velocity over a relatively wide frequency range and to produce an increase in overall line attenuation due to said additional losses that is significantly less than an accompanying reduction in overall line attenuation due to said accentuated asymmetrical dual surface wave whereby a net reduction in overall line attenuation is attained.

2. A new use method as in claim 1, wherein said thickness controlling step causes the net line attenuation and dispersion to be minimized.

3. A method for decreasing frequency dispersion and net line attenuation in a two conductor transmission line system comprising a pair of spaced-apart generally parallel conducting surfaces having a dielectric medium disposed between said surfaces wherein a hybrid wave inherently exists having both TEM and dual surface wave components, said method comprising the step of introducing a predetermined thickness of a further dielectric medium along the length of one of said conducting surface, said predetermined thickness and the relative permittivity of said further dielectric material being chosen to enhance the dual surface wave component relative to the TEM component and to make said dual surface wave component asymmetric whereby the frequency dispersion and net line attenuation of the overall hybrid mode are decreased in spiTe of added losses introduced by the addition of said further dielectric medium.