Waveguide for the transmission of electromagnetic energy

• US 4,216,449 A
• Filed: 01/12/1978
• Issued: 08/05/1980
• Est. Priority Date: 02/11/1977
• Status: Expired due to Term

• Current Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Original Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Inventors: Kach, Alfred
• Primary Examiner(s): Gensler, Paul L.
• Application Number:
  US05/868,840
• Time in Patent Office: 936 Days
• Field of Search: 333/84 R, 333/95 R, 333/95 S, 333/96, 333/236, 333/239, 333/240, 333/242, 333/243
• US Class Current: 333/236
• CPC Class Codes: H01P 3/16 Dielectric waveguides, i.e. without a longitudinal conductor

Abstract

A waveguide for the transmission of electromagnetic energy which has a low attenuation even with a small line cross-section realized by disposing in the interior of an electromagnetically shielded hollow cylinder, consisting of a substance having a low permittivity, a dielectric wire of a substance having a high permittivity. An E_om -wave (m = 1, 2, 3 . . . , circular H field) is excited in the dielectric wire and the dimensioning of the dielectric wire is such, depending on the permittivities of the two substances and the particular operating frequency, that a TEM wave develops at least substantially in the space in the dielectric hollow cylinder. In the simplest case, the electromagnetic shield can consist of a metal tube and the dielectric hollow cylinder can consist primarily of air. Furthermore, the E_om wave excited in the dielectric wire is preferably the E₀₁ wave (TM₀₁ mode).

Claims

1. A waveguide for the transmission of electromagnetic energy, comprising:

a cylindrical metallic sheath functioning to guide forward electromagnetic waves;

a wire-shaped body disposed coaxially in the interior of said sheath, said sheath and said wire-shaped body defining an intermediate space therebetween;

a medium having a low dielectric constant (ε

₂) located in the space between said sheath and the wire-like body;

said wire-shaped body consisting solely of a dielectric material exhibiting a high dielectric constant (ε

₁) such that an E_om wave (circular H field) can be excited only in the dielectric wire-shaped body, the dimensioning of the dielectric wire-shaped body being such, depending on the dielectric constants ε

₂ and ε

₁, and the particular operating frequency, so that a substantially pure TEM wave can develop at least substantially in the intermediate space.

2. The waveguide as claimed in claim 1, wherein the E_om wave excited in the dielectric wire is an E₀₁ wave (TM₀₁ mode).

3. The waveguide as claimed in claim 1, wherein the permeability μ

₂ of the medium and the permeability μ

₁ of the dielectric wire-shaped body are equal to the vacuum permeability μ

₀, and the dielectric constant ε

₂ of the medium is at least substantially equal to the vacuum dielectric constant ε

₀, while the dielectric constant ε

₁ of the dielectric wire-shaped body is considerably higher.

4. The waveguide as claimed in claim 1, wherein the medium in the space between said sheath and said wire-shaped body is predominantly air.

5. The waveguide as claimed in claim 1, wherein the metallic sheath is a circular cylindrical metal tube.

6. The waveguide as claimed in claim 1, wherein the metallic sheath consists of a cylindrical metallic wire gauze.

7. The waveguide as claimed in claim 1, wherein the wire-shaped body has at least a substantially circular cross-section.

8. The waveguide as claimed in claim 1, wherein the dielectric wire-shaped body is disposed concentrically in the interior of the metallic sheath.

9. The waveguide as claimed in claim 1, wherein the dielectric wire-shaped body comprises a plastic material.

10. The waveguide as claimed in claim 1, wherein the dielectric wire-shaped body consists of a ceramic material.

11. The waveguide as claimed in claim 1, wherein the dielectric wire-shaped body consists of a glass wire.

12. The waveguide as claimed in claim 1, wherein the dielectric wire-shaped body comprises a liquid.

13. The waveguide as claimed in claim 12, said wire-shaped body further comprising:

a flexible tube filled with said liquid.