Microstrip to dielectric waveguide transition

• US 4,745,377 A
• Filed: 06/08/1987
• Issued: 05/17/1988
• Est. Priority Date: 06/08/1987
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Babbitt, Richard W., Stern, Richard A.
• Primary Examiner(s): GENSLER, PAUL L
• Application Number:
  US07/059,347
• Time in Patent Office: 344 Days
• Field of Search: 333/21 R, 333/26, 333/34, 333/246, 333/254, 333/260
• US Class Current: 333/26
• CPC Class Codes: H01P 5/087 Transitions to a dielectric waveguide

Abstract

A microstrip to dielectric waveguide transition is provided comprising a gth of rectangular dielectric waveguide which has one end tapered in such a manner that the height of the waveguide top surface above the waveguide bottom surface decreases linearly from full height to zero height at the tapered end of the length of waveguide. The bottom surface of the waveguide length is mounted on the top surface of a planar microstrip dielectric substrate having an electrically conductive metallic ground plane on the bottom substrate surface and a length of microstrip conductor on the top substrate surface aligned with the waveguide length and abutting the tapered end of the waveguide length. A second length of microstrip conductor is mounted on the tapered portion and part of the untapered portion of the top surface of the waveguide length and is electrically connected to the first microstrip conductor at the tapered end of the waveguide length. The dielectric constant of the microstrip substrate should be no greater than the dielectric constant of the dielectric waveguide length and preferably should be much less.

Claims

1. A microstrip to dielectric waveguide transition comprising

a length of microstrip transmission line dielectric substrate having top and bottom parallel surfaces;

first electrically conductive microstrip conductor means mounted on the top surface of said substrate and extending over only a portion of the total length of the substrate so that the remaining portion of said substrate total length is not occupied by said conductor means;

an electrically conductive ground plane mounted on the bottom surface of said substrate;

a length of dielectric waveguide having a rectangular cross-sectional area and top and bottom surfaces mounted on said substrate with the bottom surface of the waveguide abutting the top surface of the substrate, said length of waveguide being aligned with said first microstrip conductor means and being disposed in said remaining portion of said substrate total length so that one end of said waveguide length abuts an end of said first microstrip conductor means, the top surface of said waveguide length being tapered such that the height of the waveguide top surface above the waveguide bottom surface decreases linearly from full height at a first point on said waveguide top surface which is spaced a distance away from said one end of said waveguide length to zero height at said one end of said waveguide length; and

second electrically conductive microstrip conductor means electrically connected to said first microstrip conductor means and mounted on the top surface of said waveguide length, said second microstrip conductor means extending between said one end of said waveguide length and a second point of full waveguide height on said waveguide top surface which is a short distance beyond said first point of full waveguide height.

2. A microstrip to dielectric waveguide transition as claimed in claim 1 wherein

said first electrically conductive microstrip conductor means and said second electrically conductive microstrip conductor means each comprise a separate microstrip conductor, and

said separate microstrip conductors are electrically interconnected at said one end of said length of dielectric waveguide.

3. A microstrip to dielectric waveguide transition as claimed in claim 1 wherein said first electrically conductive microstrip conductor means and said second electrically conductive microstrip conductor means together comprise a single length of microstrip conductor.

4. A microstrip to dielectric waveguide transition as claimed in claim 1 wherein the other end of said length of dielectric waveguide is a short distance beyond said second point of full waveguide height on said waveguide top surface, and

said other end of said length of dielectric waveguide is adapted to be coupled to a second length of dielectric waveguide.

5. A microstrip to dielectric waveguide transition as claimed in claim 1 wherein the dielectric constant of said microstrip transmission line dielectric substrate is no greater than the dielectric constant of said length of dielectric waveguide.

6. A microstrip to dielectric waveguide transition as claimed in claim 1 wherein the dielectric constant of said microstrip transmission line dielectric substrate is much less than the dielectric constant of said length of dielectric waveguide.