Broadband circular polarization antenna

• US 5,382,959 A
• Filed: 04/10/1992
• Issued: 01/17/1995
• Est. Priority Date: 04/05/1991
• Status: Expired due to Fees

• Current Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Original Assignee: Ball Corporation
• Inventors: Sreenivas, Ajay I., Olson, Steven C., Pett, Todd A.
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): LE, HOANGANH T
• Application Number:
  US07/866,868
• Time in Patent Office: 1,012 Days
• Field of Search: 343/700 MS, 343/829, 343/833, 343/834, 343/835, 343/846, 343/848, 343/847, 343/853
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001

Abstract

An efficient, lightweight, broadband antenna, having high quality circular polarization capabilities, is disclosed for use in a variety of applications. In one embodiment, signals are fed to, or received by, an array of electromagnetically coupled patch pairs arranged in sequential rotation by an interconnect network which is coplanar with the coupling patches of the patch pairs. The interconnect network includes phase transmission line means, the lengths of which are preselected to provide the desired phase shifting among the coupling patches. The complexity of the array and the space required are thus reduced. In one described embodiment, two such arrays are employed, each having four patch pairs. The two arrays are arranged in sequential rotation to provide normalization of the circularly polarized transmitted or received beam. In another embodiment, a lightweight material having a dielectric constant less than about 1.5 is employed in the lower resonant cavity and, preferably, in the upper resonant cavity as well.

Claims

1. A multi-layer microstrip antenna comprising:

a plurality of stacks of resonantly-dimensioned radiator patches, each stack including a plurality of electromagnetically coupled radiator patches which are formed on corresponding dielectric substrates and stacked above one another with interleaved dielectric spacing material over an electrically conductive ground surface, said dielectric spacing material having a dielectric constant of approximately 1; and

a dielectric layer having a relative dielectric constant of approximately 1 being disposed between said ground surface and the lowermost of said radiator patches, wherein the thickness of the dielectric layer is at least approximately ten times greater than the thickness of the adjacent, overlying dielectric substrate, and wherein the effective relative dielectric constant of the resonant cavities underlying all of said patches is approximately 1;

a microstrip RF feed network formed on a dielectric substrate which also carries said lowermost of said radiator patches;

wherein said patches are of approximately square resonant dimensions and wherein said microstrip RF feed network emanates from a coaxial feed pin through impedance matching and phase-shifting microstrip feedlines to plural feed points on said lowermost of said radiator patches to achieve approximately circular polarization of RF signals radiating to/from said patches.

2. A multi-layer microstrip antenna as in claim 1 having a plurality of such stacks of radiators arrayed equidistantly around a predetermined closed locus.

3. A multi-layer microstrip antenna as in claim 1 wherein the thickness of each layer of said dielectric spacing material is at least approximately ten times greater than the thickness of the respectively associated, overlying dielectric substrate.

4. A multi-layer microstrip antenna comprising an array of microstrip multi-layer radiator stacks, wherein each of said stacks includes:

a parasitically driven resonant radiator patch that is disposed on a first dielectric support layer and stacked above a directly driven microstrip radiator patch that is disposed on a second dielectric support layer, with first dielectric spacing material therebetween, said second dielectric support layer overlying a ground plane with a second dielectric spacing material therebetween, the thickness of the second dielectric spacing material being at least approximately ten times greater than the second dielectric support layer; and

wherein the dielectrically loaded resonant cavity underlying said directly driven radiator patch has an effective relative dielectric constant which is approximately equal to one.

5. A multi-layer microstrip antenna as in claim 4, the thickness of said first dielectric spacing material being at least approximately ten times greater than the thickness of the first dielectric support layer, and wherein the effective relative dielectric constant of the resonant cavity underlying the parasitically driven radiator patch is approximately one.