CIRCULARLY POLARIZED CONNECTED-SLOT ANTENNA

• US 20160190704A1
• Filed: 12/31/2014
• Published: 06/30/2016
• Est. Priority Date: 12/31/2014
• Status: Active Grant

• Current Assignee: Trimble Inc.
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Celik, Nuri
• Granted Patent: US 9,590,314 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave
• CPC Class Codes: H01Q 9/0435 using two feed points
• CPC Class Codes: H01Q 9/0464 Annular ring patch

Abstract

A connected-slot antenna includes a dielectric substrate, a circular patch overlying the dielectric substrate, and a first conductive ring surrounding the circular patch and overlying the dielectric substrate. The first conductive ring is isolated from the circular patch by a first connected slot. At least four feeds are coupled to the circular patch. Each of the at least four feeds are spaced from adjacent ones of the at least four feeds by approximately equal angular intervals. A metamaterial ground plane includes a plurality of conductive patches and a ground plane. The plurality of conductive patches are separated from the circular patch and the first conductive ring by at least the dielectric substrate. The ground plane is electrically coupled to at least a first portion of the plurality of conductive patches. One or more of the plurality of conductive patches and the ground plane are coupled to ground.

Claims

1. A circularly polarized connected-slot antenna configured to receive radiation at global navigation satellite system (GNSS) frequencies, comprising:

a dielectric substrate;

a circular patch overlying the dielectric substrate;

a first conductive ring surrounding the circular patch and overlying the dielectric substrate, the first conductive ring separated from the circular patch by a first connected slot;

at least four impedance transformers overlying the dielectric substrate, each of the at least four impedance transformers including a microstrip and a ground pad that are separated by a first dielectric, each microstrip coupled to a first feed from a coaxial cable at an input and coupled to the circular patch at an output, and each ground pad coupled to a ground from the coaxial cable and coupled to the first conductive ring, wherein the output associated with each microstrip is spaced from adjacent outputs associated with other microstrips by approximately equal angular intervals; and

a metamaterial ground plane comprising;

a plurality of conductive patches arranged along a first plane and separated from the circular patch, the first conductive ring, and the at least four impedance transformers by at least the dielectric substrate, each conductive patch separated from others of the conductive patches;

a ground plane arranged along a second plane, the ground plane electrically coupled to at least a first portion of the plurality of conductive patches; and

a conductive fence extending at least from the first plane to the second plane and extending around a perimeter of the plurality of conductive patches and around a perimeter of the ground plane, wherein one or more of the plurality of conductive patches, the ground plane, and the conductive fence are coupled to ground.

2. The circularly polarized connected-slot antenna of claim 1 wherein the circular patch and the first conductive ring each having a substantially circular shape.

3. The circularly polarized connected-slot antenna of claim 1 further comprising:

a second conductive ring surrounding the first conductive ring and overlying the dielectric substrate, the second conductive ring separated from the first conductive ring by a second connected slot; and

a plurality of second feeds coupled to the second conductive ring, each of the plurality of second feeds spaced from adjacent ones of the plurality of second feeds by approximately equal angular intervals.

4. The circularly polarized connected-slot antenna of claim 1 wherein each microstrip includes at least two conductive traces, a first one of the at least two conductive traces having one end connected to the first feed and another end connected to the output of the microstrip, a second one of the at least two conductive traces having one end connected to the first feed and another end free from connection with a conductor, the first conductive trace and the second conductive trace extending substantially parallel to but separate from each other along multiple sections of the microstrip, each section of the microstrip extending substantially perpendicular to an adjacent section of the microstrip.

5. The circularly polarized connected-slot antenna of claim 1 wherein the ground plane is electrically isolated from at least a second portion of the plurality of conductive patches.

6. The circularly polarized connected-slot antenna of claim 1 wherein the circular patch, the first conductive ring, and the at least four impedance transformers overly a top side of the dielectric substrate, and the plurality of conductive patches are disposed on a backside of the dielectric substrate.

7. The circularly polarized connected-slot antenna of claim 1 wherein the circular patch includes at least four elongated sections extending radially outward from the circular patch and spaced at approximately equal angular intervals around the circular patch, each of the at least four elongated sections coupled to a microstrip at the output of the microstrip, and each microstrip disposed outward beyond an end of an associated one of the at least four elongated sections.

8. The circularly polarized connected-slot antenna of claim 1 further comprising a second dielectric disposed between the plurality of conductive patches and the ground plane.

9. The circularly polarized connected-slot antenna of claim 1 wherein the first dielectric comprises a dielectric disc, and the conductive patch and each microstrip overly the dielectric disc.

10. The circularly polarized connected-slot antenna of claim 1 wherein the first dielectric comprises multiple dielectric plates, and each microstrip is separated from an associated ground pad by one of the multiple dielectric plates.

11. The circularly polarized connected-slot antenna of claim 1 wherein a major surface of the conductive fence extends substantially perpendicular to the first plane and the second plane.

12. The circularly polarized connected-slot antenna of claim 1 wherein the dielectric substrate and the ground plane are circular shaped, and the conductive fence extends around perimeters of the dielectric substrate and the ground plane.

13. A connected-slot antenna, comprising:

a dielectric substrate;

a circular patch overlying the dielectric substrate;

a first conductive ring surrounding the circular patch and overlying the dielectric substrate, the first conductive ring coupled to ground and isolated from the circular patch by a first connected slot;

at least four feeds coupled to the circular patch, each of the at least four feeds spaced from adjacent ones of the at least four feeds by approximately equal angular intervals;

a metamaterial ground plane comprising;

a plurality of conductive patches arranged along a first plane and separated from the circular patch and the first conductive ring by at least the dielectric substrate; and

a ground plane arranged along a second plane, the ground plane electrically coupled to at least a first portion of the plurality of conductive patches, wherein one or more of the plurality of conductive patches and the ground plane are coupled to ground.

14. The connected-slot antenna of claim 13 further comprising at least four impedance transformers overlying the dielectric substrate, each of the at least four impedance transformers including a microstrip and a ground pad that are separated by a first dielectric, each microstrip coupled to one of the at least four feeds, and each ground pad coupled to ground.

15. The connected-slot antenna of claim 13 further comprising a conductive fence extending at least from the first plane to the second plane and extending around a perimeter of the plurality of conductive patches and around a perimeter of the ground plane.

16. The connected-slot antenna of claim 13 wherein the circular patch is electrically coupled to at least one of the plurality of conductive patches and to the ground plane by a via.

17. The connected-slot antenna of claim 13 further comprising:

a second conductive ring surrounding the first conductive ring and overlying the dielectric substrate, the second conductive ring isolated from the first conductive ring by a second connected slot; and

a plurality of second feeds coupled to the second conductive ring, each of the plurality of second feeds spaced from adjacent ones of the plurality of second feeds by approximately equal angular intervals.

18. An antenna configured to receive radiation at global navigation satellite system (GNSS) frequencies, comprising:

a dielectric substrate;

a circular patch overlying the dielectric substrate;

a first conductive ring surrounding the circular patch and overlying the dielectric substrate;

a first connected slot extending between the circular patch and the first conductive ring and separating the circular patch from the first conductive ring;

at least four impedance transformers overlying the dielectric substrate, each of the at least four impedance transformers coupled to a first input feed and coupled to the circular patch at an output, each output separated from adjacent outputs by approximately equal angular intervals; and

a metamaterial ground plane comprising;

a plurality of conductive patches arranged along a first plane and separated from the circular patch, the first conductive ring, and the at least four impedance transformers by at least the dielectric substrate; and

a ground plane arranged along a second plane, the ground plane electrically coupled to at least a first portion of the plurality of conductive patches, wherein one or more of the plurality of conductive patches and the ground plane are coupled to ground.

19. The antenna of claim 18 further comprising a conductive fence extending at least from the first plane to the second plane and extending around a perimeter of the plurality of conductive patches and around a perimeter of the ground plane.

20. The antenna of claim 18 further comprising:

a second conductive ring surrounding the first conductive ring and overlying the dielectric substrate, the second conductive ring isolated from the first conductive ring by a second connected slot; and

a plurality of second input feeds disposed in the second connected slot and coupled to the second conductive ring, each of the plurality of second input feeds separated from adjacent ones of the second input feeds by approximately equal angular intervals.