Flat Semi-Transparent Ground Plane for Reducing Multipath

• US 20120154241A1
• Filed: 01/18/2011
• Published: 06/21/2012
• Est. Priority Date: 01/22/2010
• Status: Active Grant

• Current Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Original Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Inventors: Tatarnikov, Dmitry, Klionovski, Kirill
• Granted Patent: US 9,048,546 B2
• Time in Patent Office: Days
• US Class Current: 343/848
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective

Abstract

Multipath reception by an antenna is reduced by mounting the antenna on a semi-transparent ground plane that has a controlled distribution of layer impedance over a central region and a peripheral region. The central region includes a continuous conductive segment on which the ground element of the antenna is disposed. The distribution of the layer impedance over the peripheral region is configured by multiple conductive segments electromagnetically coupled by lumped circuit elements. A semi-transparent ground plane can be fabricated by depositing a metal film on a dielectric substrate and etching grooves into the metal film to form a desired pattern of conductive segments. Lumped circuit elements can be fabricated as discrete devices, surface mount devices, and integrated circuit devices. Various semi-transparent ground planes can be configured for linearly-polarized and circularly-polarized radiation.

Claims

1. A ground plane comprising:

an insulating layer, having a surface with an outer perimeter and an inner perimeter, comprising;

a central region consisting of the region of the surface within the inner perimeter; and

a peripheral region consisting of the region of the surface between the inner perimeter and the outer perimeter;

a first conductive segment disposed on the entirety of the central region;

a second conductive segment disposed on a first portion of the peripheral region and in electrical contact with the first conductive segment;

a third conductive segment disposed on a second portion of the peripheral region and spaced apart from the first conductive segment and from the second conductive segment; and

a lumped circuit element electromagnetically coupled to the second conductive segment and to the third conductive segment.

2. The ground plane of claim 1, wherein:

the lumped circuit element is one of a plurality of lumped circuit elements electromagnetically coupled to the second conductive segment and to the third conductive segment.

3. The ground plane of claim 1, wherein the lumped circuit element comprises at least one of a resistor, a capacitor, or an inductor.

4. The ground plane of claim 1, wherein the lumped circuit element is a first lumped circuit element, further comprising:

a fourth conductive segment disposed on a fourth portion of the peripheral region, wherein the fourth conductive segment is;

in electrical contact with the first conductive segment;

spaced apart from the second conductive segment; and

spaced apart from the third conductive segment;

a fifth conductive segment disposed on a fifth portion of the peripheral region and spaced apart from the first conductive segment, from the second conductive segment, from the third conductive segment, and from the fourth conductive segment; and

a second lumped circuit element electromagnetically coupled to the fourth conductive segment and to the fifth conductive segment.

5. The ground plane of claim 4, wherein:

the first lumped circuit element is one of a first plurality of lumped circuit elements electromagnetically coupled to the second conductive segment and to the third conductive segment; and

the second lumped circuit element is one of a second plurality of lumped circuit elements electromagnetically coupled to the fourth conductive segment and to the fifth conductive segment.

6. The ground plane of claim 4, wherein:

the outer perimeter is configured as a first rectangle having a first side and a second side parallel to the first side;

the inner perimeter is disposed between the first side and the second side;

the second conductive segment is configured as a second rectangle and disposed between the inner perimeter and the first side;

the third conductive segment is configured as a third rectangle and disposed between the second conductive segment and the first side;

the fourth conductive segment is configured as a fourth rectangle and disposed between the inner perimeter and the second side; and

the fifth conductive segment is configured as a fifth rectangle and disposed between the fourth conductive segment and the second side.

7. The ground plane of claim 1, wherein:

the outer perimeter is configured as a first circle with a first radius;

the inner perimeter is configured as a second circle with a second radius, wherein the second circle is concentric with the first circle and the second radius is less than the first radius;

the second conductive segment is configured as a first annular ring with an inner radius and an outer radius, wherein the first annular ring is concentric with the first circle and the inner radius of the first annular ring is equal to the second radius and the outer radius of the first annular ring is greater than the inner radius of the first annular ring and less than the first radius; and

the third conductive segment is configured as a second annular ring with an inner radius and an outer radius, wherein the second annular ring is concentric with the first circle and the inner radius of the second annular ring is greater than the outer radius of the first annular ring and the outer radius of the second annular ring is greater than the inner radius of the second annular ring and less than or equal to the first radius.

8. The ground plane of claim 1, wherein:

the insulating layer comprises a dielectric substrate;

the first conductive segment comprises a first metal film;

the second conductive segment comprises a second metal film; and

the third conductive segment comprises a third metal film.

9. A ground plane comprising:

an insulating layer having an outer perimeter;

a conductive layer disposed on the insulating layer, wherein the conductive layer has an outer perimeter coincident with the outer perimeter of the insulating layer, comprising;

a central region consisting of the region of the conductive layer within an inner perimeter; and

a peripheral region consisting of the region of the conductive layer between the inner perimeter and the outer perimeter;

a groove in the conductive layer, wherein the groove;

has a depth equal to the thickness of the conductive layer;

has a first end point at a first locus on the outer perimeter, a first locus on the inner perimeter, or a first locus within the peripheral region; and

has a second end point at a second locus on the outer perimeter, a second locus on the inner perimeter, or a second locus within the peripheral region; and

a lumped circuit element electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the opposite side of the groove.

10. The ground plane of claim 9, wherein:

the lumped circuit element is one of a plurality of lumped circuit elements electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the opposite side of the groove.

11. The ground plane of claim 9, wherein the lumped circuit element comprises at least one of a resistor, a capacitor, or an inductor.

12. The ground plane of claim 9, wherein the groove is one of a plurality of grooves.

13. The ground plane of claim 12, further comprising:

for each groove in the plurality of grooves, at least one lumped circuit element electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the other side of the groove.

14. The ground plane of claim 12, wherein the plurality of grooves is configured as a geometrical array of grooves.

15. The ground plane of claim 14, wherein the geometrical array comprises one of:

a geometrical array of rectangles;

a geometrical array of rhombuses;

a geometrical array of triangles;

or

a geometrical array of hexagons.

16. The ground plane of claim 9, wherein:

the insulating layer comprises a dielectric substrate; and

the conductive layer comprises a metal film.

17. An antenna system comprising:

an antenna comprising;

a radiator element; and

a ground element; and

a ground plane comprising;

an insulating layer, having a surface with an outer perimeter and an inner perimeter, comprising;

a central region consisting of the region of the surface within the inner perimeter; and

a peripheral region consisting of the region of the surface between the inner perimeter and the outer perimeter;

a first conductive segment disposed on the entirety of the central region;

a second conductive segment disposed on a first portion of the peripheral region and in electrical contact with the first conductive segment;

a third conductive segment disposed on a second portion of the peripheral region and spaced apart from the first conductive segment and from the second conductive segment; and

a lumped circuit element electromagnetically coupled to the second conductive segment and to the third conductive segment;

wherein the ground element is disposed on the central region.

18. The antenna system of claim 17, wherein:

the lumped circuit element is one of a plurality of lumped circuit elements electromagnetically coupled to the second conductive segment and to the third conductive segment.

19. The antenna system of claim 17, wherein the lumped circuit element comprises at least one of a resistor, a capacitor, or an inductor.

20. The antenna system of claim 17, wherein:

the insulating layer comprises a dielectric substrate;

the first conductive segment comprises a first metal film;

the second conductive segment comprises a second metal film; and

the third conductive segment comprises a third metal film.

21. The antenna system of claim 17, wherein the lumped circuit element is a first lumped circuit element and the ground plane further comprises:

a fourth conductive segment disposed on a fourth portion of the peripheral region, wherein the fourth conductive segment is;

in electrical contact with the first conductive segment;

spaced apart from the second conductive segment; and

spaced apart from the third conductive segment;

a fifth conductive segment disposed on a fifth portion of the peripheral region and spaced apart from the first conductive segment, from the second conductive segment, from the third conductive segment, and from the fourth conductive segment; and

a second lumped circuit element electromagnetically coupled to the fourth conductive segment and to the fifth conductive segment.

22. The antenna system of claim 21, wherein:

the first lumped circuit element is one of a first plurality of lumped circuit elements electromagnetically coupled to the second conductive segment and to the third conductive segment; and

the second lumped circuit element is one of a second plurality of lumped circuit elements electromagnetically coupled to the fourth conductive segment and to the fifth conductive segment.

23. An antenna system comprising:

an antenna comprising;

a radiator element; and

a ground element; and

a ground plane comprising;

an insulating layer having an outer perimeter;

a conductive layer disposed on the insulating layer, wherein the conductive layer has an outer perimeter coincident with the outer perimeter of the insulating layer, comprising;

a central region consisting of the region of the conductive layer within an inner perimeter; and

a peripheral region consisting of the region of the conductive layer between the inner perimeter and the outer perimeter;

a groove in the conductive layer, wherein the groove;

has a depth equal to the thickness of the conductive layer;

has a first end point at a first locus on the outer perimeter, a first locus on the inner perimeter, or a first locus within the peripheral region; and

has a second end point at a second locus on the outer perimeter, a second locus on the inner perimeter, or a second locus within the peripheral region; and

a lumped circuit element electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the opposite side of the groove;

wherein the ground element is disposed on the central region.

24. The antenna system of claim 23, wherein:

the lumped circuit element is one of a plurality of lumped circuit elements electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the opposite side of the groove.

25. The antenna system of claim 23, wherein the lumped circuit element comprises at least one of a resistor, a capacitor, or an inductor.

26. The antenna system of claim 23, wherein the groove is one of a plurality of grooves.

27. The antenna system of claim 26, wherein the ground plane further comprises:

for each groove in the plurality of grooves, at least one lumped circuit element electromagnetically coupled to a portion of the conductive layer on one side of the groove to a portion of the conductive layer on the other side of the groove.

28. The antenna system of claim 26, wherein the plurality of grooves is configured as a geometrical array of grooves.

29. The antenna system of claim 23, wherein:

the insulating layer comprises a dielectric substrate; and

the conductive layer comprises a metal film.