Laterally isolated microstrip antenna

• US 4,460,894 A
• Filed: 03/21/1983
• Issued: 07/17/1984
• Est. Priority Date: 08/11/1982
• Status: Expired due to Term

• Current Assignee: Sensor Systems
• Original Assignee: Sensor Systems
• Inventors: Robin, Seymour, Klein, Yosef
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US06/477,214
• Time in Patent Office: 484 Days
• Field of Search: 343/700 MS, 343/785, 343/795, 343/841
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

A microstrip antenna which includes a ground member, a dielectric element mounted on the ground member and a radiating element on the dielectric element, has been improved by means of a distinct grounding ring of conductive material which is spaced apart from and extends around the radiating element. The grounding ring is connected to a ground member, thereby laterally isolating the antenna and permitting a closer spacing with adjacent antennas. The gap between the radiating element and the grounding ring is different in different directions.

Claims

1. An improved microstrip antenna for being mounted generally in a plane in which another antenna is mounted, the first mentioned microstrip antenna comprising a ground member, a dielectric element on the ground member and a generally planar radiating element on the dielectric element for radiating a signal at a radiating frequency, grounding ring means of conductive material spaced from and extending at least partially around the radiating element, and means electrically connecting the ring means to the ground member for limiting lateral radiation from the radiating element in the plane of the radiating element, the improvement comprising the provision of:

the space between the radiating element and the grounding ring means being less in a first direction toward the other antenna than the space between the radiating element and the grounding ring means in a direction at a right angle the first direction.

2. The microstrip antenna of claim 1 wherein the distance between the radiating element and the grounding ring means in a direction opposite the direction toward the other antenna being at least eleven percent of the wavelength of the electromagnetic radiation radiating from the radiating element at the operating frequency.

3. The microstrip antenna of claim 2 wherein the width of the grounding ring means is less than the distance between the radiating element and the grounding ring means.

4. The microstrip antenna of claim 3 wherein the width of the grounding ring means is less than 1/4 inch.

5. The microstrip antenna of claim 1 wherein the distance between the radiating element and the grounding ring means in a direction opposite the direction toward the other antenna is about fourteen percent of the wavelength of the electromagnetic radiation radiating from the radiating element at the operating frequency.

6. The microstrip antenna of claim 1, wherein the grounding ring means is in the same plane as the radiating element.

7. The microstrip antenna of claim 1, wherein the grounding ring means extends entirely around the radiating element.

8. The microstrip antenna of claim 1, wherein the improvement further comprises the provision of a plurality of spaced grounding elements extending through the dielectric and connecting the grounding ring means to the ground member.

9. The microstrip antenna of claim 8, wherein the grounding elements are mutually spaced along the grounding ring means by a distance of no more than approximately one-half wavelength at the operating frequency of the microstrip antenna.

10. A microstrip antenna assembly comprising:

a pair of microstrip antennas, each antenna comprising a ground member, a dielectric element on the ground member and a generally planar readiating element on the dielectric element for radiating a signal at a radiating frequency, the antennas being mutually spaced from each other and generally in the same plane, the improvement comprising;

separate planar grounding rings, each laterally spaced from and extending at least partially around each of the antennas, each grounding ring being a plane parallel to the plane of the radiating element of the antenna, and means connecting each of the grounding rings to their respective ground members to isolate laterally the antennas from each other.

11. The microstrip antenna assembly of claim 10, each grounding ring being continuous and extending entirely around its respective antenna.

12. The microstrip antenna assembly of claim 10, wherein the improvement further comprises the provision of a plurality of spaced grounding elements extending through the dielectrics of each antenna and connecting each grounding ring to its respective ground member.

13. The microstrip antenna assembly of claim 10, the antennas being spaced approximately 16 inches apart from each other.

14. An improved microstrip antenna for being mounted in a plane in which another antenna is mounted, the first mentioned microstrip antenna comprising a ground member, a dielectric element on the ground member and a generally planar radiating element on the dielectric element for radiating a signal at a radiating frequency, the improvement comprising:

grounding ring means of conductive material spaced from and extending at least partially around the radiating element for limiting lateral radiation from the radiating element in the plane of the radiating element, and means electrically connecting the grounding ring means to the ground member

the distance between the radiating element and the ground ring means in a first direction perpendicular to a line connecting the first mentioned antenna with the other antenna is at least eleven percent of the wavelength of the electromagentic radiation radiating from the radiating element at the operating frequency.

15. The microstrip antenna of claim 14 wherein the width of the grounding ring means is less than the distance between the radiating element and the grounding ring means.

16. The microstrip antenna of claim 14 wherein the width of the grounding ring means is less than 1/4 inch.

17. The microstrip antenna of claim 14, wherein the grounding ring means is in the same plane as the radiating element.

18. The microstrip antenna of claim 14, wherein the grounding ring means extends entirely around the radiating element.

19. The microstrip antenna of claim 14 wherein the distance between the radiating element and the grounding ring means in a second direction perpendicular to the first direction is about fourteen percent of the wavelength of the electromagnetic radiation radiating from the radiating element at the operating frequency.

21. The microstrip antenna of claim 19 wherein the distance between the radiating element and the grounding ring means in the second direction is greater than the distance between the radiating element and the grounding ring means in the first direction.

20. A microstrip antenna comprising a ground member, a dielectric element on the ground member and a radiating element on the dielectric element for radiating a signal at a radiating frequency, a strip of conductive material forming a closed loop around the radiating element and generally coplanar with the conductive material, and means grounding the conductive strip, the conductive strip providing isolation for lateral radiation from the antenna, wherein the improvement comprises the provisions of the distance between the strip of conductive material on two sides of the radiating element being greater than the distance between the strip of conductive material on the other two sides of the radiating element.