Miniature integral antenna-radio apparatus

• US 4,862,181 A
• Filed: 10/30/1987
• Issued: 08/29/1989
• Est. Priority Date: 10/31/1986
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stamps, Douglass K. Jr., Balzano, Quirino, Ponce de Leon, Lorenzo A.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/115,735
• Time in Patent Office: 669 Days
• Field of Search: 343/702, 343/728, 343/741, 343/742, 343/855, 343/859, 343/866
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna

Abstract

An integral portable receiver/antenna system is provided which includes an isolation coupler element exhibiting a geometry which is substantially closed upon itself and which is situated between the receiver antenna and the input of the receiver. A portion of the antenna element is distributively coupled to a portion of the coupler element. The receiver/antenna system further includes a ground plane which is sufficiently close to a portion of the coupler element such that the ground plane is distributively coupled to the coupler element. The coupler element prevents the formation of undesired signal loss paths between the antenna and the receiver and provides for impedance matching the input of the receiver to the antenna. The coupler element also couples signals to the receiver input which would otherwise be lost to the ground plane.

Claims

1. An antenna comprising:

a ground plane;

an antenna element isolated from said ground plane and is geometrically configured to be substantially closed upon itself, said antenna element including first and second ends;

at least one capacitor coupled in series between the first and second ends of said antenna element, said capacitor being variable to permit tuning of said antenna element at an operating frequency; and

a coupler element, situated generally within said antenna element, a portion of said coupler element being substantially parallel with, and sufficiently close to, a portion of said antenna element to permit distributed coupling between said portion of said antenna element and said portion of said coupler element, said coupler element including an input end which is adapted to be coupled to a receiver, and a terminating end coupled to said ground plane through a second capacitor.

2. The antenna of claim 1 wherein said antenna element exhibits a substantially rectangular geometry.

3. The antenna of claim 1 wherein said coupler element exhibits a substantially rectangular geometry and said portion of said coupler element being substantially parallel to a portion of said antenna element includes at least one side of said coupler element being substantially parallel to a portion of one side of said antenna element.

4. The antenna according to claim 1 wherein said isolated antenna element provides a balanced signal output.

5. The antenna according to claim 1 wherein said input end of said coupler element is adapted to couple to an unbalanced input.

6. The antenna according to claim 1 wherein said coupler element further having an additional side situated sufficiently close to said ground plane to further permit distributed coupling between said additional side and said ground plane.

7. The antenna of claim 1 wherein said second capacitor for resonating said coupler element at a self resonant frequency substantially higher than the operating frequency of the antenna.

9. The receiver/antenna of claim 4 wherein said antenna means includes receiver component chamber means, situated within the space occupied by said antenna means, for containing receiver components therein.

10. The receiver/antenna of claim 4 wherein said antenna means includes slot means for reducing the capacitance between said antenna means and said isolation coupler means.

8. An integral portable receiver/antenna comprising:

a portable receiver housing;

a substrate situated within said housing, said substrate including first and second major opposed surfaces, and further including a ground plane situated on one of said surfaces;

antenna means, situated on said substrate and isolated from said ground plane, for capturing radio frequency signals at an operating frequency impinging thereon;

receiver means, situated on said substrate, for receiving radio frequency signals at the operating frequency, said receiver means including an input; and

isolation coupler means, coupled between said antenna means and the input of said receiver means, for coupling radio frequency signals from said antenna means to the input of said receiver means and for preventing the formation of signal paths between said antenna means and portions of said receiver means other than the input of said receiver means,

said isolation coupler means being self resonant at a frequency substantially higher than the operating frequency and including a transmission line portion which is distributively coupled to said antenna means.

11. The receiver/antenna according to claim 8 wherein said isolated antenna means provides a balanced signal output.

12. The receiver/antenna according to claim 8 wherein said input of said receiver means is an unbalanced input.

13. The receiver/antenna according to claim 8 wherein an additional portion of said isolation coupler means being situated sufficiently close to the ground plane to additionally permit distributed coupling thereto.

14. The receiver/antenna according to claim 13 wherein said additional portion of said isolation coupler means which couples to said ground plane further couples to said antenna means.