Antenna

• US 6,919,859 B2
• Filed: 09/09/2003
• Issued: 07/19/2005
• Est. Priority Date: 09/09/2003
• Status: Expired due to Term

• Current Assignee: PCTEL, Inc. (Amphenol Corporation)
• Original Assignee: PCTEL, Inc. (Amphenol Corporation)
• Inventors: McCarthy, Robert Daniel, Fix, Russell Alan
• Primary Examiner(s): Dinh, Trinh Vo
• Application Number:
  US10/658,732
• Publication Number:
  US 20050052336A1
• Time in Patent Office: 679 Days
• Field of Search: H01/Q00.1/36, H01/Q00.1/50, 343/895, 343/860, 343/845, 343/846, 343/850, 343/853, 343/701, 343/745
• US Class Current: 343/895
• 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 11/08 Helical antennas

Abstract

An antenna including a feed network; four or more helical radiating elements, and four or more impedance matching stubs each coupling a respective radiating element to ground in parallel with the feed network. The shunt stubs provide a reactance in parallel with the radiating elements to rotate the desired frequency locus about a constant admittance curve. Specifically, the shunt stubs rotate the desired frequency locus from a low resistance, capacitive impedance to 50 ohms purely resistive. The length of the stubs can be adjusted to control the inductance.

Claims

1. An antenna including:

a feed network;

four or more helical radiating elements;

four or more impedance matching elements each coupling a respective radiating element to ground in parallel with the feed network; and

a substrate which carries the radiating elements on a first side and a ground plane on a second side, wherein the substrate carries the impedance matching elements on the second side and each impedance matching element couples a respective radiating element to the ground plane in parallel with the feed network.

2. The antenna of claim 1 wherein each impedance matching element is a stub.

3. The antenna of claim 1 wherein each impedance matching element is an inductive element.

4. The antenna of claim 1 wherein each impedance matching element is a stub coupled to ground via a conductive short circuit connection.

5. The antenna of claim 1 wherein the antenna is a quadrifilar antenna having four radiating elements.

6. The antenna of claim 1 including four feed lines each connected to a respective radiating element at a respective junction, wherein each impedance matching element is connected at a connection point located at or adjacent to the junction.

7. The antenna of claim 6 wherein the connection point is located on the radiating element adjacent to the junction.

8. The antenna of claim 6 wherein the connection point is located on the feed line adjacent to the junction.

9. The antenna of claim 1 wherein the antenna is configured to transmit and/or receive circularly polarized radiation.

10. The network of claim 1 wherein the feed network is a microstrip feed network.

11. The network of claim 1, wherein the feed network includes a hybrid coupler.

12. The network of claim 11, wherein the hybrid coupler has no terminated port.

13. The network of claim 11 wherein the hybrid coupler is a ring hybrid.

14. The antenna of claim 1 wherein the feed network includes a 180°

hybrid coupler having a feed port, a 0°

port;

a 180°

port having an approximately 180°

phase difference with the 0°

port;

a first antenna port coupled to the 0°

port;

a second antenna port coupled to the 0°

port via a respective phased line, the second antenna port having an approximately 90°

phase difference with the first antenna port;

a third antenna port coupled to the 180°

port; and

a fourth antenna port coupled to the 180°

port via a respective phased line, the fourth antenna port having an approximately 90°

phase difference with the third antenna port.

15. The antenna of claim 1 wherein the feed network has an output impedance between 45 and 55 ohms.

16. The antenna of claim 1, wherein the radiating elements each have substantially the same length.

17. The antenna of claim 1, wherein the radiating elements are each coupled to the feed network at one end, and open circuited at another end.

18. An antenna including:

a feed network;

four or more helical radiating elements;

four or more impedance matching elements each coupling a respective radiating element to ground in parallel with the feed network;

a substrate which carries the radiating elements on a first side and a around plane on a second side, wherein each impedance matching element couples a respective radiating element to the ground plane in parallel with the feed network and each impedance matching element includes a plated-through hole passing through the substrate.

19. The antenna of claim 18 wherein each impedance matching element is a stub.

20. The antenna of claim 18 wherein each impedance matching element is an inductive element.

21. The antenna of claim 18 wherein each impedance matching element is a stub coupled to ground via a conductive short circuit connection.

22. The antenna of claim 18 wherein the antenna is a quadrifilar antenna having four radiating elements.

23. The network of claim 18 wherein the feed network is a microstrip feed network.

24. The network of claim 18 wherein the feed network includes a hybrid coupler.