Multi-band antenna structure

• US 7,088,299 B2
• Filed: 10/28/2004
• Issued: 08/08/2006
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: DSP Group Incorporated (Synaptics Incorporated)
• Original Assignee: DSP Group Incorporated (Synaptics Incorporated)
• Inventors: Sainati, Robert, Siegler, Michael J.
• Primary Examiner(s): Ho, Tan
• Application Number:
  US10/976,166
• Publication Number:
  US 20050116869A1
• Time in Patent Office: 649 Days
• Field of Search: 343/702, 343/745, 343/749, 343/795, 343/820, 343/821, 343/822
• US Class Current: 343/745
• CPC Class Codes: H01Q 1/2258 used with computer equipment
• CPC Class Codes: H01Q 1/2275 associated to expansion card or bus, e.g. in PCMCIA, PC cards, Wireless USB
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407
• CPC Class Codes: H01Q 9/36 with top loading

Abstract

The invention provides a multi-band antenna structure for use in a wireless communication system. The antenna structure includes integrated inductive elements and capacitive elements that function as a tuned circuit to allow the antenna structure to operate in multiple frequency ranges. In particular, the capacitive elements electromagnetically couple to the inductive elements. The capacitive elements provide the inductive elements with parallel capacitance at a given set of frequencies, thereby providing the antenna structure with frequency selectivity. At a particular frequency range, the inductive elements act as short circuits, thereby lengthening the radiating elements, which radiate energy at the particular frequency. At another frequency range, the inductive components act as open circuits, virtually shortening the radiating elements in order to radiate the higher frequencies. In this manner, the multi-band antenna structure operates within multiple frequency ranges.

Claims

1. An antenna comprising:

a radiating component to transmit and receive signals, wherein the radiating component includes a first radiating element having a first integrated inductive element, and a second radiating element having a second integrated inductive element; and

first and second capacitive elements, wherein the first capacitive element electromagnetically couples to the first integrated inductive element and the second capacitive element electromagnetically couples to the second integrated inductive element to form a tuned circuit that allows the antenna to operate in more than one frequency range,

wherein the radiating component is formed on a first layer of a multi-layer circuit structure, and the capacitive elements are formed on a second layer of the multi-layer circuit structure.

2. The antenna of claim 1, wherein the first capacitive element is substantially vertically aligned with the first inductive element, and the second capacitive element is substantially vertically aligned with the second inductive element.

3. The antenna of claim 1, further comprising one or more intermediate layers to separate the first and second layers.

4. The antenna of claim 1, wherein a portion of the first radiating element is disposed as a meander line to form the first inductive element, and a portion of the second radiating element is disposed as a meander line to form the second inductive element.

5. The antenna of claim 1, wherein the tuned circuit allows the antenna to operate in a 2.4 GHz frequency range and a 5.0 GHz frequency range.

6. The antenna of claim 1, wherein the first capacitive element has a surface area that is substantially commensurate with a region containing the first inductive element, and the second capacitive element has a surface area that is substantially commensurate with a region containing the second inductive element.

7. The antenna of claim 1, wherein the radiating component comprises one of an arrow shaped radiating component, a T-shaped radiating component, and a Y-shaped radiating component.

8. The antenna of claim 1, further comprising a conductive strip feed-line that electromagnetically couples to the radiating component to directly feed the radiating component, wherein the conductive strip feed-line forms a balun.

9. A wireless communication device comprising:

a transmitter;

a receiver; and

an antenna coupled to at least one of the transmitter and the receiver, the antenna including;

a radiating component to transmit and receive signals, wherein the radiating component includes a first radiating element having a first integrated inductive element, and a second radiating element having a second integrated inductive element; and

first and second capacitive elements, wherein the first capacitive element electromagnetically couples to the first integrated inductive element and the second capacitive element electromagnetically couples to the second integrated inductive element to form a tuned circuit that allows the antenna to operate in more than one frequency range,

wherein the radiating component is formed on a first layer of a multi-layer circuit structure, and the capacitive elements are formed on a second layer of the multi-layer circuit structure.

10. The device of claim 9, wherein the first capacitive element is substantially vertically aligned with the first inductive element, and the second capacitive element is substantially vertically aligned with the second inductive element.

11. The device of claim 9, further comprising one or more intermediate layers to separate the first and second layers.

12. The device of claim 9, wherein a portion of the first radiating element is disposed as a meander line to form the first inductive element, and a portion of the second radiating element is disposed as a meander line to form the second inductive element.

13. The device of claim 9, wherein the tuned circuit allows the antenna to operate in a 2.4 GHz frequency range and a 5.0 GHz frequency range.

14. The device of claim 9, wherein the transmitter and the receiver operating according to at least one of the IEEE 802.11a, 802.11b, 802.11e and 802.11g protocols.

15. The device of claim 9, wherein the device is a wireless local area networking card.

16. The device of claim 9, wherein the device is a wireless local area networking access point.

17. The device of claim 9, wherein the first capacitive element has a surface area that is substantially commensurate with a region containing the first inductive element, and the second capacitive element has a surface area that is substantially commensurate with a region containing the second inductive element.

18. The device of claim 9, wherein the radiating component comprises one of an arrow shaped radiating component, a T-shaped radiating component, and a Y-shaped radiating component.

19. The antenna of claim 9, further comprising a conductive strip feed-line that electromagnetically couples to the radiating component to directly feed the radiating component, wherein the conductive strip feed-line forms a balun.

20. A method comprising transmitting and receiving wireless signals via an antenna comprising a radiating component that includes a first radiating element having a first integrated inductive element, and a second radiating element having a second integrated inductive element, and first and second a capacitive elements, wherein the first capacitive element electromagnetically couples to the first integrated inductive element and the second capacitive element electromagnetically couples to the second integrated inductive element to form a tuned circuit that allows the antenna to operate in more than one frequency range, wherein the radiating component is formed on a first layer of a multi-layer circuit structure, and the capacitive elements are formed on a second layer of the multi-layer circuit structure.

21. The method of claim 20, wherein the first capacitive element is substantially vertically aligned with the first inductive element, and the second capacitive element is substantially vertically aligned with the second inductive element.

22. The method of claim 20, further comprising one or more intermediate layers to separate the first and second layers.

23. The method of claim 20, wherein a portion of the first radiating element is disposed as a meander line to form the first inductive element and a portion of the second radiating element is disposed as a meander line to form the second inductive element.

24. The method of claim 20, further comprising transmitting and receiving wireless signals in a 2.4 GHz frequency range and a 5.0 GHz frequency range.

25. The method of claim 20, wherein the first capacitive element has a surface area that is substantially commensurate with a region containing the first inductive element, and the second capacitive element has a surface area that is substantially commensurate with a region containing the second inductive element.

26. The method of claim 20, wherein the radiating component comprises one of an arrow shaped radiating component, a T-shaped radiating component, and a Y-shaped radiating component.

27. The method of claim 20, further comprising a conductive strip feed-line that electromagnetically couples to the radiating component to directly feed the radiating component, wherein the conductive strip feed-line forms a balun.