Antenna and semiconductor device having the same

• US 7,605,761 B2
• Filed: 11/13/2007
• Issued: 10/20/2009
• Est. Priority Date: 11/30/2006
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koen, Takaaki, Yanagisawa, Makoto
• Primary Examiner(s): Barnie; Rexford N
• Assistant Examiner(s): Hammond; Crystal L
• Application Number:
  US11/979,990
• Publication Number:
  US 20080129606A1
• Time in Patent Office: 707 Days
• Field of Search: 343/700.MS, 343/741, 343/702
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

An antenna capable of receiving circularly polarized waves and performing impedance matching between the antenna and an IC (integrated circuit) of a semiconductor device, and a semiconductor device having such an antenna. The antenna has a first conductor pattern with a loop configuration having a cut section, a second conductor pattern, a third conductor pattern, and a feeding section. A first end portion of the second conductor pattern and a first end portion of the third conductor pattern are connected to the first conductor pattern. A second end portion of the second conductor pattern and a second end portion of the third conductor pattern are connected to the feeding section. The total length of the second conductor pattern is longer than the total length of the third conductor pattern, and the second conductor pattern is placed closer to the cut section than the third conductor pattern is.

Claims

1. An antenna comprising:

a substrate;

a first conductor pattern over the substrate;

a second conductor pattern over the substrate;

a third conductor pattern over the substrate; and

a feeding section having a first terminal and a second terminal,

wherein the first conductor pattern has a loop configuration with a cut section,

wherein a first end portion of the second conductor pattern and a first end portion of the third conductor pattern are connected to the first conductor pattern,

wherein a second end portion of the second conductor pattern is electrically connected to the first terminal of the feeding section,

wherein a second end portion of the third conductor pattern is electrically connected to the second terminal of the feeding section,

wherein the total length of the second conductor pattern is longer than the total length of the third conductor pattern, and

wherein the first end portion of the second conductor pattern is placed closer to the cut section than the first end portion of the third conductor pattern is.

2. The antenna according to claim 1, wherein assuming that the total length of the first conductor pattern is L, the feeding section is provided in a position whose distance from the cut section is in a range of L/6 to L/4.

3. The antenna according to claim 1, wherein the first conductor pattern, the second conductor pattern, and the third conductor pattern are formed of the same material.

4. The antenna according to claim 1, wherein the second conductor pattern and the third conductor pattern extend parallel to each other.

5. An antenna comprising:

a substrate;

a first conductor pattern over the substrate;

a second conductor pattern over the substrate;

a third conductor pattern over the substrate; and

a feeding section having a first terminal and a second terminal,

wherein a first end portion of the first conductor pattern is connected to the second conductor pattern,

wherein a second end portion of the first conductor pattern is connected to the third conductor pattern,

wherein a first end portion of the second conductor pattern is electrically connected to the first terminal of the feeding section,

wherein a first end portion of the third conductor pattern is electrically connected to the second terminal of the feeding section,

wherein a second end portion of the second conductor pattern and a second end portion of the third conductor pattern are insulated,

wherein a conductor pattern made of the second conductor pattern and the third conductor pattern that are electrically connected through the feeding section has a loop configuration,

wherein the connection portion of the first end portion of the first conductor pattern and the second conductor pattern is placed closer to the cut section than the connection portion of the second end portion of the first conductor pattern and the third conductor pattern,

wherein the total length of the third conductor pattern is longer than the total length of the second conductor pattern, and

wherein a distance from the connection portion of the first end portion of the first conductor pattern and the second conductor pattern to the first end portion of the second conductor pattern is longer than a distance from the connection portion of the second end portion of the first conductor pattern and the third conductor pattern to the first end portion of the third conductor pattern.

6. The antenna according to claim 5, wherein assuming that the total length of the second conductor pattern is L₂, the total length L₃ of the third conductor pattern is 3L₂ to 5L₂.

7. The antenna according to claim 5, wherein the first conductor pattern, the second conductor pattern, and the third conductor pattern are formed of the same material.

9. The semiconductor device according to claim 7, wherein assuming that the total length of the first conductor pattern is L, the integrated circuit is provided in a position whose distance from the cut section is in a range of L/6 to L/4.

10. The semiconductor device according to claim 9, wherein assuming that the total length of the second conductor pattern is L₂, the total length L₃ of the third conductor pattern is 3L₂ to 5L₂.

8. A semiconductor device comprising:

a substrate;

an integrated circuit having a first terminal and a second terminal, over the substrate; and

an antenna electrically connected to the integrated circuit over the substrate,

wherein the antenna includes a first conductor pattern, a second conductor pattern, and a third conductor pattern,

wherein the first conductor pattern has a loop configuration with a cut section,

wherein a first end portion of the second conductor pattern and a first end portion of the third conductor pattern are connected to the first conductor pattern,

wherein a second end portion of the second conductor pattern is electrically connected to the first terminal of the integrated circuit,

wherein a second end portion of the third conductor pattern is electrically connected to the second terminal of the integrated circuit,

wherein the total length of the second conductor pattern is longer than the total length of the third conductor pattern, and

wherein the first end portion of the second conductor pattern is placed closer to the cut section than the first end portion of the third conductor pattern is.

11. The semiconductor device according to claim 8, wherein the first conductor pattern, the second conductor pattern, and the third conductor pattern are formed of the same material.

12. The semiconductor device according to claim 8, wherein the integrated circuit includes a battery, the battery being wirelessly charged from outside.

13. The antenna according to claim 8, wherein the second conductor pattern and the third conductor pattern extend parallel to each other.

14. A semiconductor device comprising:

a substrate;

an integrated circuit having a first terminal and a second terminal, over the substrate; and

an antenna electrically connected to the integrated circuit over the substrate,

wherein the antenna includes a first conductor pattern, a second conductor pattern, and a third conductor pattern,

wherein a first end portion of the first conductor pattern is connected to the second conductor pattern,

wherein a second end portion of the first conductor pattern is connected to the third conductor pattern,

wherein a first end portion of the second conductor pattern is electrically connected to the first terminal of the integrated circuit,

wherein a first end portion of the third conductor pattern is electrically connected to the second terminal of the integrated circuit,

wherein a second end portion of the second conductor pattern and a second end portion of the third conductor pattern are insulated,

wherein a conductor pattern made of the second conductor pattern and the third conductor pattern that are electrically connected through the integrated circuit has a loop configuration,

wherein the connection portion of the first end portion of the first conductor pattern and the second conductor pattern is placed closer to the cut section than the connection portion of the second end portion of the first conductor pattern and the third conductor pattern,

wherein the total length of the third conductor pattern is longer than the total length of the second conductor pattern, and

wherein a distance from the connection portion of the first end portion of the first conductor pattern and the second conductor pattern to the first end portion of the second conductor pattern is longer than a distance from the connection portion of the second end portion of the first conductor pattern and the third conductor pattern to the first end portion of the third conductor pattern.

15. The semiconductor device according to claim 14, wherein the first conductor pattern, the second conductor pattern, and the third conductor pattern are formed of the same material.

16. The semiconductor device according to claim 14, wherein the integrated circuit includes a battery, the battery being wirelessly charged from outside.

17. An antenna comprising:

a substrate;

a first conductor pattern over the substrate;

a second conductor pattern over the substrate;

a third conductor pattern over the substrate; and

a feeding section having a first terminal and a second terminal,

wherein the second conductor pattern extends from a first portion of the first conductor pattern,

wherein the third conductor pattern extends from a second portion of the first conductor pattern,

wherein the first conductor pattern has a loop configuration with a cut section,

wherein an end portion of the second conductor pattern is electrically connected to the first terminal of the feeding section,

wherein an end portion of the third conductor pattern is electrically connected to the second terminal of the feeding section,

wherein the first portion of the first conductor pattern is placed closer to the cut section than the second portion of the first conductor pattern is, and

wherein the total length of the second conductor pattern is longer than the total length of the third conductor pattern.

18. The antenna according to claim 17, wherein assuming that the total length of the first conductor pattern is L, the feeding section is provided in a position whose distance from the cut section is in a range of L/6 to L/4.