WO2010044086A1

WO2010044086A1 - Multi-band antennas

Info

Publication number: WO2010044086A1
Application number: PCT/IL2009/000977
Authority: WO
Inventors: Snir Azulay
Original assignee: Galtronics Corporation Ltd.
Priority date: 2008-10-13
Filing date: 2009-10-13
Publication date: 2010-04-22

Abstract

A multi-band antenna including a first antenna element having a first band, a second antenna element defining a capacitor together with at least part of the first antenna element, the second antenna element being in at least partially surrounding relationship with the first antenna element and a third antenna element galvanically connected to the second antenna element and defining an inductor, the first, second and third antenna elements having a second band defined by the capacitance of the capacitor and the inductance of the inductor.

Description

MULTI-BAND ANTENNAS

REFERENCE TO RELATED APPLICATIONS

Reference is hereby made to U.S. Provisional Patent Application Serial

No. 61/104,806, filed October 13, 2008 and entitled "SINGLE/MULTI BANDS

ELECTRICALLY SMALL ANTENNA", the disclosure of which is hereby incorporated by reference and priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i).

FIELD OF THE INVENTION

The present invention relates to antennas generally and more generally to multi-band antennas.

BACKGROUND OF THE INVENTION

The following publications are believed to represent the current state of the art: 1. "Low profile Omnidirectional Zoeroth-order Resonator (ZOR) antenna" Jae-Gon Lee and Jeong-Hae Lee

2. "Radiation Efficiency of the Metamaterial Zero-order Resonator Antenna" David Vrba and Milan Polivka

3. "Transmission Line Approach of Left handed (LH) Materials and Microstrip Implementation of an Artificial LH Transmission line" C. Caloze and T. Itoh

4. "Metamaterial-Based Efficient Electrically Small Antenna" Richard W. Ziolkowski and Aycan Erentok

5. "An Efficient Electrically Small antenna Designed for VHF and UHF Application" Richard W. Ziolkowski 6. "Infinite wavelength Resonant Antennas With monopolar Radiation

Pattern Based on Periodic Structure" Anthony Lai, Kevin M.K.H Leong and Tatsuo Itoh

SUMMARY OF THE INVENTION

The present invention seeks to provide improved multi-band antennas. There is thus provided in accordance with a preferred embodiment of the present invention a multi-band antenna including a first antenna element having a first band, a second antenna element defining a capacitor together with at least part of the first antenna element, the second antenna element being in at least partially surrounding relationship with the first antenna element and a third antenna element galvanically connected to the second antenna element and defining an inductor, the first, second and third antenna elements having a second band defined by the capacitance of the capacitor and the inductance of the inductor.

In accordance with a preferred embodiment of the present invention the multi-band antenna also includes a fourth antenna element galvanically connected to a ground plane and a fifth antenna element galvanically connected to the first antenna element and capacitively coupled to the fourth antenna element.

Preferably the fourth and fifth antenna elements together have a third band. More preferably the third band is an extension of at least one of the first and second bands. Alternatively the third band is separate from the first and second bands.

Preferably the antenna elements are formed on a flexible substrate and mounted on a relatively rigid substrate. More preferably the flexible substrate is wrapped around the relatively rigid substrate.

In accordance with a preferred embodiment of the present invention the antenna elements are formed on a relatively rigid substrate. Preferably the antenna elements are formed on one side of a relatively rigid substrate. Alternatively the antenna elements are formed on at least two sides of a relatively rigid substrate.

In accordance with a preferred embodiment of the present invention the first antenna element is a monopole antenna. Preferably the second antenna element has a generally U shape and is disposed in partially surrounding relationship with the first antenna element. Preferably the third antenna element galvanically connects the second antenna element to a ground plane.

In accordance with a preferred embodiment of the present invention the fourth antenna element is galvanically connected to a ground plane. Preferably the fifth antenna element is galvanically connected to the first antenna element. Preferably the fourth antenna element has a generally U shape and is disposed in partially surrounding relationship with the fifth antenna element.

In accordance with a preferred embodiment of the present invention the first antenna element has a partially conical and partially cylindrical form. Preferably the second antenna element is in the shape of a cap which partially surrounds the partially conical and partially cylindrical first antenna element.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig. 1 is a simplified pictorial illustration of a multi-band antenna constructed and operative in accordance with a preferred embodiment of the present invention formed on a flexible substrate and mounted on a relatively rigid substrate;

Fig. 2 is a simplified pictorial illustration of a multi-band antenna constructed and operative in accordance with another preferred embodiment of the present invention formed on a flexible substrate and mounted on a relatively rigid substrate;

Fig. 3 is a simplified pictorial illustration of a multi-band antenna constructed and operative in accordance with still another preferred embodiment of the present invention formed on a flexible substrate and mounted on a relatively rigid substrate;

Figs. 4A & 4B are simplified pictorial illustrations of opposite surfaces of a multi-band antenna constructed and operative in accordance with a further embodiment of the present invention; Fig. 5 is a simplified pictorial illustration of a multi-band antenna constructed and operative in accordance with yet a further embodiment of the present invention; and

Figs. 6A₅ 6B and 6C are respectively, pictorial, partially sectional and sectional illustrations of portions of a multi-band antenna constructed and operative in accordance with another embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to Fig. I₅ which is a simplified pictorial illustration of one embodiment of a multi-band antenna 100 constructed and operative in accordance with a preferred embodiment of the present invention, formed on a flexible substrate 102 and mounted on a relatively rigid substrate 104.

As seen in Fig. 1 , the multi-band antenna 100 preferably includes a first antenna element 110, such as a monopole antenna having a feed point 112 and having a first band. A second antenna element 120 defines a distributed capacitor together with at least part of the first antenna element 110. The capacitance of the capacitor is determined by the gap between the first element 110 and the second element 120. In the illustrated embodiment, the second element 120 has a generally U shape and is disposed in partially surrounding relationship with the first antenna element 110.

A third antenna element 122 galvanically connects the second antenna element 120 to a ground plane 124 and defines an inductor where the inductance of the inductor is mainly determined by the width and the length of third element 122. The inductance of the inductor is further influenced by wrapping the antenna 100 around relatively rigid substrate 104, as shown. It is appreciated that the first, second and third antenna elements, 1 10, 120 and 122 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

Typical radiation bands of an embodiment of the antenna of Fig. 1 are as follows:

First hand - 1710-1990MHz

Second band - 824-960MHz Typical radiation bands of a further embodiment of the antenna of Fig. 1 are as follows:

First band - 5GHz

Second hand - 2.4GHz

Reference is now made to Fig. 2, which is a simplified pictorial illustration of one embodiment of a multi-band antenna 200 constructed and operative in accordance with a another preferred embodiment of the present invention, formed on a flexible substrate 202 and mounted on a relatively rigid substrate 204.

As seen in Fig. 2, the multi-band antenna 200 preferably includes a first antenna element 210, such as a monopole antenna having a feed point 212 and having a first band. A second antenna element 220 defines a distributed capacitor together with at least part of the first antenna element 210. The capacitance of the capacitor is determined by the gap between the first element 210 and the second element 220. In the illustrated embodiment, the second element 220 has a generally U shape and is disposed in partially surrounding relationship with the first antenna element 210. A third antenna element 222 galvanically connects the second antenna element 220 to a ground plane 224 and defines an inductor where the inductance of the inductor is mainly determined by the width and the length of third element 222. The inductance of the inductor is further influenced by wrapping the antenna 200 around relatively rigid substrate 204, as shown. It is appreciated that the first, second and third antenna elements, 210, 220 and 222 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

A fourth antenna element 240 is galvanically connected to ground plane 242 and a fifth antenna element 250 is galvanically connected to the first antenna element 210 and capacitively coupled to the fourth antenna element 240. The capacitance of the capacitor is determined by the gap between the fourth element 240 and the fifth element 250. In the illustrated embodiment, the fourth element 240 has a generally U shape and is disposed in partially surrounding relationship with the fifth antenna element 250.

It is appreciated that the fourth and fifth antenna elements, 240 and 250 respectively have a third band defined by the capacitance value of the capacitor defined thereby.

Typical radiation bands of the antenna of Fig. 2 are as follows: First hand - 1850-1990MHz

Second hand - 824-960MHz Third band - 1710-1880MHz Reference is now made to Fig. 3, which is a simplified pictorial illustration of one embodiment of a multi-band antenna 300 constructed and operative in accordance with a preferred embodiment of the present invention, formed on a flexible substrate 302 and mounted on a relatively rigid substrate 304. As seen in Fig. 3, the multi-band antenna 300 preferably includes a first antenna element 310, such as a monopole antenna having a feed point 312 and having a first band. A second antenna element 320 defines a distributed capacitor together with at least part of the first antenna element 310. The capacitance of the capacitor is determined by the gap between the first element 310 and the second element 320. In the illustrated embodiment, the second element 320 has a generally U shape and is disposed in partially surrounding relationship with the first antenna element 310. Second antenna element 320 differs from the second antenna element 120 in the embodiment of Fig. 1 in that the parallel legs 321 thereof are substantially wider than the corresponding legs of second antenna element 120. The variation in the width of the legs 321 changes the operational frequency, by changing the capacitance value of the capacitor.

A third antenna element 322 galvanically connects the second antenna element 320 to a ground plane 324 and defines an inductor where the inductance of the inductor is mainly determined by the width and the length of third element 322. The inductance of the inductor is further influenced by wrapping the antenna 300 around relatively rigid substrate 304, as shown. It is appreciated that the first, second and third antenna elements, 310, 320 and 322 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

Typical radiation bands of the antenna of Fig. 3 are as follows: First band - 1850-1990MHZ Second hand - 700MHz

Reference is now made to Figs. 4A & 4B, which are simplified pictorial illustrations of opposite surfaces of a multi-band antenna 400, constructed and operative in accordance with a further embodiment of the present invention, formed on a relatively rigid substrate 404.

As seen in Figs. 4A & 4B, the multi-band antenna 400 preferably includes a first antenna element 410, such as a monopole antenna having a feed point 412 and having a first band. A second antenna element 420 defines a capacitor together with at least part of the first antenna element 410. The capacitance of the capacitor is determined by the gap between the first element 410 and the second element 420. In the illustrated embodiment, the second element 420 has a generally U shape and is disposed in partially surrounding relationship with the first antenna element 410.

A third antenna element 422 formed on an opposite surface of substrate 404, galvanically connects the second antenna element 420 to a ground plane 424 and also defines an inductor where the inductance of the inductor is mainly determined by the width and the length of third element 422. It is appreciated that the first, second and third antenna elements, 410, 420 and 422 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

A fourth antenna element 440 is galvanically connected to a ground plane 442 and a fifth antenna element 450 is galvanically connected to the first antenna element 410 and capacitively coupled to the fourth antenna element 440. The capacitance of the capacitor is determined by the gap between the fourth element 440 and the fifth element 450. In the illustrated embodiment, the fourth element 440 has a generally U shape and is disposed in partially surrounding relationship with the fifth antenna element 450.

It is appreciated that the fourth and fifth antenna elements, 440 and 450 respectively have a third band defined by the capacitance value of the capacitor defined thereby.

Typical radiation bands of the antenna of Figs. 4A & 4B are as follows:

First hand - 1850-1990MHZ

Second hand - 824-960MHz Third band - 1710-1880MHz

Reference is now made to Fig. 5, which is a simplified pictorial illustration of a multi-band antenna 500, constructed and operative in accordance with a further embodiment of the present invention, formed on a relatively rigid substrate 504. As seen in Fig. 5, the multi-band antenna 500 preferably includes a first antenna element 510, such as a monopole antenna having a feed point 512 and having a first band. A second antenna element 520 defines a capacitor together with at least part of the first antenna element 510. The capacitance of the capacitor is determined by the gap between the first element 510 and the second element 520. In the illustrated embodiment, the second element 520 has a generally U shape and is disposed in partially surrounding relationship with the first antenna element 510. A third antenna element 522 galvanically connects the second antenna element 520 to a ground plane 524 and also defines an inductor where the inductance of the inductor is mainly determined by the width and the length of third element 522. It is appreciated that the first, second and third antenna elements, 510, 520 and 522 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

A fourth antenna element 540 is galvanically connected to ground plane 524 and a fifth antenna element 550 is galvanically connected to the first antenna element 510 and capacitively coupled to the fourth antenna element 540. The capacitance of the capacitor is determined by the gap between the fourth element 540 and the fifth element 550. In the illustrated embodiment, the fourth element 540 has a generally U shape and is disposed in partially surrounding relationship with the fifth antenna element 550.

It is appreciated that the fourth and fifth antenna elements, 540 and 550 respectively have a third band defined by the capacitance value of the capacitor defined thereby.

Typical radiation bands of the antenna of Fig. 5 are as follows: First hand - 1850-1990MHZ

Second hand - 824-960MHz

Third band - 1710-1880MHz

Reference is now made to Figs. 6A, 6B and 6C, which are respectively, pictorial, partially sectional and sectional illustrations of portions of a multi-band antenna 600 constructed and operative in accordance with a yet further embodiment of the present invention. As seen in Figs. 6A - 6C₅ the multi-band antenna 600 preferably includes a first antenna element 610, such as a partially conical and partially cylindrical monopole antenna having a feed point 612 insulatively mounted with respect to a ground plane 614 and having a first band. A second antenna element 620 defines a capacitor together with part of the first antenna element 610. The capacitance of the capacitor is determined by the gap between the first element 610 and the second element 620. In the illustrated embodiment, the second element 620 is in the shape of a cap which partially surrounds part of the cylindrical portion of first antenna element 610.

A third antenna element 622 galvanically connects the second antenna element 620 to the ground plane 614 and also defines an inductance. It is appreciated that the first, second and third antenna elements, 610, 620 and 622 respectively, have a second band defined by the capacitance value of the capacitor and the inductance value of the inductor.

Typical radiation bands of the antenna of Figs. 6A - 6C are as follows:

First hand - 1500MHz-6500MHz

Second hand - 700-960MHz

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the invention includes both combinations and subcombinations of the various features described hereinabove as well as modifications and variations thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.

Claims

CLAIMS:

1. A multi-band antenna comprising: a first antenna element having a first band; a second antenna element defining a capacitor together with at least part of said first antenna element, said second antenna element being in at least partially surrounding relationship with said first antenna element; and a third antenna element galvanically connected to said second antenna element and defining an inductor, said first, second and third antenna elements having a second band defined by the capacitance of said capacitor and the inductance of said inductor.

2. A multi-band antenna according to claim 1 and also comprising: a fourth antenna element galvanically connected to a ground plane; and a fifth antenna element galvanically connected to said first antenna element and capacitively coupled to said fourth antenna element.

3. A multi-band antenna according to claim 2 and wherein said fourth and fifth antenna elements together have a third band.

4. A multi-band antenna according to claim 3 and wherein said third band is an extension of at least one of said first and second bands.

5. A multi-band antenna according to claim 3 and wherein said third band is separate from said first and second bands.

6. A multi-band antenna according to any of the preceding claims wherein said antenna elements are formed on a flexible substrate and mounted on a relatively rigid substrate.

7. A multi-band antenna according to claim 6 wherein said flexible substrate is wrapped around said relatively rigid substrate.

8. A multi-band antenna according to any of claims 1 - 5 wherein said antenna elements are formed on a relatively rigid substrate.

9. A multi-band antenna according to claim 8 wherein said antenna elements are formed on one side of a relatively rigid substrate.

10. A multi-band antenna according to claim 8 wherein said antenna elements are formed on at least two sides of a relatively rigid substrate.

1 1. A multi-band antenna according to any of claims 1 - 10 wherein said first antenna element is a monopole antenna.

12. A multi-band antenna according to any of claims 1 - 11 wherein said second antenna element has a generally U shape and is disposed in partially surrounding relationship with said first antenna element.

13. A multi-band antenna according to any of claims 1 - 12 wherein said third antenna element galvanically connects said second antenna element to a ground plane.

14. A multi-band antenna according to any of claims 2 - 10 wherein said fourth antenna element is galvanically connected to a ground plane.

15. A multi-band antenna according to any of claims 2 - 10 and 14 wherein said fifth antenna element is galvanically connected to said first antenna element.

16. A multi-band antenna according to any of claims 2 - 10 and 14 - 15 wherein said fourth antenna element has a generally U shape and is disposed in partially surrounding relationship with said fifth antenna element.

17. A multi-band antenna according to claim 1 wherein said first antenna element has a partially conical and partially cylindrical form.

18. A multi-band antenna according to claim 17 wherein said second antenna element is in the shape of a cap which partially surrounds said first antenna element.