JP2004147327A - Multiband antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiband antenna which is adjustable independently for transmission and reception of radio frequency energy. <P>SOLUTION: The multiband antenna 10 includes a conductive upper plate arranged in a spiral. In a preferred embodiment, a side-wall folded part 22 extends from the edge of the upper plate toward an earth plate 16. A short-circuit folded part connects the upper plate to the earth plate 16. The first area 12 of the upper plate is placed on the earth plate 16. The second area 13 of the upper plate extends passing the earth plate 16. Tuning is made by adjusting the length and other dimensions of the folded part. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an antenna for transmitting and receiving a radio frequency signal, and more particularly, to an antenna operable in multiple frequency bands.

In general, the performance of an antenna is related to the size, morphology and material composition and size of the antenna components, and the wavelength of the signal transmitted and received by the antenna, as well as the specific physical variables of the antenna (eg, the loop antenna). It is known that there is a relationship between the diameter and the length of the linear antenna.

Such relationships determine the operating variables of various antennas, including input impedance, gain, directivity, signal polarization and radiation patterns. Operable antennas must generally have a minimum size determined in quarter wavelengths (or multiples thereof) of the operating frequency. In this way, the energy lost due to the resistance loss can be effectively limited, and as a result, the transmitted or received energy can be maximized. For this reason, a quarter wavelength or half wavelength (1/2 wavelength) antenna is most commonly used.

With the breakthrough growth of wireless communication devices and systems, physically smaller, fewer obstacles, broadband or multiple frequency bands and / or multiple modes (eg, selectable radiation patterns or selectable signal polarization) The need for more operable, more efficient antennas is emerging. Conventional small communication equipment, such as handsets, do not provide enough space for typical quarter-wave and half-wave antennas. Thus, while operating in a given frequency band and providing other given antenna operating characteristics (input impedance, radiation pattern, signal polarization, etc.), the need for physically small antennas is increasing. .

According to the prior art, for at least a single component antenna, the following direct relationship exists between the physical size of the antenna and the antenna gain.

ここで，Ｒはアンテナを含む球の半径，βは伝播係数である。

Here, R is the radius of the sphere including the antenna, and β is the propagation coefficient.

Therefore, in order to increase the gain of the antenna, the size of the antenna must be large, but on the other hand, the user requires a small antenna, and contradiction arises between the two. In addition, in order to simplify system design and minimize costs, equipment designers and system operators need to be able to connect communication equipment to a variety of wireless services that operate in other frequency bands or operate in a wide band. It is desirable to use antennas that can operate effectively in multiple bands and / or wide bands. However, as described above, the gain is limited by the relationship between antenna frequency and effective antenna length (indicated by wavelength). In other words, the antenna gain is constant for any quarter-wave antenna having a particular geometry, ie, the effective antenna length at that operating frequency is a quarter wavelength of that operating frequency. One of the basic antennas used in many recent application fields is a half-wave dipole antenna.

(4) The radiation pattern is a normal donut shape, with most of the energy radiated uniformly in the azimuth direction and almost no energy in the elevation direction. In some communication equipment, the predetermined frequency bands are 1710 to 1990 MHz and 2110 to 2200 MHz. The half-wave dipole antenna is about 3.11 inches long at 1900 MHz, about 3.45 inches long at 1710 MHz, and about 2.68 inches long at 2200 MHz. Usually, the gain is about 2.15 dBi.

１ ／ The quarter-wave monopole antenna placed on the ground plane is obtained from a half-wave dipole antenna. The length of the antenna is a quarter wavelength, but operates in conjunction with the ground plane to provide the same performance as a half-wave dipole antenna. Therefore, the radiation pattern of the monopole antenna on the ground plate is the same as that of the half-wave dipole antenna, and the gain is usually about 2 dBi.

Shows a typical free space (ie, not above the ground plane) loop antenna (approximately 1/3 wavelength diameter) and also exhibits a donut shaped radiation pattern along the radiation axis, with a gain of approximately 3.1 dBi. The diameter of the loop antenna at 1900 MHz is about 2 inches. Usually, the input impedance of the loop antenna is 50Ω, which provides excellent matching characteristics.

A well-known patch antenna has a directional hemispherical range with a gain of about 4.7 dBi. This patch antenna is small, but has a relatively narrow bandwidth as compared to a quarter-wave or half-wave antenna.

In consideration of the excellent performance of quarter-wave and half-wave antennas, conventional antennas are generally configured such that the antenna length is about one-quarter wavelength of the radiation frequency, and the antenna operates on a ground plane. To do. Having this magnitude allows the antenna to be more easily excited, operating at or near the resonance frequency, limiting the energy lost by resistive losses and maximizing the transmitted energy.

However, since the operating wavelength increases and decreases as the operating frequency increases and decreases, there is a problem that the size of the antenna component must increase and decrease in proportion.

Accordingly, it is an object of the present invention to provide a new and improved multi-band antenna that can be adjusted to operate in various frequency bands.

Antenna designers are trying to use a so-called “Slow Wave Structure” in which the structural physical size does not match the effective electrical size. As noted above, the effective antenna size must be on the order of half a wavelength (or quarter wavelength above the ground plane) for advantageous radiation and low loss characteristics. Generally, a slow wave structure is defined as one in which the phase velocity of the traveling wave is smaller than the light flux in free space. The wave degree is the inner product of the wavelength and the frequency, and is as follows when the dielectric constant and the magnetic permeability of the medium are taken into consideration.

(4) Since the frequency does not change during propagation of the slow wave, if the radio wave travels slower than the light beam (that is, the phase velocity is smaller), the wavelength of the structure becomes smaller than the wavelength in free space.

Accordingly, for example, the half-wavelength slow wave structure is shorter than the half-wavelength structure traveling as the light beam c. Slow wave structures separate the relationship between physical length, resonance frequency and wavelength. Such a slow wave structure may be used as a component of an antenna or an antenna radiating structure.

(4) In a slow wave structure, the effective electrical length of such a structure is greater than the effective electrical length of the light beam propagation structure because the phase velocity of the traveling wave is smaller than the light flux in free space. Thus, the resulting resonance frequency of the slow wave structure is the same as that of the half-wave dipole antenna, so that, for example, the slow wave propagation structure is physically smaller than the light beam propagation structure.

In order to solve the above problems, according to a first aspect of the present invention, the antenna has a shape of a structure connected to a ground plate via a gap for transmitting and receiving a radio frequency signal. The antenna of the present invention includes a spiral upper plate separated by one or more edges. A shorting element (formed in the preferred embodiment of a folded conductor) extends from the top plate to the ground plate to electrically connect the top plate to the ground plate. Side walls extend from the edge of the top plate toward the ground plate.

In order to solve the above problem, according to a second aspect of the present invention, there is provided a multi-band antenna connected to an underlying ground plane for transmitting and receiving radio frequency energy, wherein the helical antenna is surrounded by one or more edges. An upper plate, a short-circuit element extending from the lower surface of the upper plate toward the ground plate so as to electrically connect the upper plate to the ground plate, and a short-circuiting element extending from the edge of the upper plate toward the ground plate. And an extending side wall.

In order to solve the above problems, in a third aspect of the present invention, a helical upper plate having a ground plate, a second region, a first region covering the ground plate, and an electrical connection with the upper plate. , A first folded conductor portion extending from the upper plate, and a second folded conductor portion extending from the upper plate.

According to a fourth aspect of the present invention, there is provided a multi-band antenna connected to a ground plate through a gap for transmitting and receiving radio frequency energy, the multi-band antenna having one or more edges. A first region of the upper plate facing the ground plate when operating with the ground plate, including a helical upper plate and side walls extending from an edge of the upper plate toward the ground plate. And a second region of the upper plate extends past an edge of the ground plate.

According to a fifth aspect of the present invention, there is provided a multi-band antenna connected to a ground plate for transmitting and receiving radio frequency energy, wherein the spiral upper plate is connected to the upper plate. A first folding element extending from the upper plate toward the ground plate, a second folding element extending from the upper plate, and a side wall extending from an edge of the upper plate for coupling to the ground plate. Features.

In order to solve the above problems, according to a sixth aspect of the present invention, there is provided a multi-band antenna connected to a ground plate via a gap for transmitting and receiving radio frequency energy, wherein a slot is provided inside. A conductive plate having a first region, a second region, and one or more edges, the conductive plate extending from the edge of the plate toward the ground plate when the antenna operates with the ground plate; A first region disposed opposite the ground plate when operating with the ground plate, wherein the second region extends past an edge of the ground plate. I do.

According to the present invention, the antenna can be adjusted to operate in various frequency bands by adding a bending element and / or adjusting the length of the bending element. Other additional operating frequency bands can be created by the addition of folding elements. The addition of specific bending elements operating in one frequency band does not affect operation in other bands. Thus, the antenna of the present invention can have a separate adjustable operating frequency band. According to the prior art, it is known that changing one or the size of the physical characteristics of an antenna generally affects all resonance frequencies of the antenna. The antenna according to the invention does not have such a limitation. In the case of the antenna according to the present invention, all resonance frequencies can be influenced by adjusting the size (for example, length, width, height from the ground plate).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

(First Embodiment)
The antenna according to the present embodiment includes a small spiral radiating portion, and one or more bent structures are connected to the spiral radiating portion. For this reason, an optimum operating characteristic can be exhibited in a volume smaller than the quarter wavelength structure formed on the ground plate. The antenna according to the present embodiment can be easily formed by stamping a required shape from an empty metal plate. The stamp area is shaped as needed, and the folded area is fixed in a suitable position. Due to the small volume of the antenna, it has a spatial advantage when it is installed in a communication device handset and other application devices. In addition, the antenna according to the present embodiment can be formed by patterning and etching a conductive plate provided on a dielectric substrate.

First, the configuration of the antenna according to the present embodiment will be described with reference to FIG. FIG. 1 is a plan view showing the configuration of the antenna 10 according to the present embodiment.

As shown in FIG. 1, the antenna 10 according to the present embodiment is made using a relatively thin conductive material (for example, copper) plate, and further includes an upper plate having an inner spiral region 12 and an outer spiral region 13. 11 is provided. In another method, the top plate 11 is formed from a conductive plate with material removed from a region near the center of the plate that extends to the edge of the conductive plate. For example, the material is removed to form a helical slot in top plate 11. The antenna 10 is disposed on a dielectric substrate 14 and includes a ground plate 16 extending from an edge 18 of the dielectric substrate 14 to a boundary line 20. Therefore, the ground plate 16 does not extend below the entire antenna 10.

(4) With the above configuration, a capacitance is provided between the upper plate 11 and the dielectric substrate 14, so that the antenna 10 has characteristics as described later. For example, the distance between the upper plate 11 and the dielectric substrate 14 can be about 5 mm. If the distance between the antenna and the dielectric substrate is changed, the resonance characteristics of the antenna 10 change.

The antenna 10 further includes a folding element 22 located in a region 23 between the boundary line 20 and the edge 24 on the dielectric substrate. Folding element 22 is not electrically connected to region 23 but is mechanically connected to support antenna 10.

(4) A signal is supplied to or received from the antenna via the power supply line 30 and the antenna power supply unit 32 provided on the dielectric substrate 14. In general, a power supply connector (not shown) is physically attached to the dielectric substrate in the area 33 and includes a power supply fin electrically connected to the power supply line 30 and a ground fin electrically connected to the ground plate 16. Is provided. The antenna shown in FIG. 1 does not include a predetermined bending region provided in another embodiment described later.

(Second embodiment)
Next, a configuration of the antenna according to the second embodiment will be described with reference to FIGS. FIG. 2 is a plan view showing the configuration of the antenna 10 including the bending element 22 and the bending element 402 (not shown in FIG. 1). FIG. 3 is a front view showing the configuration of the antenna 10 including the bending element 22 and the bending element 402 (not shown in FIG. 1).

折 り As shown in FIG. 2, the bending element 40 is electrically connected between the area 41 of the upper plate 11 and the ground plate 16. As shown in detail in FIG. 3, the folding element 22 comprises a vertical region 43 and an arm 44 extending from the vertical region 43 and arranged to make physical contact with the region 23 of the dielectric substrate 14. Is done. However, the arm 44 is not electrically connected to the ground plate 16.

FIG. 4 shows the configuration of the bending element 40. FIG. 4 is a sectional view taken along line 4-4 in FIG. As shown schematically, the terminal end 42 of the folding element 40 is connected to ground. The distance d can be, for example, about 1 inch.

Next, FIG. 5 shows the configuration of an electrical equivalent circuit of the antenna 10. FIG. 5 is a circuit diagram showing a configuration of an electrical equivalent circuit of the antenna 10.

キ ャ パ シ タ As shown in FIG. 5, the capacitor 50 indicates a capacitance between the outer spiral region 13 and the ground plate 16. Capacitor 52 indicates the capacitance between internal spiral region 12 and ground plate 16. Both capacitors 50 and 52 are affected by the vertical distance between top plate 11 and ground plate 16. Adjusting the position of the boundary line 20 (see FIG. 1) with respect to the edge 18 (or the edge 24) changes the values of the capacitances 50 and 52. Therefore, one of the techniques used to affect such capacitance and general antenna characteristics is to adjust the distance between the boundary 20 and the edge 18 (or edge 24). is there.

The capacitance 54 indicates a capacitance between the inner spiral region 12 and the outer spiral region 13. In the figure, 56 corresponds to the bending element 40 shorted to ground. The fold region 22 is indicated by reference numeral 58, which is not connected to ground, but is instead shown as opened. Generally, as shown in FIG. 5, the right side component of the antenna feed 32 affects the performance in the low band, and the left side component of the antenna feed 32 affects the performance in the high band.

The antenna 10 according to the present embodiment operates, for example, in a cellular frequency band of about 880 to 960 MHz (low band) and a frequency band of a personal communication system (PCS) of about 1.710 to 1.990 GHz (high band). Shows a resonance operation. The radiation pattern in the low band is omnidirectional (common donut pattern), and the radiation pattern in the high band has an elevation pattern (Elevational Pattern) in which energy is mainly emitted in the elevation direction.

The high band frequency is adjusted by adjusting a physical characteristic such as the length of the bending region 40 to cause resonance in a band near 1.5 GHz which is the frequency band of the global positioning system (GPS), for example. it can. In order to change performance characteristics including the operating frequency of the antenna 10, the shape and size of the bending element 22 can be variously changed. In the present embodiment, the schematic size of the antenna 10 can be, for example, about 0.4 inch long and about 0.4 inch wide.

(Third embodiment)
Next, a configuration of the antenna 70 representing the resonance condition in three frequency bands according to the third embodiment will be described with reference to FIGS. FIG. 6 is a plan view showing the configuration of the antenna 70 according to the third embodiment, which represents resonance conditions in three frequency bands. FIG. 7 is a front view showing a configuration of an antenna 70 representing a resonance condition in three frequency bands according to the third embodiment.

Generally, the antenna 70 includes an inner spiral region 12 and an outer spiral region 13 like the antenna 10 (FIG. 1). However, the antenna 70 according to the present embodiment further includes a bent element that is deformed as compared with the antenna 10 as shown in FIG.

As shown in FIG. 7, the antenna 70 according to the present embodiment includes the bending element 40 and the antenna feed unit 32 that function in the same manner as that described for the antenna 10. The antenna 70 further comprises a folding element 71 having regions 72 and 73 electrically connected to each other. Region 72 extends from top plate 11 and region 73 is disposed on or near the dielectric substrate, but is not electrically coupled to ground plate 16.

Next, the configuration of the bending element 71 according to the present embodiment will be described with reference to FIG. FIG. 8 is a cross-sectional view of the bending element 71 taken along line 8-8 in FIG.

こ の As shown in FIG. 8, the bending element 71 is disposed on the dielectric substrate 14 but is not electrically connected to the ground plate 16. In the present embodiment, the distance dd can be, for example, about 0.3 inches.

The antenna 70 further comprises a folding element 74 having a vertical area 75 and an arm 76.

Antenna 70 exhibits resonance conditions in the 820-890 MHz band for cellular communications, the 1.5 GHz band for Global Positioning System (GPS) communications, and the 2.5 GHz band for wireless local area network communications. Works as follows.

Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, it is needless to say that the present invention is not limited to the examples. It is clear that a person skilled in the art can conceive various changes or modifications within the scope of the claims, and these naturally belong to the technical scope of the present invention. I understand.

The present invention is applicable to multi-band antennas.

FIG. 2 is a plan view showing a configuration of the antenna 10 according to the first embodiment. It is a top view showing the composition of the bending element concerning a 2nd embodiment, and the antenna which has a bending element. It is a front view showing the composition of the antenna which has a bending element and a bending element concerning a 2nd embodiment. FIG. 4 is a sectional view of a bending element of the antenna shown in FIGS. 2 and 3. FIG. 4 is a circuit diagram showing an electric equivalent circuit of the antenna of FIGS. 2 and 3. FIG. 13 is a plan view illustrating a configuration of an antenna according to a third embodiment that represents resonance conditions in three frequency bands. It is a front view showing the composition of the antenna which expresses a resonance condition in three frequency bands concerning a 3rd embodiment. FIG. 8 is a cross-sectional view of the bending element taken along line 8-8 of FIG. 6.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 Antenna 11 Upper plate 12 Internal spiral region 13 External spiral region 14 Dielectric substrate 16 Grounding plate 18 Edge of dielectric substrate 22 Bending element 30 Feeding line 32 Antenna feeder

Claims (48)

A multi-band antenna coupled to an underlying ground plane for transmitting and receiving radio frequency energy,
A spiral upper plate surrounded by one or more edges;
A short-circuit element extending from the lower surface of the upper plate toward the ground plate so as to electrically connect the upper plate to the ground plate;
A side wall extending from an edge of the upper plate toward the ground plate. 2. The multi-band antenna according to claim 1, wherein the multi-band antenna covers only a part of the upper plate while the multi-band antenna is operable with the ground plate. In the upper plate,
3. The multi-band antenna according to claim 2, wherein an area of the portion covering the ground plate is adjustable so as to affect the performance of the antenna. In the upper plate,
The portion covering the ground plate includes a first region of the upper plate from which the short-circuit element extends;
Excluding a second region in which the side wall extends,
The multi-band antenna according to claim 2, wherein: The ground plate is made of a conductive material disposed on the first region of the substrate;
The second region of the substrate has no conductive material;
The side wall is disposed to cover the second region;
The multi-band antenna according to claim 1, wherein: The multi-band antenna according to claim 1, wherein the upper plate includes an inner spiral region connected to an outer spiral region. The multi-band antenna according to claim 1, wherein the upper plate has a continuous spiral structure formed of a conductive material. The multi-band antenna according to claim 1, wherein the short-circuit element has a bent-type conductor. The multi-band antenna according to claim 8, wherein the bent-type conductor has an elongated transmission line having a zigzag shape. Said bendable conductor comprising an elongated transmission line further comprising a first region and a second region;
The first region and the second region are electrically connected to each other, and are disposed substantially parallel to the upper plate;
The multi-band antenna according to claim 8, wherein: The antenna is mounted so as to cover the ground plate,
The first region and the second region are disposed between the upper plate and the ground plate substantially in parallel with the ground plate.
The multi-band antenna according to claim 10, wherein: The multi-band antenna according to claim 1, further comprising a feed element connected to the upper plate. In addition, it includes a feeding element,
The upper plate has an inner spiral region and an outer spiral region,
The feed element is disposed at an end of the outer spiral region;
The multi-band antenna according to claim 1, wherein: The antenna is disposed on a dielectric substrate;
Further, the grounding plate includes a conductive power supply region insulated from the grounding plate,
The power supply region is electrically connected to the power supply element;
The multi-band antenna according to claim 13, wherein: 15. The multi-band antenna according to claim 14, wherein the feed element has a conductive strip extending from the top plate toward the conductive feed area on the dielectric substrate. The side wall forms a substantially right angle with the edge of the top plate;
The multi-band antenna according to claim 1, wherein: Ground plate,
A helical upper plate having a second region and a first region covering the ground plate;
A power supply element electrically connected to the upper plate;
A first bent conductor portion extending from the upper plate;
A second bent conductor portion extending from the upper plate.
A multi-band antenna, characterized in that: The ground plate includes a dielectric substrate, and includes a conductive material disposed on a first region of the dielectric substrate, wherein the second region of the substrate is free of the conductive material, and A first region of the plate substantially covers a first region of the substrate;
The multi-band antenna according to claim 17, wherein: The first bent conductor portion extends from a first region of the upper plate, and further comprises a zigzag elongated conductor portion;
The bent conductor portion connects the upper plate to the ground plate,
The multi-band antenna according to claim 18, wherein: Further, the upper plate includes a second region extending through an edge of the ground plate,
The second bent conductor portion includes a first conductive element extending from an edge of the second region, and a second conductive element extending from the second conductive element;
The multi-band antenna according to claim 17, wherein: 21. The multi-band antenna according to claim 20, wherein an angle formed between the second region of the upper plate and the first conductive element is substantially 90 degrees. 21. The multi-band antenna according to claim 20, wherein an angle formed between the first conductive element and the second conductive element is substantially 90 degrees. A multi-band antenna coupled to a ground plane through a gap for transmitting and receiving radio frequency energy,
A spiral upper plate having one or more edges;
A side wall extending from an edge of said top plate toward said ground plate,
When operating with the ground plate, a first region of the top plate is disposed opposite the ground plate, and a second region of the top plate extends past an edge of the ground plate.
A multi-band antenna, characterized in that: 24. The multi-band antenna according to claim 23, wherein the side wall extends past an edge of the ground plane. Further, the antenna includes a short-circuit element for electrically connecting the upper plate to the ground plate,
The multi-band antenna according to claim 24, wherein: 26. The multi-band antenna according to claim 25, wherein the short-circuit element comprises a bent conductor extending from the upper plate. And a dielectric substrate having first and second substrate regions, wherein the ground plate is disposed on the first substrate region, and wherein the first region of the upper plate is the first substrate region. The multi-band antenna according to claim 23, wherein the multi-band antenna is disposed so as to face the antenna. 28. The multi-band antenna according to claim 27, wherein said sidewall is located on said second substrate area. A multi-band antenna coupled to a ground plane for transmitting and receiving radio frequency energy,
A spiral upper plate,
A first folding element extending from the top plate toward the ground plate to couple the top plate to the ground plate;
A second folding element extending from said top plate;
A side wall extending from an edge of the upper plate;
A multi-band antenna comprising: 30. The multi-band antenna according to claim 29, wherein the distance between the top plate and the ground plate is selected to achieve required antenna performance parameters. 31. The multi-band antenna according to claim 29, wherein an area of the upper plate is overlapped with the ground plate while the antenna operates together with the ground plate. 32. The multi-band antenna according to claim 31, wherein the area of the overlapping region is adjustable so as to change the performance characteristics of the antenna. 33. The multi-band antenna according to claim 32, wherein the first bending element is disposed in the overlapping area. 30. The multi-band antenna according to claim 29, wherein the upper plate has an inner spiral region and an outer spiral region, and the inner spiral region is in electrical communication with the outer spiral region. 30. The multi-band antenna according to claim 29, wherein the upper plate has a continuous spiral structure made of a conductive material. 30. The multi-band antenna according to claim 29, wherein the second bending element extends from the upper plate toward the ground plate, and is formed by a substantially L-shaped bending element. The second folding element includes a first region extending from the top plate and a second region extending from the first region, wherein the length of the second region is greater than the length and width of the top plate. 37. The multi-band antenna according to claim 36, wherein the antenna is small. 30. The multi-band antenna according to claim 29, wherein the first folding element comprises an elongated folding transmission line having a region substantially parallel to the top plate. 30. The multi-band antenna according to claim 29, wherein the first folding element comprises an elongated folded transmission line further comprising at least two interconnected regions substantially parallel to the top plate. The antenna is attached to the ground plate with a gap therebetween, and the first bending element is substantially parallel to the upper plate, and is substantially parallel to each other in a direction substantially parallel to the ground plate. With two elongated areas,
30. The multi-band antenna according to claim 29, wherein: The antenna further includes a feed element;
30. The multi-band antenna according to claim 29, wherein: The power supply element extends from the upper plate toward the ground plate, the ground plate is disposed on a dielectric substrate, and the dielectric substrate is electrically connected to the power supply element and insulated from the ground plate. 42. The multi-band antenna according to claim 41, further comprising a conductive feed region. 30. The multi-band antenna of claim 29, wherein the second folding element is oriented between the side wall and the first folding element. A first region disposed substantially at right angles to the upper plate; and a second region connected to the first region and disposed substantially at right angles to the first region. With an area,
30. The multi-band antenna according to claim 29, wherein: A multi-band antenna coupled to a ground plane through a gap for transmitting and receiving radio frequency energy,
A conductive plate having a slot therein, the conductive plate having a first region, a second region, and one or more edges;
A sidewall extending from the edge of the plate toward the ground plate when the antenna operates with the ground plate;
The multi-band antenna of claim 1, wherein when operating with the ground plate, the first region is disposed opposite the ground plate, and the second region extends past an edge of the ground plate. 46. The multi-band antenna according to claim 45, wherein the side wall extends from the second region. 25. The multi-band antenna according to claim 24, further comprising short-circuit means extending from the first region to electrically connect the upper plate to the ground plate. 47. The multi-band antenna according to claim 46, wherein the slot defines a spiral shape.

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