KR101049724B1 - Independently adjustable multi-band antenna with bends - Google Patents

Abstract

An antenna for transmitting and receiving radio frequency energy. The antenna according to the present invention includes a conductive top plate configured in a spiral shape. In one embodiment, the sidewall bends extend from the edge of the top plate in the direction of the ground plate. The short bend connects the top plate to the ground plate. The first area of the top plate lies on the ground plate. The second region of the top plate extends beyond the ground plane. Tuning is possible by adjusting the length of the bend and a different size.

Antenna, Bending Elements, Multiband

Description

Independently Tunable Multiband Meanderline Loaded Antenna             

1 is a perspective view of an antenna constructed in accordance with the present invention;

2 and 3 are plan and end views, respectively, of another embodiment of an antenna constructed in accordance with the present invention;

4 is a cross-sectional view of the bending element of the antenna shown in FIGS. 2 and 3;

5 is an equivalent electric diagram for the antenna of FIGS. 2 and 3;

6 through 8 are various views of a second embodiment of an antenna constructed according to the present invention.

This application claims the priority benefit of US Provisional Patent Application, filed No. 60 / 420,214, filed Oct. 22, 2002.                         

The present invention relates generally to antennas for transmitting and receiving radio frequency signals, and more particularly to antennas operable in multiple frequency bands.

In general, the performance of an antenna is related to the size, shape, material composition, and size of the antenna components, and also the wavelength of the signal to be transmitted and received by the antenna and the specific physical variables of the antenna (e.g., the diameter of the loop antenna and the length of the linear antenna). And the like).

This relationship determines the operating parameters of the various antennas, including input impedance, gain, directivity, signal polarization, and radiation pattern. Operable antennas should generally have a minimum size determined in units of one quarter wavelength (or multiples thereof) of the operating frequency. By doing so, it is possible to effectively limit the energy lost by the resistive losses and thus maximize the transmit or receive energy. For this reason, quarter-wave or half-wave (half-wave) antennas are most commonly used.

Significant growth in wireless communications devices and systems allows for physically smaller, less visible, operation in broadband or multiple frequency bands and / or multiple modes (e.g., selectable radiation pattern or selectable signal polarization). There is a need for more efficient antennas. Conventional small communication equipment, such as handsets, does not provide enough space for common quarter- and half-wavelength antennas. Thus, there is an increasing need for antennas that are physically compact while operating in the frequency band of interest and providing other necessary antenna operating characteristics (input impedance, radiation pattern, signal polarization, etc.).                         

According to the prior art, for at least a single-element antenna, there is a direct relationship between the physical size of the antenna and the antenna gain as follows.

Where R is the radius of the sphere containing the antenna and β is the propagation factor.

Thus, to increase the antenna gain, the size of the antenna must be large, while the user requires a small antenna, causing a contradiction between the two. As an additional restriction, to simplify system design and minimize costs, equipment designers and system operators can efficiently operate in multiple bands and / or broadband to enable telecommunications equipment to access a variety of wireless services that operate within different frequency bands or over wider broadband. You want to use an antenna that can work with. However, as mentioned above, the gain is limited by the relationship between the antenna frequency and the effective antenna length (expressed in wavelength). In other words, the antenna gain is constant for all quarter-wave antennas with a particular geometry, and in other words, the effective antenna length at that operating frequency is one-quarter wavelength of the operating frequency. One of the basic antennas used in many applications today is a half-wave dipole antenna.                         

The radiation pattern is a conventional donut shape, where most of the energy is uniformly radiated in the azimuth direction and little energy is radiated in the elevation direction. The frequency bands of interest in some communications equipment are 1710-1990 MHz and 2110-2200 MHz. The half-wavelength 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. Typical gain is about 2.15 dBi.

Quarter-wavelength monopole antennas placed on ground planes can be found from half-wavelength dipole antennas. The antenna is 1/4 wavelength long, but works in conjunction with the ground plane to approximate the performance of a half-wavelength dipole antenna. Therefore, the radiation pattern of the ground plane upper monopole antenna is similar to the half-wave dipole antenna and the typical gain is about 2 dBi.

A typical free space loop antenna (not on top of the ground plane) (about 1/3 wavelength in diameter) also exhibits a donut-shaped radiation pattern along the radial axis, with a gain of about 3.1 dBi. Have At 1900 MHz, the loop antenna is about 2 inches in diameter. The input impedance of a typical loop antenna is 50 ohms, which provides excellent matching characteristics.

Well-known patch antennas have a directional hemispherical coverage with a gain of about 4.7 dBi. Patch antennas, although small, have a relatively narrow bandwidth when compared to quarter- or half-wavelength antennas.

In view of the superior performance of quarter- and half-wavelength antennas, conventional antennas are generally constructed such that the antenna length is approximately one-quarter wavelength of the radiation frequency, allowing the antenna to operate on a ground plane. This size allows the antenna to be more easily excited and operate at or near the resonant frequency, as well as limiting the energy dissipated by resistive losses to maximize transmission energy. However, as the operating frequency is increased / decreased, the operating wavelength is decreased / increased, and thus there is a problem that the size of the antenna component must be proportionally reduced / increased.

Antenna designers are attempting to use the so-called "Slow Wave Structure" where the physical size of the structure does not match the effective electrical size. As mentioned above, the effective antenna size should be in half-wave (or quarter-wavelength above ground plane) units for favorable radiation and low loss characteristics. In general, the slow wave structure is defined as the phase velocity of the traveling wave is smaller than the luminous flux in free space. The velocity of the wave is as follows, considering the internal wavelength and frequency, and the permittivity and permeability of the medium.

The frequency does not change during slow wave propagation, so if propagation is slower than the speed of light (ie, the phase velocity is smaller), the wavelength inside the structure is smaller than the wavelength in free space.

Thus, for example, the half-wavelength slow wave structure is shorter than the half-wave structure traveling at the light flux c. The slow wave structure separates the relationship between physical length, resonant frequency and wavelength. This slow wave structure can be used as an antenna component or antenna radiation structure.

Since the phase velocity of the traveling wave in the slow wave structure is smaller than the speed of light in free space, the effective electrical length of this structure is larger than the effective electrical length of the structure propagating waves in the light flux. The resulting resonant frequency of the slow wave structure is therefore the same as that of a half-wave dipole, so that, for example, a structure that propagates slow waves will be physically smaller than a structure that propagates waves at the speed of light.

An antenna according to an embodiment of the present invention has a shape of a connection structure spaced apart from the ground plate for transmitting and receiving radio frequency signals. The antenna includes a spiral-shaped top plate separated by one or more edges. A shorting element (formed by a bent conductor in the preferred embodiment) extends from the top plate in the direction of the ground plate to electrically connect the top plate to the ground plate. Sidewalls extend from the top edge toward the ground plane.

The above and other features of the present invention will become more apparent from the following detailed description of the invention. In the following description, like reference numerals designate like parts in all of the other drawings. The drawings are not to be construed for purposes other than to illustrate the principles of the invention.

Before giving a detailed description of the antenna device according to the invention, it is to be understood that the invention is due to a novel and non-obvious combination of various components. Accordingly, the components according to the invention are represented by the typical components in the drawings, and represent only specific details appropriate for the present invention, and thus, disclose a detailed structure apparent to those skilled in the art having the effects described herein. Does not interfere with doing

The antenna according to the present invention includes a compact spiral radiator, and one or more bent structures are connected to the spiral radiator. Thus, it is possible to provide optimum operating characteristics in a volume smaller than a quarter wave structure formed on the ground plate. The antenna can be easily formed by imprinting the required shape from the blank metal plate. The stamped area is shaped as needed, and the bent area is fixed at an appropriate position. The small volume of the antenna gives it a spatial advantage when installed in communication device handsets and other applications. In another embodiment, the antenna according to the present invention may be formed by patterning and etching a conductive plate disposed on a dielectric substrate.

1 is a perspective view of an antenna 10 according to an embodiment of the present invention. The antenna 10 is made using a plate of relatively thin conductive material (e.g., copper) and further includes an inner spiral segment 12 and an outer spiral segment 13 It includes a top plate (11). Alternatively, the top plate 11 is formed of a plate of conductive material from which material is removed from the region near the center of the plate extending to the plate edge of the conductive material. In one embodiment, the material is removed to form a helical slot in the top plate 11. The antenna 10 is disposed on the dielectric substrate 14, and includes a ground plate 16 extending from the edge 18 of the dielectric substrate 14 to the boundary line 20. Thus, the ground plate 16 does not extend under the entire antenna 10. Having such a feature causes capacitance between the top plate 11 and the dielectric substrate 14 to have the characteristics of the antenna 10 as described in detail below. In one embodiment, the distance between the top plate 11 and the dielectric substrate 14 is about 5 mm. Changing the distance between the antenna and the dielectric substrate changes the resonance characteristics of the antenna 10.

 The antenna 10 further includes a Meanderline Element 22 lying in an area 23 between the boundary line 20 and the edge 24 on the dielectric substrate. The bending element 22 is not electrically connected to the region 23 but is mechanically connected to support the antenna 10.

The signal is supplied (feeded) to or received from the antenna via a feed line trace 30 formed on the dielectric substrate 14 and an antenna feed 32. In general, a feed connector (not shown in FIG. 1) is physically attached to the dielectric substrate in region 33, the feed connector being connected to a feed pin and ground plate 16 that are in electrical contact with feed line line 30. It has a ground pin in electrical contact. The embodiment of FIG. 1 does not include the specific bending region provided in the embodiment to be described below.

2 and 3 are plan and front views of an antenna 10 according to another embodiment, including bending element 22 and bending element 40 (the second bending element is not shown in FIG. 1), respectively. The bending element 40 is electrically connected between the area 41 of the top plate 11 and the ground plate 16. As best shown in FIG. 3, the bending element 22 consists of a vertical region 43 and an arm 44 extending from the vertical region and arranged to be in physical contact with the region 23 of the dielectric substrate 14. . However, arm 44 is not electrically connected to ground plate 16.

One preferred form of the bending element 40 is shown in cross section as in FIG. 4, taken along the 4-4 plane of FIG. 2. As schematically indicated, the end 42 of the bending element 40 is connected to ground. In one embodiment, the distance d is about 1 inch.

An equivalent electrical circuit of the antenna 10 is shown in FIG. 5. Capacitor 50 represents the capacitance between outer spiral region 13 and ground plate 16. Capacitor 52 represents the capacitance between inner spiral region 12 and ground plate 16. Capacitors 50 and 52 are both affected by the vertical distance between top plate 11 and ground plate 16. In addition, when the position of the boundary line 20 (refer to FIG. 1) with respect to the edge 18 (or the edge 24) is adjusted, capacitance values 50 and 52 change. Thus, one of the techniques used to influence this capacitance and general antenna characteristics is to adjust the distance between the boundary line 20 and the edge 18 or edge 24.

Capacitance 54 indicates the capacitance between inner and outer helix regions 12, 13. Reference numeral 56 corresponds to the bending element 40 shorted to ground. The bend area 22 is indicated by reference numeral 58, which is not connected to ground but is marked as open instead. In general, as shown in FIG. 5, the right component of the antenna feeder 32 affects low band performance and the left component of the antenna feeder 32 affects high band performance.

The antenna 10 according to an embodiment of the present invention operates in a cellular frequency band of about 880 to 960 MHz (low band) and in a frequency band of a personal communication system of about 1.710 to 1.990 GHz (high band). Resonance behavior is shown. The radiation pattern in the low band is omnidirectional (general donut pattern), and the radiation pattern in the high band has an elevational pattern in which energy is mainly radiated in an elevation direction. The high band frequency can be adjusted by adjusting physical properties such as the length of the bend area 40, for example, to cause resonance in a band near 1.5 GHz, which is the frequency band of the global positioning system (GPS). In order to change the performance characteristics including the operating frequency of the antenna 10, the shape or size of the bending element 22 may be variously changed. In one embodiment, the approximate size of the antenna 10 is about 0.4 inches long and about 0.4 inches wide.

6 is a plan view of the antenna 70 showing resonance conditions in three frequency bands. In general, antenna 70 includes an inner spiral region 12 and an outer spiral region 13 as shown in FIG. 1 for antenna 10. However, antenna 70 additionally has an additional bending element that is modified when compared to antenna 10.

7 is a front view of the antenna 70. Antenna 70 includes a bending element 40 and an antenna feeder 32 that function in the same manner as described for antenna 10. The antenna 70 further comprises a bending element 71 having electrically connected areas 72 and 73. Region 72 extends from top plate 11, and region 73 is disposed on or near the dielectric substrate but is not electrically connected to ground plate 16. A cross-sectional view of the bending element 71 along the 8-8 plane of FIG. 6 is shown in FIG. 8. As shown, the bend element 71 is disposed on the dielectric substrate 14 but is not electrically connected to the ground plate 16. In one embodiment, the distance dd is about 0.3 inches.

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

Antenna 70 exhibits resonance conditions in the 820-890 MHz band for cellular communication, 1.5 GHz band for Global Positioning System (GPS) communication, and 2.5 GHz band for Wireless Local Area Network Communication. To make it work.

In general, according to the technique according to the present invention, the antenna as shown in FIG. 1 can be adjusted to operate in various frequency bands by addition of bending elements and / or length adjustment of the shown bending elements. Other additional operating frequency bands may be created by the addition of bending elements. The addition of specific bending elements operating in one frequency band does not affect operation in other bands. Thus, the antenna may have separate adjustable operating frequency bands. According to the prior art it is known that changing the size or size of one of the antenna physical properties generally affects all resonance frequencies of the antenna. The antenna according to the invention does not have this limitation. In addition, the antenna according to the present invention may affect all resonance frequencies by adjusting the size (eg, length, width, height from the ground plane, etc.).

The antenna architecture according to the present invention has been described as useful for operating in one or more frequency bands. While the invention has been described and illustrated in particular applications and examples, the principles disclosed herein provide a basic principle of varying antenna shape and the like in various ways. Many modifications are possible within the scope of the invention. Accordingly, the invention is only limited by the following claims.

Claims (48)

An antenna connected to a ground plane disposed on the floor for transmitting and receiving radio frequency energy, One or more edges divided into an inner spiral region and an outer spiral region, wherein a portion of the inner spiral region and an outer spiral region cover the ground plate, and the inner spiral region and the outer spiral region except for the portion The remaining portion of the spiral top plate is formed so as not to cover the ground plate; A shorting element extending from the lower surface of the upper plate in the direction of the ground plate to electrically connect the upper plate to the ground plate; And a sidewall extending from the upper plate edge toward the ground plate. The method of claim 1, And wherein only a portion of the top plate covers the ground plate while the antenna is capable of operating with the ground plate. The method of claim 2, And an area of the top plate covering the ground plate is adjustable to affect antenna performance. The method of claim 2, A portion of the upper plate covering the ground plate is a first region of the upper plate from which the shorting element extends, and the remaining portion of the upper plate not covering the ground plate is a second region from which the side wall extends. Antenna. The method of claim 4, wherein And the ground plate is made of a conductive material disposed on a first region of the substrate, wherein the second region of the substrate is free of conductive material, and the sidewall is disposed to cover the second region. The method of claim 1, The outer spiral region and the inner spiral region are electrically connected to each other. The method of claim 1, And the top plate comprises a continuous spiral structure formed of a conductive material. The method of claim 1, And the shorting element comprises a bent conductor. The method of claim 8, The bent conductor comprises a zig-zag-shaped elongated transmission line. The method of claim 8, The bent conductor has an elongated transmission line further comprising a first region and a second region, wherein the first region and the second region are electrically connected and arranged parallel to the top plate. Characterized by an antenna. 11. The method of claim 10, And the antenna is mounted to cover the ground plate, and the first region and the second region are disposed between the top plate and the ground plate to be parallel to the ground plate. The method of claim 1, And an feeding element connected to the top plate. The method of claim 1, And a feed element, wherein the top plate comprises an inner spiral region and an outer spiral region, wherein the feed element is disposed at a distal end of the outer spiral region. An antenna connected to a ground plane disposed on the floor for transmitting and receiving radio frequency energy, One or more boundary regions separated by an inner and outer spiral region, a portion of the inner and outer spiral region covering the ground plate, and the remaining portions of the inner and outer spiral region except the portion are the ground A spiral top plate formed not to cover the plate; A shorting element extending from the lower surface of the upper plate in the direction of the ground plate to electrically connect the upper plate to the ground plate; Sidewalls extending from the edge of the upper plate toward the ground plate; A feed element connected to the top plate; And A conductive feeding region disposed on a dielectric substrate on which the antenna is disposed and insulated from the ground plate and electrically connected to the feeding element; An antenna comprising: The method of claim 14, And said feed element comprises a conductive strip extending from said top plate to said conductive feed area on said dielectric substrate. The method of claim 1, And the side wall forms a right angle with the top plate edge. Ground plate; A first region of the inner spiral region and an outer spiral region covering the ground plate and a second region of the inner spiral region and the outer spiral region not covering the ground plate; Spiral tops; A feeding element electrically connected to the top plate; A first bent conductor portion extending from the top plate; And, A second bent conductor portion extending from the top plate; Antenna comprising a. The method of claim 17, 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 dielectric substrate is free of conductive material, and the first region of the top plate is the dielectric substrate. And an antenna covering the first region of the antenna. The method of claim 18, And the first bent conductor portion extends from the first region of the top plate and further comprises a zigzag elongated conductor portion, wherein the bent conductor portion connects the top plate to the ground plate. The method of claim 17, And the second bent conductor portion comprises a first conductive element extending from an edge of the second region and a second conductive element extending from the second conductive element. The method of claim 20, And an angle formed between the second region of the upper plate and the first conductive element is 90 degrees. The method of claim 20, And the angle formed between the first conductive element and the second conductive element is 90 degrees. An antenna connected to a ground plate that is spaced apart to transmit and receive radio frequency energy, A first region of the inner and outer spiral regions covering the ground plate and a first region of the inner spiral region and an outer spiral region by one or more edges, and the inner and outer spiral regions not covering the ground plate A spiral top plate comprising a second region of the spiral region; And A side wall extending in a direction from the edge of the upper plate toward the ground plate; And, when operating with the ground plate, the first region of the top plate is disposed to face the ground plate, and the second region of the top plate extends beyond an edge of the ground plate. . The method of claim 23, wherein And the side wall extends beyond an edge of the ground plane. The method of claim 24, The antenna further comprises a shorting element for electrically connecting the top plate to the ground plate. The method of claim 25, And said shorting element comprises a bent conductor portion extending from said top plate. The method of claim 23, wherein Further comprising a dielectric substrate comprising a first region and a second substrate region, wherein the ground plate is disposed on the first region of the dielectric substrate, and the first region of the top plate is the first region of the dielectric substrate. And an antenna facing each other. 28. The method of claim 27, And the sidewalls rest on the second region of the dielectric substrate. An antenna connected to a ground plane for transmitting and receiving radio frequency energy, A first region of the inner spiral region and an outer spiral region which is divided into an inner spiral region and an outer spiral region, and overlaps the ground plate, and a second region of the inner spiral region and an outer spiral region not overlapping the ground plate; Spiral tops comprising; A first bending element extending from the top plate in the direction of the ground plate to connect the top plate to the ground plate; A second bending element extending from the top plate; And, Sidewalls extending from an edge of the top plate; Antenna comprising a. 30. The method of claim 29, And the distance between the top plate and the ground plate is selected to achieve the required performance parameters of the antenna. 30. The method of claim 29, And wherein the top plate region overlaps the ground plate while the antenna is operating with the ground plate. The method of claim 31, wherein And the area of the overlapping area can be adjusted to change the performance characteristics of the antenna. 33. The method of claim 32, And the first bending element is disposed in the overlapping area. 30. The method of claim 29, And the inner spiral region is in electrical communication with the outer spiral region. 30. The method of claim 29, And the top plate comprises a continuous spiral structure of conductive material. 30. The method of claim 29, And the second bending element extends from the upper plate in the direction of the ground plate and is formed of an L-shaped bending element. 37. The method of claim 36, The second bending element includes a first area extending from the top plate and a second area extending from the first area, the length of the second area being less than the length and width of the top plate. 30. The method of claim 29, And the first bent element includes an elongated meanderline transmission line having an area parallel to the top plate. 30. The method of claim 29, And the first bent element comprises an elongated meanderline transmission line further comprising at least two interconnected areas parallel to the top plate. 30. The method of claim 29, The antenna is mounted so as to be spaced apart from the ground plate, and the first bending element includes two elongated regions parallel to the top plate and parallel to each other in a direction parallel to the ground plate. antenna. The method of claim 29, And the antenna further comprises a feeding element. 42. The method of claim 41 wherein The feed element extends from the top plate toward the ground plate, the ground plate is disposed on a dielectric substrate, and the dielectric substrate includes a conductive feed region electrically connected to the feed element and insulated from the ground plate. An antenna, characterized in that. 30. The method of claim 29, And the second bending element faces in a direction between the sidewall and the first bending element. 30. The method of claim 29, And the side wall includes a first region disposed at a right angle with respect to the top plate, and a second region connected to the first region and disposed at a right angle with respect to the first region. An antenna connected to a spatially spaced ground plane for transmitting and receiving radio frequency energy, A conductive plate having a slot formed therein, wherein the conductive plate is divided into an inner and an outer spiral region by one or more edges, the first region of the inner and outer spiral region covering the ground plate, and the ground plate not covering the ground plate; A conductive plate comprising a second region of inner and outer spiral regions; And Sidewalls extending in a direction from the plate edge toward the ground plate when the antenna operates with the ground plate; And wherein when operating with the ground plane, the first region is disposed to face the ground plate, and wherein the second region extends beyond an edge of the ground plate. 46. The antenna of claim 45 wherein said side wall extends from said second region. 25. The antenna of claim 24 further comprising shorting means extending from said first region for electrically connecting said top plate to said ground plate. 47. The antenna of claim 46 wherein said slot defines a spiral shape.

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