CN211879607U

CN211879607U - Multi-band antenna, radiating element assembly and parasitic element assembly

Info

Publication number: CN211879607U
Application number: CN202020384835.2U
Authority: CN
Inventors: 陈长富; 吴润苗
Original assignee: Commscope Technologies LLC
Current assignee: Commscope Technologies LLC
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2020-11-06
Anticipated expiration: 2030-03-24

Abstract

The utility model relates to a multiband antenna, include: a first radiating element configured to emit electromagnetic radiation within a first frequency band; a second radiating element configured to emit electromagnetic radiation within a second frequency band; and a director associated with the first radiating element configured to be substantially invisible to electromagnetic radiation within at least a portion of the second frequency band. The present invention also relates to a radiating element assembly and a parasitic element assembly.

Description

Multi-band antenna, radiating element assembly and parasitic element assembly

Technical Field

The present invention relates to communication systems, and more particularly, to a multiband antenna, a radiating element assembly, and a parasitic element assembly suitable for a communication system.

Background

A director refers to a known device mounted adjacent to a radiating element to tune the radiation pattern of the radiating element (e.g., to tune the lobe width of the radiation pattern) and/or to improve the return loss of the radiating element. The size and shape of the directors affects the frequency band in which they operate, and therefore, the size and shape of the directors need to be adjusted according to the operating frequency of the radiating element for which they are intended. The distance between the director and the radiating element it is directed towards also affects its tuning of the radiation pattern, and it may therefore also be necessary to adjust the distance between the director and the radiating element it is acting upon according to the desired radiation pattern.

Disclosure of Invention

It is an object of the present invention to provide a multi-band antenna, a radiating element assembly and a parasitic element assembly suitable for a communication system.

According to a first aspect of the present invention, there is provided a multiband antenna comprising: a first radiating element configured to emit electromagnetic radiation within a first frequency band; a second radiating element configured to emit electromagnetic radiation within a second frequency band; and a director associated with the first radiating element configured to be substantially invisible to electromagnetic radiation within at least a portion of the second frequency band.

According to a second aspect of the present invention, there is provided a multiband antenna comprising: a first array of radiating elements comprising a plurality of first radiating elements, the first array of radiating elements configured to generate a first antenna beam within a first frequency band; a second array of radiating elements comprising a plurality of second radiating elements configured to generate a second antenna beam within a second frequency band; and a parasitic element array comprising a plurality of parasitic elements for the plurality of first radiating elements, respectively, wherein each of the plurality of parasitic elements is configured to have frequency selective characteristics such that the parasitic element array tunes the first antenna beam and is substantially invisible to the second antenna beam.

According to a third aspect of the present invention, there is provided a radiating element assembly comprising: a radiating element; and a director for the radiating element, the director comprising a first inductive element and a first capacitive element.

According to a fourth aspect of the present invention, there is provided a radiating element assembly configured to receive an input signal and emit first electromagnetic radiation in a first frequency band, comprising: a radiating element configured to receive the input signal and emit a first radiation component; and a parasitic element configured to receive a first portion of the first radiation component and emit a second radiation component such that the second portion of the first radiation component and the second radiation component combine to form at least a portion of the first electromagnetic radiation, wherein the parasitic element is positioned near a direction of maximum radiation of the first radiation component and is further configured to resonate at a first frequency, thereby tuning a pattern of the first electromagnetic radiation.

According to a fifth aspect of the present invention, there is provided a parasitic element assembly positioned near a maximum radiation direction of a radiating element emitting electromagnetic radiation within a first frequency band and configured to tune a directional pattern of the electromagnetic radiation, the assembly comprising: a first inductive element configured to substantially not reduce current in the first frequency band and to reduce current in a second frequency band different from the first frequency band.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1A is a front view schematically illustrating a portion of a multi-band antenna according to one embodiment of the present invention.

Fig. 1B is a bottom view schematically illustrating a portion of the multi-band antenna of fig. 1A.

Fig. 1C is a perspective view schematically illustrating a portion of the multiband antenna of fig. 1A.

Fig. 1D is a front view schematically illustrating one of the directors included in the multiband antenna of fig. 1A.

Fig. 2A to 2F are front views schematically showing a director according to an embodiment of the present invention.

Fig. 3A to 3D are front views schematically showing a director according to an embodiment of the present invention.

Fig. 4A and 4B are front views schematically illustrating the relative positions of the directors and the radiating elements according to an embodiment of the present invention.

Fig. 5 is a perspective view schematically showing a known director and a radiating element in the prior art.

Fig. 6 is a front view schematically illustrating a director according to one embodiment of the present invention.

Fig. 7A is a graph schematically illustrating the intensity of electromagnetic radiation as a function of azimuth for: (1) one of the arrays of radiating elements in the multi-band antenna of fig. 1A, and (2) replacing the director 140 with the conventional director shown in fig. 5.

Fig. 7B is a graph schematically illustrating the intensity of electromagnetic radiation as a function of azimuth for: (1) one of the arrays of radiating elements in the multi-band antenna of fig. 1A, and (2) replacing the director 140 with the conventional director shown in fig. 5.

Note that in the embodiments described below, the same reference numerals are used in common between different drawings to denote the same portions or portions having the same functions, and a repetitive description thereof will be omitted. In some cases, similar reference numbers and letters are used to denote similar items, and thus, once an item is defined in one figure, it need not be discussed further in subsequent figures.

For convenience of understanding, the positions, sizes, ranges, and the like of the respective structures shown in the drawings and the like do not sometimes indicate actual positions, sizes, ranges, and the like. Therefore, the present invention is not limited to the positions, dimensions, ranges, and the like disclosed in the drawings and the like.

Detailed Description

The invention will be described with reference to the accompanying drawings, which illustrate several embodiments of the invention. It should be understood, however, that the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, the embodiments described below are intended to provide a more complete disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art. It is also to be understood that the embodiments disclosed herein can be combined in various ways to provide further additional embodiments.

It is understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. All terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art unless otherwise defined. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

When an element is referred to herein as being "on," attached to, "" connected to, "coupled to," or "contacting" another element, etc., it can be directly on, attached to, connected to, coupled to or contacting the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly attached to," directly connected to, "directly coupled to," or "directly contacting" another element, there are no intervening elements present. In this context, one feature being disposed "adjacent" another feature may refer to one feature having a portion that overlaps or is above or below the adjacent feature.

In this document, reference may be made to elements or nodes or features being "connected" together. Unless expressly stated otherwise, "connected" means that one element/node/feature may be mechanically, electrically, logically, or otherwise joined to another element/node/feature in a direct or indirect manner to allow for interaction, even though the two features may not be directly connected. That is, "connected" is intended to include both direct and indirect joining of elements or other features, including joining using one or more intermediate elements.

In this document, spatial relationship terms such as "upper", "lower", "left", "right", "front", "back", "high", "low", and the like may describe one feature's relationship to another feature in the drawings. It will be understood that the terms "spatially relative" encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, features originally described as "below" other features may be described as "above" other features when the device in the figures is inverted. The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the relative spatial relationships may be interpreted accordingly.

Herein, the term "a or B" includes "a and B" and "a or B" rather than exclusively including only "a" or only "B" unless otherwise specifically stated.

In this document, the term "exemplary" means "serving as an example, instance, or illustration," and not as a "model" that is to be reproduced exactly. Any implementation exemplarily described herein is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the detailed description.

In this document, the term "substantially" is intended to encompass any minor variations due to design or manufacturing imperfections, tolerances of the devices or components, environmental influences and/or other factors. The term "substantially" also allows for differences from a perfect or ideal situation due to parasitics, noise, and other practical considerations that may exist in a practical implementation.

In addition, "first," "second," and like terms may also be used herein for reference purposes only, and thus are not intended to be limiting. For example, the terms "first," "second," and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.

It will be further understood that the terms "comprises/comprising," "includes" and/or "including," when used herein, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, and/or components, and/or groups thereof.

In a multi-band antenna, a director mounted, for example, in front of a first radiating element having a first operating band may have an effect on the radiation pattern of a second radiating element having a second operating band. A multi-band antenna according to one embodiment of the present invention includes a first radiating element configured to emit electromagnetic radiation within a first operating frequency band, a second radiating element configured to emit electromagnetic radiation within a second operating frequency band, and a director configured to shape a radiation pattern of the first radiating element. The director has frequency selective characteristics so as to be substantially invisible to electromagnetic radiation within at least a portion of the second operating frequency band. Thus, the director associated with the first radiating element may have a reduced effect on the radiation pattern of the second radiating element. Embodiments of the present invention also provide radiating element assemblies including directors having frequency selective characteristics and directors having frequency selective characteristics. In some embodiments herein, directors are also referred to as "parasitic elements" or "parasitic element assemblies.

Fig. 1A to 1D are schematic diagrams of a portion of a multi-band antenna 100 according to an embodiment of the present invention. The multi-band antenna 100 may be mounted on a raised structure for operation, such as an antenna tower, utility pole, building, water tower, etc., such that the longitudinal axis of the antenna 100 extends generally perpendicular to the ground. The antenna 100 typically includes a radome (not shown) that provides environmental protection. The multi-band antenna 100 includes a reflector 160, and the reflector 160 may include a metal surface that provides a ground plane and reflects electromagnetic radiation that reaches it such that it is redirected, e.g., propagates forward. The antenna 100 may also include additional mechanical and electrical components disposed behind the reflector 160, such as one or more of connectors, cables, phase shifters, Remote Electronic Tilt (RET) units, duplexers, and the like.

Multi-band antenna 100 also includes an array of radiating elements 110, an array of radiating elements 120, and an array of radiating elements 130 disposed on the front side of reflector 160. In the illustrated embodiment, the operating band of the radiating element 110 can be, for example, 1695-2690 MHz (hereinafter abbreviated as VB) or a sub-band thereof (e.g., 1695-2200 MHz, 2300-2690 MHz, etc.). The operating band of the radiating element 120 may be, for example, 3.1-4.2 GHz (hereinafter abbreviated as SB) or a sub-band thereof. The operating band of the radiating element 130 may be, for example, 694 to 960MHz (hereinafter abbreviated RB) or a sub-band thereof. The array of VB radiating elements 110 includes two vertically extending linear arrays that are horizontally adjacent. Depending on the way the radiating elements 110 are fed, the two linear arrays may be configured to form two separate antenna beams, or may be configured to form a single antenna beam. An array of vertically extending SB radiating elements 120 is disposed between the two linear arrays. An array of vertically extending RB radiating elements 130 is disposed between the two linear arrays, and the radiating elements 130 are staggered on either side of the vertical central axis of the array of radiating elements 130, slightly offset from that axis, to obtain an antenna beam with a narrower beamwidth in the azimuth plane.

The multi-band antenna 100 also includes

parasitic elements

150, 170 that extend forward from the reflector 160. Parasitic elements 150 are disposed outside each linear array of radiating elements 110 near both edges of reflector 160 to facilitate tuning the pattern of the antenna beam produced by the two linear arrays of radiating elements 110. Parasitic elements 170 are disposed on either side of the array of radiating elements 120 and between the array of radiating elements 120 and each linear array of radiating elements 110 in order to improve isolation between the radiating elements 120 and the radiating elements 110 and to tune the pattern of the antenna beam produced by the array of radiating elements 120.

The multi-band antenna 100 further includes a plurality of directors 140 respectively associated with the plurality of VB radiating elements 110. In the illustrated embodiment, the radiating arms of the radiating element 110 define a first plane, and the director 140 extends substantially parallel to the first plane. The middle of each director 140 may be positioned at or near the maximum radiation direction of the corresponding radiating element 110, e.g. the projection of the director 140 onto the first plane is substantially in the middle of the projection of the radiating element 110 onto the first plane to tune the radiation pattern of the radiating element 110, the return loss of the radiating element 110, etc. The distance of the director 140 from the first plane, which affects the tuning, can be adjusted as desired. In one embodiment, the distance from the director 140 to the first plane is configured to be about 1/4 of a wavelength corresponding to a center frequency of the electromagnetic radiation emitted by the radiating element 110. In another embodiment, the distance from the director 140 to the first plane is configured to be between 1/8 and 3/8 of a wavelength corresponding to a center frequency of the electromagnetic radiation emitted by the radiating element 110. Unless otherwise specified, "wavelength" herein refers to a wavelength of electromagnetic waves in vacuum or air.

The dimension of the projection of the director 140 onto the first plane, e.g., the dimension of the diagonal, is approximately 1/4 of the wavelength corresponding to the center frequency of the electromagnetic radiation emitted by the radiating element 110. If the director 140 associated with one of the radiating elements 110 in the antenna 100 is replaced with the conventional director 520 shown in fig. 5, due to the size of the director 520, approximately 1/4 of the wavelength corresponding to the center frequency of VB, may be approximately equal to 1/2 of the wavelength corresponding to at least some of the frequencies in SB (i.e., within the operating frequency band of the radiating element 120), the director 520 generates strong secondary radiation when the radiating element 120 transmits or receives electromagnetic radiation at frequencies that are a subset of the 3.1-4.2 GHz band, thereby affecting the radiation pattern of the SB radiating element 120. For RB radiating element 130, it is difficult to excite currents within the RB on director 140 due to its small size, so the influence of director 140 on the radiation pattern of radiating element 130 is small and negligible.

Each director 140 is configured to have frequency selective characteristics such that it is substantially invisible to at least a portion of the electromagnetic radiation (e.g., having a given frequency) emitted by the SB radiating elements 120, thereby reducing the effect of the director 140 on the electromagnetic radiation emitted by the radiating elements 120. As shown in fig. 1D, in the illustrated embodiment, the director 140 includes capacitive elements 141 to 144 and inductive elements 145 to 148 that form the director 140. Each of the inductive elements 145 to 148 is connected in series between an adjacent pair of the capacitive elements, and each of the capacitive elements 141 to 144 is connected in series between an adjacent pair of the inductive elements, so that an LC series resonance circuit is formed in the director 140, and the circuit is a loop. The resonant frequency of the resonant circuit may be within or outside VB. In one embodiment, the resonant frequency may be the center frequency of VB (e.g., 2.3 GHz). In one embodiment, the passband of the resonant circuit includes at least a portion of VB and does not include at least a portion of SB such that the resonant circuit can attenuate current within at least a portion of SB and not substantially attenuate current within at least a portion of VB such that the director 140 is substantially invisible to electromagnetic radiation within the at least a portion of SB. In one embodiment, the passband of the resonant circuit includes at least a portion of VB and does not include all of SB such that the resonant circuit can attenuate current within all SB and not substantially attenuate current within at least a portion of VB such that the director 140 is substantially invisible to electromagnetic radiation within all SB. The pass band of the resonant circuit as referred to herein may refer to a frequency band of the amplitude-frequency characteristic of the resonant circuit having a normalized amplitude of greater than or equal to 0.7.

Fig. 7A and 7B show the variation of the intensity of electromagnetic radiation emitted by the array of SB radiating elements 120 in antenna 100 at 3.5GHz with azimuth angle. The solid lines in each figure correspond to the case where the VB radiating element 110 is configured as the director 140 shown in fig. 1D, and the broken lines correspond to the case where the VB radiating element 110 is configured as the conventional director 520 shown in fig. 5. It can be seen that director 520 can cause distortion in the radiation pattern of the array of SB radiating elements 120. After configuring the VB radiating element 110 with the director 140 as shown in fig. 1D, the radiation pattern of the array of SB radiating elements 120 is greatly improved.

The surface current of the director is mainly distributed at the edge of the director. Thus, different shapes of directors may result in different distributions of surface currents, resulting in resonant circuits with different amplitude-frequency characteristics. In the LC series resonant circuit, the larger the number of LC circuits connected in series (for example, the number of LC circuits leading to the director 140 is 4), the steeper the amplitude-frequency characteristic curve of the resonant circuit, and the narrower the passband. The director may be shaped as desired so that the resonant circuit formed in the director has a resonant strength sufficient to tune the radiation pattern of its associated radiating element and so that at least a portion of the operating frequency band of the other radiating elements is outside its passband.

The process of designing a "stealth" director for a first radiating element having a first operating band and substantially invisible to a second radiating element having a second operating band may comprise: the method comprises the steps of determining the resonant frequency and the width of a passband of a resonant circuit formed in the director, determining the capacitance and inductance of the resonant circuit from the resonant frequency, then determining the area of the capacitive element and the length of the inductive element, and determining the number of LC circuits from the width of the passband, such that the resonant circuit formed by the connection of the capacitive element and the inductive element is substantially invisible to electromagnetic radiation within the second operating frequency band. The shape and size of each of the capacitive and inductive elements, the distance between two adjacent capacitive elements, the distance between adjacent capacitive and inductive elements, and the distance between the director and the first radiating element are then adjusted so that the director including the resonant circuit can tune the radiation pattern and return loss of the first radiating element.

Fig. 2A to 2F show front views of directors 210 to 260 (in some embodiments, these directors are described as parasitic elements or parasitic element assemblies) each having an LC series resonant circuit formed therein and the resonant circuit being a loop, according to embodiments of the present invention. The number of LC circuits included in the resonance circuits of the directors 210 to 240 is 4, the number of LC circuits of the resonance circuit of the director 250 is 2, and the number of LC circuits of the resonance circuit of the director 260 is 3. The capacitive elements may be generally configured as quadrilaterals, triangles, circles, sectors, or irregular shapes, etc. Each inductive element is connected in series between an adjacent pair of capacitive elements. The inductive element may have one or more bends to increase its electrical length in the limited space between an adjacent pair of capacitive elements. In the illustrated embodiment, the directors in which the resonant circuit is formed are quadrilateral or circular. It should be understood that the directors in which the resonant circuit is formed may be quadrilateral, triangular, circular, fan-shaped, cross-shaped, T-shaped, L-shaped, irregular, or the like.

In some embodiments, the LC series resonant circuit formed in the director may not be a loop. Fig. 3A to 3D show front views of directors 310 to 340 (in some embodiments, these directors are described as parasitic elements or parasitic element assemblies) each having an LC series resonant circuit formed therein and the resonant circuit not forming a loop, according to embodiments of the present invention. The number of LC circuits leading to the resonance circuit of the director 310 is 4, the number of LC circuits leading to the resonance circuit of the director 320 is 3, and the number of LC circuits leading to the resonance circuit of the

director

330 or 340 is 2. Each of the directors 310 to 340 includes a central capacitive element, and the inductive element in each LC circuit is connected in series between the central capacitive element and the capacitive element of the other. In the illustrated embodiment, the middle capacitive element and the remaining capacitive elements are each rectangular. It will be appreciated that in other embodiments having a non-loop resonant circuit, the middle capacitive element and/or the remaining capacitive elements may be generally configured as quadrilaterals, triangles, circles, sectors, or irregular shapes, etc. The whole of the guide may be configured substantially in a quadrangular shape, a triangular shape, a circular shape, a fan shape, a cross shape, a T shape, an L shape, an irregular shape, or the like.

In some embodiments, the director associated with the first radiating element having the first operating band and substantially invisible to the second radiating element having the second operating band includes one or more inductive elements formed therein. The inductance value of such one or more inductive elements may be configured such that it has a lower impedance in the first operating frequency band and a higher impedance in the second operating frequency band, thereby enabling a reduction of the current in the second operating frequency band without substantially reducing the current in the first operating frequency band.

Fig. 6 shows a director 600 comprising one or more inductive elements formed therein. The one or more inductive elements are configured as a grid of interconnected inductive segments. Such one or more inductive elements are formed by forming an array of holes in a conductor 610, such as a conductor plate, the portions of the conductor located around the hole 620 being inductive sections 611 to 614. The holes 620 in the hole array are arranged to have a periodicity, and in one embodiment, the number of holes 620 arranged in at least one direction (e.g., in a horizontal direction, a vertical direction, a diagonal direction, other oblique directions in the viewing angle shown in fig. 6, etc.) is greater than or equal to 3. In the embodiment shown in fig. 6, the array of holes is a substantially square array of a plurality of holes 620, wherein the number of holes 620 arranged in both the transverse and longitudinal directions is 4.

The dimension d of each aperture 620 may be substantially smaller than the wavelength corresponding to the center frequency of the first operating band of the radiating element associated with the director 600. The wavelength here may be the wavelength of the electromagnetic wave in vacuum or air, or the wavelength of the electromagnetic wave in the director 600. In one embodiment, the dimension d of the aperture 620 is less than 1/10 of the wavelength corresponding to the center frequency of the first operating band. The width w of each of the inductive sections 611 to 614 may be much smaller than the dimension d of the aperture 620, in one embodiment the width w of the inductive sections 611 to 614 is smaller than 1/10 of the dimension of the aperture 620. The dimension d of the aperture 620 as referred to herein may refer to the dimension of the aperture 620 in any direction (e.g., horizontal, vertical, diagonal, other diagonal in the perspective shown in fig. 6, etc.). The width w of the inductive sections 611 to 614 referred to herein may refer to the distance between two adjacent edges of two adjacent holes 620, and may also refer to the distance from the edge of the director 600 to the adjacent hole 620. The shape, size and arrangement of the individual holes 620 in the array of holes may be designed to adjust the length and width of each inductive section 611 to 614 such that the one or more inductive elements reduce the current in the second frequency band and not substantially reduce the current in the first frequency band.

In the illustrated embodiment, the aperture 620 is substantially square in shape. It should be understood that in other embodiments, the shape of the aperture 620 may be triangular, rectangular, other polygonal shapes, circular, elliptical, irregular, etc. In the illustrated embodiment, the array of apertures is a substantially square matrix made up of a plurality of apertures 620. It should be understood that in other embodiments, the array of apertures may be a rectangular array, a diamond array, a triangular array, a circular array, a cross-shaped array, an irregularly shaped array, or the like, comprised of a plurality of apertures 620. In the illustrated embodiment, the director 600 is generally configured as a rectangle. It should be understood that in other embodiments, the director 600 may be configured generally in other quadrilateral, triangular, circular, fan, cross, T-shaped, L-shaped, or other irregular shapes, etc.

Each director (or parasitic element, or parasitic element assembly) according to the above embodiments of the present invention may be formed of a metal plate or a printed circuit board having conductors printed on a dielectric plate.

A radiating element assembly according to an embodiment of the present invention, as shown in fig. 4A and 4B, is configured to receive an input signal and emit first electromagnetic radiation within a first frequency band. The radiating element assembly includes a radiating element 410 and a director 420 (or parasitic element, parasitic element assembly). The radiating element 410 is configured to receive an input signal and emit a first radiation component. The director 420 is configured to receive a first portion of the first radiation component and emit a second radiation component such that the second portion of the first radiation component and the second radiation component combine to form at least a portion of the first electromagnetic radiation. In one embodiment, the director 420 is positioned near a maximum radiation direction of the first radiation component and is further configured to resonate at the first frequency, thereby tuning the pattern of the first electromagnetic radiation. In one embodiment, the directors 420 are configured to be frequency selective such that the directors 420 reduce the current at a given frequency. Each director and its associated radiating element in the above described embodiments may be combined into a radiating element assembly.

The directors 420 in the radiating element assembly may be positioned at any angle relative to the radiating element 410. In the case where the radiating element is a cross-dipole radiating element 410, the angle of the diagonal of the director 420 with respect to the diagonal of the radiating element 410 may be any angle within the range of 0 to 45 degrees. A diagonal of radiating element 410 may be the connection of the tail end of one radiating arm to the tail end of another radiating arm in a dipole of radiating element 410. In the embodiment shown in fig. 4A, the diagonal of the director 420 may be aligned with the diagonal of the radiating element 410, i.e., the angle of the diagonal of the director 420 with respect to the diagonal of the radiating element 410 is about 0 degrees. In the embodiment shown in fig. 4B, the diagonal of the director 420 and the diagonal of the radiating element 410 have an angle of about 45 degrees therebetween. Other angles are also possible.

In addition, embodiments of the present disclosure may also include the following examples:

1. a multi-band antenna comprising:

a first radiating element configured to emit electromagnetic radiation within a first frequency band;

a second radiating element configured to emit electromagnetic radiation within a second frequency band; and

a director associated with the first radiating element configured to be substantially invisible to electromagnetic radiation within at least a portion of the second frequency band.

2. The antenna of claim 1, wherein the director comprises one or more inductive elements.

3. The antenna of claim 2, wherein the one or more inductive elements are configured to have a higher impedance in the at least a portion of the second frequency band and a lower impedance in at least a portion of the first frequency band.

4. The antenna of claim 1, wherein the director comprises a resonant circuit.

5. The antenna of claim 4, wherein the resonant circuit is configured to attenuate currents within the at least a portion of the second frequency band.

6. The antenna of claim 5, wherein the resonant circuit is further configured to not substantially attenuate current within at least a portion of the first frequency band.

7. The antenna of claim 4, wherein the resonant circuit comprises an inductive element and a capacitive element connected in series.

8. The antenna of claim 1, wherein the director is positioned near a maximum radiation direction of the first radiating element and is spaced from the first radiating element by a distance of 1/8 to 3/8 of a wavelength corresponding to a center frequency of the first frequency band.

9. The antenna of claim 1, wherein the radiating arm of the first radiating element defines a first plane, and wherein the director extends substantially parallel to the first plane.

10. The antenna of claim 9, wherein a size of a projection of the director on the first plane is approximately 1/4 times a wavelength corresponding to a center frequency of the first frequency band.

11. The antenna of claim 1, wherein at least one frequency in the second frequency band is about 2 times greater than at least one frequency in the first frequency band.

12. A multi-band antenna comprising:

a first array of radiating elements comprising a plurality of first radiating elements, the first array of radiating elements configured to generate a first antenna beam within a first frequency band;

a second array of radiating elements comprising a plurality of second radiating elements configured to generate a second antenna beam within a second frequency band; and

a parasitic element array comprising a plurality of parasitic elements for the plurality of first radiating elements, respectively, wherein each of the plurality of parasitic elements is configured to have frequency selective characteristics such that the parasitic element array tunes the first antenna beam and is substantially invisible to the second antenna beam.

13. The antenna of claim 12, wherein the first array of radiating elements comprises horizontally adjacent vertically extending first and second linear arrays, the second array of radiating elements being disposed between the first and second linear arrays.

14. The antenna of claim 12, wherein each of the plurality of parasitic elements is positioned near a maximum radiation direction of the corresponding first radiating element and is located a distance from the corresponding first radiating element of about 1/4 wavelengths corresponding to a center frequency of the first frequency band.

15. The antenna of claim 12, wherein at least one frequency in the second frequency band is about 2 times greater than at least one frequency in the first frequency band.

16. A radiating element assembly comprising:

a radiating element configured to emit electromagnetic radiation within a first frequency band; and

a director for the radiating element, the director comprising a first inductive element and a first capacitive element.

17. The assembly of claim 16, wherein the director is positioned in front of the radiating element such that the radiating element is positioned between the director and a reflector of a base station antenna.

18. The assembly of claim 17, wherein the first inductive element is configured to have a higher impedance at a first frequency and a lower impedance in at least a portion of the first frequency band to reduce current at the first frequency.

19. The assembly of claim 16, wherein the director comprises a resonant circuit.

20. The assembly of claim 19, wherein the resonant circuit is configured to substantially not attenuate current within at least a portion of the first frequency band and to attenuate current at the first frequency.

21. The assembly of claim 19, wherein the resonant circuit comprises the first inductive element and the first capacitive element.

22. The assembly of claim 19, wherein the resonant circuit comprises a plurality of inductive elements and a plurality of capacitive elements, wherein each inductive element is connected in series between an adjacent pair of the capacitive elements, and wherein each capacitive element is connected in series between an adjacent pair of the inductive elements to form a resonant tank.

23. The assembly of claim 16, wherein the director is positioned proximate to a maximum radiation direction of the radiating element and is spaced from the radiating element between 1/8 and 3/8 of a wavelength corresponding to a center operating frequency of the radiating element.

24. The assembly of claim 16, wherein the radiating arms of the radiating elements define a first plane, the director extending substantially parallel to the first plane.

25. The assembly of claim 24, wherein a projection of the director onto the first plane has a dimension of about 1/4 of a wavelength corresponding to a center operating frequency of the radiating element.

26. The assembly of claim 24, wherein the director is oriented such that a diagonal of the director is at an angle of 0 to 45 degrees relative to a diagonal of the radiating element.

27. A radiating element assembly configured to receive an input signal and emit first electromagnetic radiation within a first frequency band, comprising:

a radiating element configured to receive the input signal and emit a first radiation component; and

a parasitic element configured to receive a first portion of the first radiation component and emit a second radiation component such that the second portion of the first radiation component and the second radiation component combine to form at least a portion of the first electromagnetic radiation,

wherein the parasitic element is positioned near a maximum radiation direction of the first radiation component and is further configured to resonate at a first frequency, thereby tuning a pattern of the first electromagnetic radiation.

28. The component of 27, wherein the first frequency is within the first frequency band.

29. The assembly of claim 27, wherein at least a portion of a passband of the resonance is located within the first frequency band.

30. The assembly of claim 27, wherein the parasitic element is spaced from the radiating element by a distance of about 1/4 wavelengths corresponding to a center frequency of the first frequency band.

31. The assembly of claim 27, wherein the parasitic element comprises a resonant circuit formed therein formed by an inductive element and a capacitive element connected in series.

32. The assembly of claim 31, wherein the resonant circuit comprises a plurality of inductive elements and a plurality of capacitive elements, wherein each inductive element is connected in series between an adjacent pair of the capacitive elements, and wherein each capacitive element is connected in series between an adjacent pair of the inductive elements to form a resonant tank.

33. The assembly of claim 27, wherein the radiating arm of the radiating element defines a first plane substantially perpendicular to a direction of maximum radiation of the first radiation component, and wherein the parasitic element extends substantially parallel to the first plane.

34. The assembly of claim 33, wherein a projection of the parasitic element onto the first plane has a size of about 1/4 times a wavelength corresponding to a center frequency of the first frequency band.

35. The assembly of claim 27, wherein the parasitic element is oriented such that a diagonal of the director is at an angle of 0 to 45 degrees relative to a diagonal of the radiating element.

36. A parasitic element assembly positioned near a maximum radiation direction of a radiating element emitting electromagnetic radiation within a first frequency band and configured to tune a pattern of the electromagnetic radiation, the assembly comprising:

a first inductive element configured to substantially not reduce current in the first frequency band and to reduce current in a second frequency band different from the first frequency band.

37. The assembly of claim 36, wherein the first inductive element is configured as a grid formed by a plurality of inductive segments interconnected.

38. The assembly of claim 37, wherein the first inductive element is formed by forming an array of holes in the conductor, and wherein the portion of the conductor surrounding the holes is the inductive section.

39. The assembly of claim 38, wherein the size of the hole is smaller than 1/10 of the wavelength corresponding to the center frequency of the first frequency band, and the width of the inductive section is smaller than 1/10 of the size of the hole.

40. The assembly of claim 38, wherein the number of holes arranged in at least one direction in the array of holes is greater than or equal to 3.

41. The assembly of claim 36, further comprising a first capacitive element configured to be connected in series to the first inductive element to form a resonant circuit.

42. The component of 41, wherein the resonant circuit is configured to not substantially attenuate current in the first frequency band.

43. The assembly of 41, further comprising:

a second capacitive element connected in series to the first inductive element such that the first inductive element is connected in series between the first capacitive element and the second capacitive element; and

a second inductive element connected in series between the second capacitive element and the first capacitive element to form a resonant tank.

44. The assembly of claim 43, further comprising:

a third capacitive element connected in series to the second inductive element such that the second inductive element is connected in series between the second capacitive element and the third capacitive element; and

a third inductive element connected in series between the third capacitive element and the first capacitive element such that the second inductive element is connected in series between the second capacitive element and the first capacitive element via the third capacitive element and the third inductive element.

45. The assembly of claim 44, further comprising:

a fourth capacitive element connected in series to the third inductive element such that the third inductive element is connected in series between the third capacitive element and the fourth capacitive element; and

a fourth inductive element connected in series between the fourth capacitive element and the first capacitive element such that the second inductive element is connected in series between the second capacitive element and the first capacitive element via the third capacitive element, the third inductive element, the fourth capacitive element, and the fourth inductive element.

46. The assembly of 41, further comprising a middle capacitive element, wherein said first inductive element is further serially connected to said middle capacitive element such that said first inductive element is serially connected between said first capacitive element and said middle capacitive element.

47. The assembly of claim 46, further comprising:

a second capacitive element; and

a second inductive element connected in series between the second capacitive element and the middle capacitive element.

48. The assembly of claim 47, further comprising:

a third capacitive element; and

a third inductive element connected in series between the third capacitive element and the middle capacitive element.

49. The assembly of 48, further comprising:

a fourth capacitive element; and

a fourth inductive element connected in series between the fourth capacitive element and the middle capacitive element.

50. The assembly of claim 41, wherein said first capacitive element is substantially quadrilateral, triangular, circular, or sector-shaped.

51. The assembly of claim 36, wherein the assembly is substantially quadrilateral, triangular, circular, sector, cross, T-shaped, or L-shaped.

52. The assembly of claim 36, wherein the assembly extends substantially parallel to a plane defined by the radiating element.

53. The component of claim 36, wherein the component is formed from conductors printed on a dielectric sheet.

54. The assembly of claim 52, wherein a projection of the assembly onto the plane has a dimension of about 1/4 of a wavelength corresponding to a center operating frequency of the radiating element.

55. The assembly of claim 36, further positioned at a distance from the radiating element of about 1/4 times a wavelength corresponding to a center frequency of the first frequency band.

Although some specific embodiments of the present invention have been described in detail by way of illustration, it should be understood by those skilled in the art that the above illustration is only for purposes of illustration and is not intended to limit the scope of the invention. The embodiments disclosed herein may be combined in any combination without departing from the spirit and scope of the present invention. It will also be appreciated by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A multi-band antenna, comprising:

4. The antenna of claim 1, wherein the director comprises a resonant circuit.

5. The antenna defined in claim 4 wherein the resonant circuit is configured to attenuate currents within the at least a portion of the second frequency band.

9. The antenna of claim 1, wherein the radiating arm of the first radiating element defines a first plane, the director extending substantially parallel to the first plane.

10. The antenna of claim 9, wherein a size of a projection of the director onto the first plane is approximately 1/4 times a wavelength corresponding to a center frequency of the first frequency band.

12. A multi-band antenna, comprising:

14. The antenna of claim 12, wherein each of the plurality of parasitic elements is positioned near a maximum radiation direction of the corresponding first radiating element and is spaced from the corresponding first radiating element by a distance of approximately 1/4 wavelengths corresponding to a center frequency of the first frequency band.

16. A radiating element assembly, comprising:

a director for the radiating element, the director comprising a first inductive element and a first capacitive element, wherein the first inductive element is configured to have a higher impedance at a first frequency and a lower impedance within at least a portion of the first frequency band to reduce current at the first frequency.

17. The assembly of claim 16, wherein the director is positioned forward of the radiating element such that the radiating element is positioned between the director and a reflector of a base station antenna.

18. The assembly of claim 16, wherein the director comprises a resonant circuit.

19. The assembly of claim 18, wherein the resonant circuit is configured to substantially not attenuate current within at least a portion of the first frequency band and to attenuate current at the first frequency.

20. The assembly of claim 18, wherein the resonant circuit comprises the first inductive element and the first capacitive element.

21. The assembly of claim 18, wherein the resonant circuit comprises a plurality of inductive elements and a plurality of capacitive elements, wherein each inductive element is connected in series between an adjacent pair of the capacitive elements, and wherein each capacitive element is connected in series between an adjacent pair of the inductive elements to form a resonant tank.

22. The assembly of claim 16, wherein the director is positioned near a maximum radiation direction of the radiating element and is spaced from the radiating element by a distance between 1/8 and 3/8 of a wavelength corresponding to a center operating frequency of the radiating element.

23. The assembly of claim 16, wherein the radiating arms of the radiating element define a first plane, the director extending substantially parallel to the first plane.

24. The assembly of claim 23 wherein the projection of the director onto the first plane has a dimension of about 1/4 of the wavelength corresponding to the central operating frequency of the radiating element.

25. The assembly of claim 23, wherein the director is oriented such that a diagonal of the director is at an angle of 0 to 45 degrees relative to a diagonal of the radiating element.

26. A radiating element assembly configured to receive an input signal and emit first electromagnetic radiation within a first frequency band, comprising:

27. The component of claim 26, wherein the first frequency is within the first frequency band.

28. The assembly of claim 26, wherein at least a portion of a passband of the resonance is located within the first frequency band.

29. The assembly of claim 26, wherein the parasitic element is spaced from the radiating element a distance of about 1/4 wavelengths corresponding to the center frequency of the first frequency band.

30. The assembly of claim 26, wherein the parasitic element comprises a resonant circuit formed therein formed by an inductive element and a capacitive element connected in series.

31. The assembly of claim 30, wherein the resonant circuit comprises a plurality of inductive elements and a plurality of capacitive elements, wherein each inductive element is connected in series between an adjacent pair of the capacitive elements, and wherein each capacitive element is connected in series between an adjacent pair of the inductive elements to form a resonant tank.

32. The assembly of claim 26, wherein the radiating arm of the radiating element defines a first plane substantially perpendicular to a direction of maximum radiation of the first radiation component, the parasitic element extending substantially parallel to the first plane.

33. The assembly of claim 32 wherein the parasitic element has a projection onto the first plane having a size of about 1/4 wavelengths corresponding to the center frequency of the first frequency band.

34. The assembly of claim 26, wherein the parasitic element is oriented such that a diagonal of the parasitic element is at an angle of 0 to 45 degrees relative to a diagonal of the radiating element.

35. A parasitic element assembly positioned near a maximum radiation direction of a radiating element that emits electromagnetic radiation within a first frequency band and configured to tune a pattern of the electromagnetic radiation, the assembly comprising:

36. The assembly of claim 35, wherein said first inductive element is configured as a grid of a plurality of inductive segments interconnected to each other.

37. The assembly of claim 36, wherein said first inductive element is formed by providing an array of holes in the conductor, the portion of the conductor surrounding the holes being said inductive section.

38. The assembly of claim 37, wherein the size of the hole is smaller than 1/10 wavelengths corresponding to the center frequency of the first frequency band, and the width of the inductive section is smaller than 1/10 of the size of the hole.

39. The assembly of claim 37, wherein the number of holes arranged in at least one direction in the array of holes is greater than or equal to 3.

40. The assembly of claim 35, further comprising a first capacitive element configured to be connected in series to the first inductive element to form a resonant circuit.

41. The component of claim 40, wherein the resonant circuit is configured to not substantially attenuate current of the first frequency band.

42. The assembly of claim 40, further comprising:

43. The assembly of claim 42, further comprising:

44. The assembly of claim 43, further comprising:

45. The assembly of claim 40, further comprising a central capacitive element, said first inductive element further connected in series to said central capacitive element such that said first inductive element is connected in series between said first capacitive element and said central capacitive element.

46. The assembly of claim 45, further comprising:

a second capacitive element; and

47. The assembly of claim 46, further comprising:

a third capacitive element; and

48. The assembly of claim 47, further comprising:

a fourth capacitive element; and

49. The assembly of claim 40, wherein said first capacitive element is substantially quadrilateral, triangular, circular, or sector-shaped.

50. The assembly of claim 35, wherein the assembly is substantially quadrilateral, triangular, circular, sector-shaped, cross-shaped, T-shaped, or L-shaped.

51. The assembly of claim 35, wherein the assembly extends substantially parallel to a plane defined by the radiating element.

52. The component of claim 35, wherein the component is formed from conductors printed on a dielectric sheet.

53. The assembly of claim 51 wherein a projection of the assembly onto the plane has a dimension of about 1/4 of a wavelength corresponding to a center operating frequency of the radiating element.

54. The assembly of claim 35, further positioned a distance from the radiating element of about 1/4 times a wavelength corresponding to a center frequency of the first frequency band.