KR101085814B1 - Directed dipole antenna - Google Patents

Abstract

Dual polarized variable beam tilt antenna with superior sector power ratio (SPR). The antenna may have an inclined 45 dipole radiating element comprising a director and may also be disposed on a plurality of tilted element trays to orient the antenna aiming down tilt. The director can be disposed above or near each dipole radiating element. The antenna has a beam front-to-side ratio of greater than 20 dB, a horizontal beam front-to-rear ratio of greater than 40 dB, and high roll-off and is operable over an extended frequency range.

Antenna, director, radiator, tray element, radiating element

Description

Directional Dipole Antenna {DIRECTED DIPOLE ANTENNA}

Priority claim

This application claims the benefit of US Patent Provisional Application No. 60 / 577,138, entitled "Antenna," filed June 4, 2004, of the invention filed July 3, 2003. The invention filed on December 16, 2004, claiming priority over US Provisional Application No. 60 / 484,688, entitled "Balun Antenna With Beam Director," was "optimized." Part of US Patent Application No. 10 / 737,214 entitled "Wideband Dual Polarized Base Station Antenna Offering Optimized Horizontal Beam Radiation Patterns And Variable Vertical Beam Tilt," which provides horizontal beam radiation patterns and variable vertical beam tilt. CIP) application, also filed June 26, 2003, entitled “Antenna Element, Multiband Antenna, and Method for Communicating with Multiple Devices (Antenna Element, Multiband Antenna, and Method o). f Communicating with a Plurality of Devices), filed Nov. 7, 2003, claiming priority to U.S. Provisional Application No. 60 / 482,689, entitled "antenna element, feed probe, dielectric spacer, antenna, And US Patent Application No. 10 / 703,331, entitled "Antenna Element, Feed Probe, Dielectric Spacer, Antenna and Method of Communicating with a Plurality of Devices".

TECHNICAL FIELD The present invention relates to the field of antennas, and more particularly to antennas having dipole radiating elements used in wireless communication systems.

As traffic demands on the network increase, the serviceable area expands, and new systems are installed, wireless mobile communication networks continue to evolve as they continue to be installed. A cellular type communication system has its name in that a plurality of antenna systems each serving a sector or area, commonly referred to as a cell, is implemented to achieve a serviceable area for a wider service area. Aggregated cells make up the overall service area for a particular wireless communication network.

Serving each cell is one antenna array and associated exchanges that connect the cell into the overall communication network. Typically, the antenna array is divided into sectors, where each antenna serves a respective sector. For example, three antennas of an antenna system may serve three sectors, each having a serviceable area range of about 120 °. These antennas are typically vertically polarized and are usually vertically polarized with some downtilt so that the radiation pattern of the antenna is directed slightly downward towards the mobile transceiver used by the customer. This predetermined downtilt is often a function of topographical and other geographic features. However, the optimum value of downtilt is not always predictable before actual installation and inspection. Therefore, there is always a need for custom setting of each antenna downtilt upon installation of the actual antenna. In general, high capacity cellular type systems may require re-optimization over a 24-hour period. In addition, customers want an antenna with very low intermodulation (IM) with the best gain for a given size. Therefore, the customer can indicate which antenna is best for a given network implementation.

It is still another object of the present invention to provide a dual polarized antenna having improved directivity while providing improved sector isolation while having improved directivity to realize an improved sector power ratio (SPR).

It is an object of the present invention to provide a dual polarized antenna array having an optimal horizontal plane radiation pattern. One purpose is to have radiation with at least 20 dB horizontal beam front-to-side ratio (front-side ratio), at least 40 dB horizontal beam front-to-rear ratio (front and rear ratio) and improved roll-off. To provide a pattern.

It is still another object of the present invention to provide an antenna array having an optimum orthogonal polarization performance with a minimum value of 10 dB co-pol to cross-pol ratio in a 120 ° horizontal sector.

It is another object of the present invention to provide an antenna array having a horizontal pattern beamwidth of 50 ° to 75 °.

It is still another object of the present invention to provide an antenna array having minimal intermodulation.

It is another object of the present invention to provide a dual polarized antenna array that can operate over an extended frequency range.

It is still another object of the present invention to provide a dual polarized antenna array capable of producing an adjustable vertical planar radiation pattern.

It is yet another object of the present invention to provide an antenna having improved port to port isolation of at least 30 dB.

Another object of the present invention is to provide a cheap antenna.

These and other objects of the present invention are provided by an improved antenna array for transmitting and receiving electromagnetic waves with + 45 ° and -45 ° linear polarization.

1 is a perspective view of a dual polarized antenna according to a first preferred embodiment of the present invention.

FIG. 2 is a perspective view of a multilevel ground plane structure with a portion of the tray cut away while a wideband oblique 45 orthogonal dipole radiating element is removed to show the tilting of the RF absorber and ground plane in the RF choke.

3 is a perspective view of N orthogonal shaped directors supported on a dipole radiating element.

4 is a back view of one element tray illustrating a micro strip phase shifter design used to feed each pair of orthogonal dipole radiating elements.

FIG. 5 is a rear view of a dual polarized antenna showing a cable feed network in which each micro strip phase converter is feeding one of the other dual polarized antennas.

FIG. 6 is a perspective view of a dual polarized antenna including an RF absorber that functions to perform RF radiation from a phase shifter microstripline while preventing RF current orthogonal coupling. FIG.

7 is a graph showing the high roll-off radiation pattern achieved by the present invention as compared to a typical orthogonal dipole antenna radiation pattern.

8A is a graph showing the beam pattern within a three sector site using a standard panel antenna.

 8B is a graph illustrating the beam pattern within a three sector site using a standard panel antenna.

9A is a graph illustrating the beam pattern within a three sector site using an antenna according to the present invention.

9B is a graph illustrating the beam pattern within a three sector site using an antenna according to the present invention.

10 is a perspective view of another embodiment of the present invention that includes a dual band radiating element.

FIG. 11 is a perspective view of the embodiment shown in FIG. 10 with director rings disposed over one of the radiating elements. FIG.

12 is a perspective view of an embodiment according to the invention with director rings disposed over each of the radiating elements.

13 is a diagram of various suitable structures of the director.

14 is a close-up view of a dual band antenna.

15 shows an array of dual band and single band dipole radiating elements.

Referring now to FIG. 1, a wideband dual polarized base station antenna having an optimal horizontal radiation pattern and also having a variable vertical beam tilt is shown at 10. The antenna 10 is shown such that the wideband tilt 45 orthogonal dipole (x dipole) radiating elements 14 arranged in a dipole pair 16 include a plurality of element trays 12 disposed thereon. Each of the element trays 12 is tilted in an "fallen domino" arrangement, arranged and supported by a pair of tray supports 20. The integrated element tray 12 and tray support 20 are external so that there is a laterally formed gap between the tray supports 20 and the side walls of the outer tray 22 as shown in FIGS. 1 and 2. It is fixed on and inside the tray 22. Each tray element 12 has a top surface that forms a ground plane for each dipole pair 16, and also feeds each of the dipole radiating elements 14 of the dipole pairs 16, as shown. Each air dielectric micro stripline 30 is spaced apart from each other. A plurality of electrically conductive arcuate straps 26 are secured between the side walls of the tray 22 to provide stiffness of the antenna 10 and to improve insulation between the dipole radiating elements 14.

As shown, a pair of cable supports 32 extend over each tray element 12. The supports 32 are microstrip feeds formed from the cable 76 to the air dielectric microstripline 30 and on the printed circuit board 50 attached to the bottom, as will be described in detail soon with reference to FIG. 4. Support each low intermodulation RF connection cable 34 up to the network.

Referring now to FIG. 2, the element tray 12 with one tray support 20 and a sidewall of the tray 22 partially cut away to reveal the tilted tray elements 12 configured in a “collapsed domino” arrangement. Of people. Each tray element 12 is such a "falling domino" to orient each dipole radiating element 14 pattern boresight to a preset downtilt, which may be, for example, in the middle of an array adjustable tilt range. "Are arranged in an array. In this example, the predetermined maximum beam squint level of the antenna 10 is about 4 ° of mechanical aiming, instead of about 8 ° off of mechanical aiming in the absence of tilt of the element tray 12. Matches downtilt off. In accordance with the present invention, the maximum horizontal beam perspective level is reduced to about 5 ° compared to conventional approaches, which is acceptable given the wide operating bandwidth and tilt range of the antenna.

Still referring to FIG. 2, it is shown that the tray supports 20 are separated from each adjacent sidewall of the tray 22 by a long gap forming an RF choke 36 therebetween. This choke 36 produced by the physical geometry advantageously reduces the RF current flowing on the back of the outer tray 22. The reduction of the induced current on the back of the outer tray 22 directly reduces the radiation to the rear. Important design criteria for this RF choke 36 related to maximizing radiated front-to-rear ratio include the height of the folded sidewall 38 of the outer tray 22, the height of the tray support 20, and the tray ( There is an RF choke 36 between the sidewall lip 38 of the 22 and the tray support 20. The RF choke 36 is preferably λ / 4 of the center frequency of the radiating element 14, and the RF choke 36 also has a narrow bandwidth, which is frequency dependent due to the internal reflection vanish in the air dielectric, the choke bandwidth being the center frequency. About 22% of the time.

According to another embodiment of the present invention, an RF absorber 39 may be added into the RF choke 36 such that the RF choke is less frequency dependent and thus produces a wider RF choke. The RF absorber 39 contains preferably a high percentage of carbon that slows and dissipates any RF reflected waves from causing the main beam radiation produced by the orthogonal dipole antenna 12. As shown the oblique 45 orthogonal dipole antenna 14 produces orthogonal polarized primary beam radiation in a +/- 45 ° orientation, where each beam has a horizontal component and a vertical component. Orthogonal polarization is good when these components are uniform and of equal magnitude at 360 °. In the case of the panel antenna 10 shown in FIG. 1 having a linearly arranged orthogonal dipole 14, the horizontal component of each beam orientation rolls off faster than the vertical component. This means that for each beam orientation the vertical beamwidth is wider than the horizontal beamwidth and the vertical component moves more than the horizontal component along the edge of each tray 12. Since the thin metal tray 12 has a limited surface area, the surface current thereon can less reflect the horizontal element towards the main beam radiation. Alternatively, along the edge of each tray 12, the stair cased baffles 35 must contain many vertical component vector currents. Advantageously, by adding an RF absorber 39 into the RF choke 36, the reflection of the vertical component of each beam orientation into the main beam radiation of the orthogonal dipole 14 is minimized. As a result, the orthogonal dipole 14 is not provided with a reflector at the rear.

Preferably, the element tray 12 is made of brass alloy and finished with tin plating to enable soldering. The main function of the element tray is to support the radiating element 14 in a particular orientation as shown. This orientation provides a more optimally balanced vertical and horizontal beam pattern for the two ports of the antenna 10. This orientation also provides improved insulation between each port. In addition, the element trays 12 provide an RF ground point at the coaxial cable / airstrip interface.

Tray supports are preferably made of aluminum alloy. The main function of the tray support is to support the five element trays 12 in a particular orientation that minimizes the horizontal pattern beam perspective angle.

The outer tray 22 is preferably made of a stock of aluminum alloy thicker than the urea tray 12, and is preferably alodine to prevent corrosion by external environmental conditions. Treated with a coating. The main function of the outer tray 22 is to support the inner array components. The secondary function is to focus the radiated RF output toward the front sector of the antenna 10 by minimizing the radiation towards the rear and thus maximize the radiation pattern front-to-rear ratio as described above.

Referring now to FIG. 3, one with N laterally extending parasitic broadband orthogonal dipole directors 40 disposed over the radiating element 14 and fed by the airstrip feed network 30 as shown. The radiator element 14 is shown. N is 1, 2, 3, 4 ..., and in this embodiment N is shown as 4. The laterally extending upper members of the parasitic broadband orthogonal dipole director 40 are preferably evenly spaced from each other, where the upper members have a shorter length as shown to widen the bandwidth. Unlike a Yage-Uda antenna with one reflector and spaced apart elements each generating a gain, it provides a pattern improvement while maintaining effective impedance matching so that the gain is not actually realized by the director 40. In order to properly couple the RF energy to the director, the lower members of the director 40 are spaced closer from the radiating element 14. Advantageously, an improved pattern roll-off is achieved over the 3 dB beamwidth of the radiation pattern, while maintaining a similar 3 dB beamwidth, rather than the realized gain. Preferably, the upper elements of the director 40 are spaced apart from each other by about 0.033 lambda (center frequency), while the lower director elements are spaced apart from the radiating element 14 by the parasitic 42 by about 0.025 lambda. (Λ is the wavelength of the center frequency of the radiating element 14 design).

Referring now to FIG. 4, there is shown one low loss printed circuit board (PCB) 50 with a microstrip capacitive phase shifter system shown at 52. The low loss PCB 50 is fixed to the back of each element tray 12. The micro strip capacitive phase shifter system 52 is coupled to and feeds each opposing pair of radiating elements 14 through each cable 34.

As shown in FIG. 4, each micro strip phase shifter system 52 has a phase shifter with a dielectric member 54 fixed therein that is accurately adjustable relative to the pivot point 58 by the respective transducer rod 60. A wiper arm 56. The transducer rod 60 selectively selects the phase transducer wiper arm 56 and each dielectric 54 across a pair of arcuate feedline portions 62 and 64 to adjust the phase velocity transmitted therethrough. It is adjustable in the longitudinal direction by a remote handle (not shown) to position it. Converter rod 60 is secured to PCB 50 by a pair of non-conductive standoffs 66 but spaced thereon. Low loss coaxial cable 34 is used as the primary transmission medium to provide an electrical connection between the phase converter system 52 and the radiating element 14. Gain performance is optimized by tightly adjusting the phase and amplitude distribution across the radiating element 14 of the antenna 10. The highly stable phase converter design shown in FIG. 4 achieves this control.

Referring now to FIG. 5, there is shown a back side of an antenna 10 showing a cable feed network, where each micro strip phase shifter system 52 feeds one of the other polarized antennas 14. Input 72 is referred to as port I and is the input for the -45 polarized slope and input 74 is the port II input for the +45 polarized slope. Cable 76 is a feed line coupled to one respective phase shifter system 52 as shown in FIG. The outputs of the phase shifter system 52, shown as outputs 1-5, represent the dipole pair 16 fed by each output of the phase shifter 52 system.

Referring now to FIG. 6, located beneath each of the element trays 12 and behind the antenna 10, it also functions to dissipate any backside RF radiation from the phase shifter microstrip line so that RF current is phase shifter system 52. An antenna 10 is shown that further includes an RF absorber 78 that prevents coupling between them.

Referring now to FIG. 7, compared to the standard 65 ° panel antenna with the dipole radiation pattern shown in 69, the high roll-off and front-to-off achieved by the antenna 10 according to the present invention. The rear ratio radiation pattern is shown at 68. This high roll-off radiation pattern 68 is a significant improvement over the typical dipole radiation pattern 69. The horizontal beam width is still maintained at approximately 65 ° at the 3 dB point.

In addition, the design of the radiating element 14 with the director 40 provides a significant improvement in the horizontal beam radiation pattern of the antenna, with the front-to-side level shown at 23 dB in FIG. 7. Typical orthogonal dipole radiating elements produce a horizontal beam radiating pattern with about 17 dB front-to-side ratio as shown in FIG. 7. Broadband parasitic director 40 integrated on the radiating element 14 according to the invention advantageously improves the antenna front-to-side ratio by 10 dB, shown in the example of FIG. 7 as 6 dB delta. . This improved front-to-side ratio effect is referred to as a "high roll-off" design. Unlike any conventional Yagi-Crow antenna, which has more directors and thus reduces horizontal beamwidth to have greater gain, the radiating element 14 and orthogonal dipole director 40 in this embodiment are advantageously Maintain approximately 65 ° horizontal beamwidth at 3 dB of antenna.

Referring again to FIG. 7, a good front-to-rear ratio of the antenna 10 is shown. As shown, the panel antenna 10 actually has a reduced backside lobe, thus achieving a front-to-rear ratio of about 40 dB. Furthermore, the antenna 10 has a next sector antenna / antenna isolation of about 40 dB, compared to 26 dB for a standard 65 ° panel antenna. As can also be understood in FIG. 7, with a significant reduction in the rear lobe, a 120 ° sector interference free region, provided herein as a “cone of silence”, is provided behind the spinning lobe.

Referring now to FIGS. 8A and 8B, several advantages of the present invention are shown when used within a three sector site. FIG. 8A shows a standard 65 ° flat panel antenna used in a three sector site, and FIG. 8B shows a standard 90 ° panel antenna used in a three sector site. Significant overlap of these antenna radiation patterns results in situations that require increased softer hand-offs, incomplete partitions that provide interfering signals, dropped calls, and reduced capacity.

Referring now to Figures 9A and 9B, the technical advantages of the present invention using 65 ° panel antennas and 90 ° panel antennas, respectively, used at three sector sites in accordance with the present invention are shown. Referring to Figure 9A, a significantly reduced overlap of the antenna radiation lobe is shown, thus realizing a much smaller handoff area. This results in significant call quality improvement and 5-10% site capacity improvement.

(위 식에서 P_Undesired는 상기 안테나에 의하여 제공된 섹터 외측으로 전달된 바람직하지 않은 출력을 나타내며, P_Desired는 상기 안테나에 의하여 제공된 섹터 내로 전달된 바람직한 출력을 나타낸다)Referring back to FIG. 7, the lobes of the undesired case extending beyond the 120 ° radiating sector create overlap with adjacent antenna radiation patterns as shown in FIGS. 8A and 8B and 9A and 9B. do. The undesired output delivered in the lobe outside the 120 ° front sector edge compared to the Desired case output delivered inside this 120 ° sector is referred to as the sector power ratio (SPR). Form. Advantageously the present invention achieves an SPR of less than 2%, which is defined by the following equation.

Where P _Undesired represents the undesirable output delivered outside the sector provided by the antenna and P _Desired represents the desired output delivered into the sector provided by the antenna.

delete

This SPR is a significant improvement over standard panel antennas and is one measure of the technical advantages of the present invention. The director 40 is an impedance matched at 90 ohms to the microstripline 30, and no limitation on this impedance is discussed. Radiating element 14 and quadrature dipole director 40 have mutually simultaneous electromagnetic couplings that produce with the source voltage of the matching network and the source impedance at 90 ohms. Many other system level performance advantages include such high soft handoff performance due to increased sector-to-sector rejection, reduced co-site channel interference, and increased base station system performance. Provided by the incorporation of the roll-off antenna design.

Referring now to FIG. 10, one oblique 45 orthogonal dipole radiating element and one 45 microstrip annular ring (MAR) radiator 94 surrounding the dipole, as will be discussed later with reference to FIG. 11. Another embodiment of the invention is shown to include a band dualpol antenna (80, including). In this embodiment, the antenna 80 includes N annular (ring) directors 82 disposed over the radiating element 14, where N is 1, 2, 3, 4... Although the limitation on this geometry of the director 82 is not inferred, the N directors 82 are configured as members of vertically spaced parallel polygonal shapes shown by concentric rings. Other geometric structures of the directing group can be used as shown in FIG. 13.

The ring director 82 interacts with the corresponding dipole radiating element 14 to improve the front-to-side ratio of the antenna 10 by improved roll-off. While the rising ring director 82 has a smaller circumference continuously, the ring director 82 is preferably evenly spaced above the corresponding x dipole radiating element 14. The ring directors 82 are separated by electrically nonconductive spacers, not shown, and are kept relatively close to each other, preferably spaced apart by less than 0.15 lambda (λ is the wavelength of the center frequency of the antenna design). In addition, the grouping of the ring director 82 maintains a relatively close gap between the bottom director 82 and the top of the corresponding dipole radiating element, preferably less than 0.15 lambda. There are many ways to form a set of flat directors 82, such as clips in molded form and electrically insulating.

The set of stacked ring directors 82 is also with the same circumferential rings while maintaining similar performance of the improved roll-off resulting in improved SPR with the advantages of the system described above while maintaining a similar 3 dB beamwidth. Can be done.

Referring now to FIG. 11, a dual band antenna is shown at 90 that includes a set of director rings 92 disposed over a stacked micro strip annular ring (MAR) emitter 94. In this regard, four feed probes (two balanced feed pairs) are shown arranged in pairs while feeding the double vertical polarization of the MAR emitter 94. In this embodiment of the present invention, the director 92 is a thin ring laminated over each MAR director 94 as shown. Advantageously, this dual band antenna 90 also has an improved element pattern roll-off over 3 dB beamwidth, thus increasing SPR while maintaining an equivalent 3 dB beamwidth.

Referring now to FIG. 12, a dual band antenna 100 with ring directors 82 and 92 is shown. The ring director 92 on the MAR radiator 94 is principally outward of the 3 dB beamwidth as well as improved front-to-rear radiation resulting in the above-described system advantages and improved SPR while maintaining a similar 3 dB beamwidth. It provides some additional beam geometry for the x dipole radiating element, including improved roll-off of the beam, and also interferes with the x dipole radiating element 14.

The MAR radiator element 94 and the x dipole radiating element 14 have respective ring directors thereon. The ring director 82 for the dipole radiating element 14 is also concentric with the ring director 92 for the MAR radiator 94. The advantages described above for the director can also be applied here for the frequency band (ie, front-to-rear ratio resulting in improved roll-off and improved SPR over 3 dB beamwidth).

Referring now to FIG. 13, other suitable geometries of directors 82 and 92 are shown, and the limitations on circular ring directors are not inferred. Circles are considered to be polygons with infinite sides, and the term 'polygon' is used in the appended claims.

Referring now to FIG. 14, a close-up view of a dual band antenna 80 having an orthogonal shaped director 40 extending over the radiating element 14 and a MAR director 94 having no associated annular director is shown. have.

Referring now to FIG. 15, there is shown a panel antenna 110 having an array of radiating elements 14, where each radiating element 14 has an orthogonal director 40 and the radiating elements 14 are Alternately, the MAR director 94 is disposed over the common ground plane 112. Advantages of this design include improved H-plane patterns for higher frequency radiating elements in dual band topologies. The improved H-plane pattern provides improved roll-off and improved front-to-rear ratio beyond 3 dB. The improved roll-off further provides some decoupling for the emitter depending on the number of directors incorporated due to the lower levels of side and back radiation.

Although the present invention has been described with reference to certain preferred embodiments, many variations and modifications will become apparent to those skilled in the art upon reading this specification. Therefore, it is intended that the appended claims be interpreted as broadly as possible in the context of the prior art to cover all such variations and modifications.

Claims (50)

An antenna for transmitting and receiving electromagnetic waves having + 45 ° and -45 ° linear polarization, At least one dipole radiating element 14 installed at an inclination of 45 ° on the element tray plane and provided for generating a first beam having a 3 dB beamwidth and a sector output ratio (SPR) defined as follows:

(Where P _Undesired represents undesirable output delivered outside the sector provided by the antenna and P _Desired represents the desired output delivered into the sector provided by the antenna); And At least one director (40, 82, 92) disposed proximate the dipole radiating element provided to improve the SPR of the beam while maintaining an equivalent 3 dB beamwidth; Antenna comprising a. The antenna of claim 1 wherein the antenna has a sector output ratio of 2-10%. The antenna of claim 1 wherein the antenna has a sector output ratio of 2-5%. 2. The director according to claim 1, wherein the directors (40, 82, 92) are spaced apart from the radiating element (14) at intervals of 0.01-0.15 lambda, and the lambda is the wavelength of the center frequency of the radiating element. antenna. 2. Antenna according to claim 1, characterized in that at least two directors (40, 82, 92) are provided. 6. Antenna according to claim 5, characterized in that the directors (40, 82, 92) are parallel to each other. 6. An antenna according to claim 5, wherein at least some of said directors (40, 82, 92) are uniformly spaced from each other. 8. The antenna of claim 7, wherein one of the directors is spaced closer to the radiating element than the adjacent directors. 2. Antenna according to claim 1, characterized in that the radiating element (14) is an orthogonal dipole radiating element. 10. The antenna of claim 9 wherein the director has at least two members. 11. The antenna of claim 10 wherein the members are orthogonal shaped members parallel to the orthogonal dipole radiating element in a vertical direction. The antenna of claim 1 wherein said director comprises a polygonal ring. 13. Antenna according to claim 12, characterized in that the director further comprises a plurality of polygonal shaped rings arranged on the radiating element (14). The antenna of claim 13, wherein the polygonal shaped rings are concentric. 15. The antenna of claim 14 wherein the polygonal shaped rings have a common diameter. 15. The antenna of claim 14 wherein the polygonal shaped rings have different diameters and form a tapered director. 11. The antenna of claim 10 wherein the members have different lengths and form a tapered director. 2. The antenna of claim 1 wherein the antenna has a front side ratio of at least 20 dB, wherein the front side ratio is defined as the power delivered into the sector provided by the antenna relative to the power delivered outside of the sector provided by the antenna. Characterized by an antenna. 2. The antenna of claim 1 wherein the antenna has a front and rear ratio of at least 40 dB, wherein the front and rear ratio is defined as the power delivered into the sector provided by the antenna relative to the power delivered to the rear of the sector provided by the antenna. Antenna. A plurality of tilting ground planes configured in a "fallen-domino" arrangement; And A plurality of dipole radiating elements disposed on the ground plane and forming a mechanical boresight downtilt, the down tilt being defined by an angle of radiating element relative to horizontal; Antenna comprising a. 21. The antenna of claim 20 wherein the antenna further comprises a feed network coupled to the plurality of dipole radiating elements. 22. The antenna of claim 21 wherein the aiming downtilt is formed at a center point of the overall beam downtilt. 23. The antenna of claim 22 wherein the ground planes are disposed at a fixed distance from each other. 22. The antenna of claim 21 wherein the dipole radiating elements are grouped in pairs, the pair being formed on each ground plane. A radiating element disposed on a tray having a rear surface and having a ground plane disposed above the tray; And a tray defining a gap between the side wall spaced from the ground plane. 27. The antenna of claim 25 wherein the gap forms an RF choke configured to reduce RF current flowing in the back of the tray. 27. The antenna of claim 26 further comprising an RF absorber disposed within said RF choke. 26. The antenna of claim 25 wherein the height of the sidewalls of the tray is configured to increase the front to back ratio of the antenna. 27. The antenna of claim 25 further comprising an RF absorber disposed behind the ground plane. In a dual band antenna for transmitting and receiving electromagnetic waves having + 45 ° and -45 ° linearly polarized waves, A dipole first radiating element (14) installed at an inclination of 45 ° on the tray plane and provided to generate a first beam at a first frequency; First directors 40, 82, 92 disposed proximate to the dipole radiating element provided to improve the SPR of the beam defined as follows while maintaining an equivalent 3 dB beamwidth

(Where P _Undesired represents undesirable output delivered outside the sector provided by the antenna and P _Desired represents the desired output delivered into the sector provided by the antenna); And A second radiating element (94) disposed proximate said first radiating element (14) and provided for generating a second beam at a second frequency; Dual band antenna comprising a. 31. The device of claim 30, further comprising a second director 92 disposed proximate to the second radiating element 94 provided to enhance the sector output ratio of the second beam while maintaining an equivalent 3 dB beamwidth. Dual band antenna. 32. A dual band antenna according to claim 31, wherein the first director (14) comprises at least two members. 33. The dual band antenna of claim 32, wherein the second director (92) comprises at least two members. 34. The dual band antenna of claim 33, wherein the first director 40 and the second director 92 are disposed above each of the first radiating element 14 and the second radiating element 94. . 31. The dual band antenna of claim 30, wherein the second radiating element comprises an inclined 45 micro strip annular ring radiating element. 31. The dual band antenna of claim 30, wherein the first radiating element comprises a radiator having an orthogonal shape. 31. The dual band antenna of claim 30, wherein the second radiating element comprises a polygonal radiator. 31. The dual band antenna of claim 30 wherein the first director comprises at least one orthogonal member. 32. The dual band antenna of claim 31 wherein the second director comprises at least one polygonal shaped member. 38. The dual band antenna of claim 37, wherein the first director comprises a plurality of polygonal shaped members. 32. The dual band antenna of claim 31, wherein the second director (92) comprises a plurality of polygonal shaped members. 32. A dual band antenna according to claim 30, wherein the second radiating element (94) surrounds the first radiating element (14). 43. A dual band antenna according to claim 42, wherein the first radiating element (14) comprises a dipole radiating element of orthogonal shape. 43. The dual band antenna of claim 42 wherein the second radiating element comprises a polygon. In a dual band antenna for transmitting and receiving electromagnetic waves having + 45 ° and -45 ° linearly polarized waves, A dipole radiating element 14 installed at an inclination of 45 ° on a tray plane and provided to generate a beam; Beam directing director means provided for improving the SPR of the beam defined as follows while maintaining an equivalent 3 dB beamwidth

(Where P _Undesired represents undesirable output delivered outside the sector provided by the antenna and P _Desired represents the desired output delivered into the sector provided by the antenna); Dual band antenna comprising a. 46. The dual band antenna of claim 45, wherein the director means sets a beam sector output ratio of 2-10%. 46. The dual band antenna of claim 45, wherein the director means sets a beam sector output ratio of 2-5%. 46. The dual band antenna of claim 45, wherein the director means sets a beam sector output ratio of 2%. 46. The dual band antenna of claim 45, wherein the director means sets beam front and rear ratio of at least 40 dB. 46. The dual band antenna of claim 45, wherein the director means sets beam front side ratio of at least 20 dB.

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