1. Field of the Invention
The present invention relates in general to communication systems and components. More particularly, the present invention is directed to antennas for wireless networks.
2. Description of the Prior Art and Related Background Information
Base station antennas require low power consumption and high interoperability compatibility. Antennas must pass and transmit signals with minimum distortion and loss. Until recently, antennas have been passive devices, with their radiation pattern steering controlled by means of static mechanical mounts. With advances in computer networking, dynamic remote electro-mechanical control of antennas is possible. Antenna systems may be single or multi-band with at least one of the following radiation pattern parameters controlled remotely: Vertical Beam-peak Steering (“RET”—Remote electrical tilt), Azimuth Beam-peak Steering (“RAS”—Remote azimuth steering), and Azimuth Beam-peak Width (“RAB”—Remote azimuth beam-width). Such RET 110, RAS 120 and RAB 130 control are illustrated in
Systems employing RET, RAS, and RAB can already be met by existing designs, but designers struggle with hardware designs that can be flexible enough to meet industry requirements such as the AISG (“Antenna Interface Standards Group”) v1 and AISGv2 tower mounted specifications, while meeting competitive cost targets. Antennas are measured competitively for signal to noise ratio and the space they occupy on the tower (i.e., their foot-print). A smaller antenna with the same performance is much more desirable than a larger antenna due to vibration and wind loading and the limited space available. Additionally, cost competitiveness and supply chain flexibility create the demand for common re-usable parts and sub-assemblies.
Accordingly, there is a need to provide a simpler remote controlled system and method to adjust the radiation emission pattern of antennas.
In a first aspect, the present invention provides a remote controlled actuator system for adjusting a radiation emission pattern of an antenna. The system comprises a master controller providing actuator control signals for controlling antenna radiation emission patterns and two or more actuators, each actuator comprising an actuator control circuit communicating with the master controller and receiving actuator control signals, the actuator control circuit receiving actuator feedback signals including rotational position feedback signals and providing a drive signal in response to the actuator control signals and the actuator feedback signal. Each actuator further comprises a motor having a drive shaft, the motor receiving the drive signal and rotating the drive shaft based on the drive signal, a rotation sensor coupled to the drive shaft, the rotation sensor detecting a rotational position of the drive shaft and providing the rotational position feedback signals to the actuator control circuit, and an actuator gear coupled to the drive shaft. The system further comprises a mechanical coupling assembly having a mechanical input coupled to the actuator gear of at least one of the two or more actuators and a mechanical output coupled to a movable portion of an antenna, the assembly adjusting the radiation emission pattern of the antenna in response to rotation of the actuator gear of at least one of the two or more actuators.
In an embodiment, the mechanical coupling assembly may provide more than one mechanical output. The mechanical coupling assembly preferably further comprises one or more mechanical stops which limit the range of motion of the mechanical output. The remote controlled actuator system preferably further comprises a data bus connecting the actuator control circuits of the two or more actuators and the master controller, wherein the actuator control circuits and the master controller are connected in series in one embodiment. Alternatively, the actuator control circuit and the master controller are connected in parallel. Each of the actuator control circuit further preferably comprises one or more line filters for suppressing signal noise intermodulation distortion between the antenna and the actuator control circuit. Each of the actuator control circuits preferably changes operation status between an active mode and a dormant mode based on activity on a data bus connecting the actuator control circuit and the master controller. Each of the actuator control circuits preferably communicates with the master controller via a single wire interface. The mechanical coupling assembly preferably further comprises one or more coupling gears in meshing engagement and positioned perpendicular with the actuator gear of at least one of the two or more actuators, and one or more toothed racks in meshing engagement with a corresponding coupling gear, the one or more toothed racks translating in response to the rotation of the actuator gear of at least one of the two or more actuators.
The mechanical coupling assembly preferably further comprises a bracket mount plate having a shaft pin extending perpendicular from the bracket mount plate, the bracket mount plate having a curved toothed rack and forming an arc on the surface of the bracket mount plate, the curved toothed rack having a center corresponding with the center of the shaft pin, and an actuator mounting plate positioned apart and away from the bracket mount plate. The actuator mounting plate has a hole receiving the shaft pin, the actuator mounting plate pivotally coupled to the shaft pin, the actuator mounting plate securing one actuator of the two or more actuators and positioning the actuator gear of the actuator in meshing engagement with the curved toothed rack, the actuator gear of the actuator urging the actuator mounting plate to pivot about the shaft pin in response to rotation of the actuator gear.
The mechanical coupling assembly may further comprise a bracket mount plate having a shaft pin extending perpendicular from the bracket mount plate, a first plate having a first hole receiving the shaft pin and pivotally coupling the shaft pin, the first plate having a first curved slot shaped as an arc having a center corresponding with the first hole, the first curved slot having a first toothed portion along a length of the first curved slot, a second plate placed adjacent to the first plate, the second plate having a second hole receiving the shaft pin and pivotally coupling the shaft pin, the second plate having a second curved slot shaped as an arc having a center corresponding with the second hole, the second curved slot having a second toothed portion along a length of the second curved slot. One actuator of the two or more actuators is preferably coupled to the bracket mount plate and positions the actuator gear of the actuator in meshing engagement with the first and second toothed portions of the first and second plates, the actuator gear of the second actuator urging the first and second plates to pivot in opposite directions in response to rotation of the actuator gear of the actuator.
In another aspect, the present invention provides a remote controlled antenna system having an adjustable radiation emission pattern, the system comprising an antenna having first and second movable portions. The system further comprises a first actuator having a first actuator gear coupled to a first drive shaft, a bracket mount plate having a shaft pin extending perpendicular from the bracket mount plate, the bracket mount plate having a curved toothed rack and forming an arc on the surface of the bracket mount plate, the curved toothed rack having a center corresponding with the shaft pin, and an actuator mounting plate positioned apart and away from the bracket mount plate. The actuator mounting plate has an actuator mounting plate hole receiving the shaft pin, the actuator mounting pivotally coupling the shaft pin, the actuator mounting plate coupled to the first and second movable portions of the antenna, the actuator mounting plate securing the first actuator and positioning the first actuator gear in meshing engagement with the curved toothed rack, the first actuator gear urging the actuator mounting plate and the first and second movable portions of the antenna to pivot about the shaft pin in response to rotation of the first actuator gear.
In a preferred embodiment, the remote controlled antenna system preferably further comprises a second actuator having a second actuator gear coupled to a second drive shaft, the second actuator mounted on the actuator mounting plate, a first plate securing the first movable portion of the antenna and having a first hole receiving the shaft pin and pivotally coupling the shaft pin, the first plate having a first curved slot shaped as an arc having a center corresponding with the shaft pin, the first curved slot having a first toothed portion along a length of the first curved slot, a second plate placed adjacent to the first plate, the second plate securing the second movable portion of the antenna and having a second hole receiving the shaft pin and pivotally coupling the shaft pin, the second plate having a second curved slot shaped as an arc having a center corresponding with the shaft pin, the second curved slot having a second toothed portion along a length of the second curved slot. The second actuator gear is preferably positioned in meshing engagement with the first and second toothed portions of the first and second plates, the second actuator gear urging the first and second plates and the first and second portions of the antenna to pivot in opposite directions in response to rotation of the actuator gear. The system preferably further comprises a first set of radiating elements coupled to the first movable portion of the antenna, and a second set of radiating elements coupled to the second movable portion of the antenna. The first actuator preferably further comprises a first stepper motor having the first drive shaft, and a first rotation sensor coupled to the first drive shaft, the first rotation sensor detecting a rotational position of the first drive shaft and providing first rotational position feedback signals. The second actuator preferably further comprises a second stepper motor having the second drive shaft, and a second rotation sensor coupled to the second drive shaft, the second rotation sensor detecting a rotational position of the second drive shaft and providing second rotational position feedback signals.
In another aspect, the present invention provides a method of adjusting a radiation emission pattern of an antenna system comprising plural actuators each actuator having a drive shaft, and a mechanical coupling assembly having a mechanical output. The method comprises providing actuator control signals to plural actuators employing a common control signal format, rotating a drive shaft of at least one actuator of the plural actuators in response to the actuator control signals, detecting a rotational position of the drive shaft and providing rotational position feedback signals, coupling to the drive shaft, providing a mechanical output to an antenna, and adjusting the radiation emission pattern of the antenna.
In a preferred embodiment, providing a mechanical output may comprise transforming the rotational motion of the drive shaft of at least one actuator to a translational motion of a phase shifting means for varying the phase of an antenna element. Providing a mechanical output may comprise transforming the rotational motion of the drive shaft of at least one actuator to a pivoting motion of an antenna. Providing a mechanical output may comprise transforming the rotational motion of the drive shaft of at least one actuator to a pivoting motion of first and second subsets of radiating elements, wherein the pivoting motion of the first subsection is opposite that of the second subsection, to provide variable beam-width of the radiation pattern of the radiating elements. The method preferably further comprises detecting a mechanical stop in the mechanical coupler.
Further features and aspects of the invention are set out in the following detailed description.
A single common actuator for systems employing RET, RAS and RAB is disclosed. RET, RAS, and RAB control utilizing the disclosed actuator may employ the teachings of U.S. Pat. No. 7,505,010 entitled “ANTENNA CONTROL SYSTEM” and U.S. Pat. No. 7,990,329 entitled “DUAL STAGGERED VERTICALLY POLARIZED VARIABLE AZIMUTH BEAM-WIDTH ANTENNA FOR WIRELESS NETWORK,” the disclosures of which are incorporated herein by reference in their entirety. Remote electrical tilt is varied when the actuator slides the phase shifter dielectrics as disclosed in U.S. Pat. No. 7,505,010 for example. Remote azimuth steering is varied when the actuator rotates the antenna center around its base as disclosed in U.S. Pat. No. 7,990,329 for example. Remote azimuth beam-width is varied when the actuator opens and closes the scissor assembly as disclosed in U.S. Pat. No. 7,990,329 for example. It shall be understood, however, that the examples illustrated in the disclosures of these patents as well as exemplary embodiments described below are non-limiting and other mechanisms for adjusting the radiation emission pattern of an antenna are contemplated in one or more embodiments.
The common purpose actuator in one or more embodiments will preferably use a stepper motor, a Hall sensor, and control circuitry protection to drive advanced antenna functions uniquely. The actuator has been designed to provide single or multiple mechanical outputs, a motor range of motion defined by the use of mechanical end stops, a flexible network design, DC line filtering of internal active electronic components to improve the antenna signal to spurious noise ratio, minimized current consumption in the actuator system, and a single wire interface used for the communication between the AISG controller and the individual actuators in the system.
Embodiments of the actuator may have single or multiple mechanical outputs as illustrated in
The motor range of motion defined by the use of mechanical end stops 228 are illustrated in
One or more embodiments provide for flexible network design. This is illustrated in
In one or more embodiments, DC line filtering of internal active electronic components may be employed to improve the antenna signal to spurious noise ratio. Exemplary circuits are illustrated in
Three exemplary embodiments illustrating DC line filtering of internal active electronic components are shown in
In one or more embodiments, current consumption is minimized in the actuator system. Actuator controllers such actuator control circuit 230 preferably self-determine periods of no activity and change their operational status from active to dormant. In dormant mode, current consumption is minimized and may be eliminated. The controller returns to active mode when activity is detected on the data bus. Minimized current consumption allows for larger systems within the power consumption limits of the AISG system specifications and antenna line device system design.
In one or more embodiments, single wire interface is used for the communication between the AISG controller and the individual actuators in the system. Fewer cables in the system minimize the spurious noise in the system.
As discussed above, one or more embodiments are directed to a single common actuator for RET, RAS, and RAB control. As shown in
As depicted in
The toothed rack 222 may be coupled to an antenna such that the translational motion of the toothed rack adjusts the radiation emission pattern of an antenna. For example, as depicted in
Beam steering control results from actuator 418 having an actuator gear 420 or pinion engaging with the curved tooth rack 414. When actuator 418 rotates the actuator gear 420, the actuator mount plate 416 pivots about the shaft pin 412 to steer the radiated emission pattern of an attached antenna.
Beam-width control results from two plates 450 and 454 each having a curved toothed slot 452 and 456 which engage with the actuator gear 458 from actuator 460. When actuator 460 rotates the actuator gear 458, the two plates 450 and 454 pivot in opposite directions about the shaft pin 412 to adjust the beam-width of the radiated emission pattern of an attached antenna.
More specifically with respect to the beam steering function,
More specifically with respect to the beam-width control function,
A second plate 450 is placed adjacent to the first plate 454. The second plate 450 has a second hole 451 which receives the shaft pin 412 and pivotally couples to the shaft pin 412. The second plate 450 has a second curved slot 452 shaped as an arc having a center corresponding with the shaft pin 412. The second curved slot 452 has a second toothed portion 453 along a length of the second curved slot 452. The second toothed portion 453 may be proximal or distal to the shaft pin 412.
Actuator 460 is coupled to the actuator mount plate 416 and positions the actuator gear 458 in meshing engagement with the first and second toothed portions 457 and 453 of the first and second plates 454 and 450. The actuator gear 458 urges the first and second plates 454 and 450 to pivot in opposite directions in response to rotation of the actuator gear 458. In an embodiment and as depicted in
The present invention has been described primarily as methods and structures for remote control of the radiation emission pattern antenna systems. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Accordingly, variants and modifications consistent with the following teachings, skill, and knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain modes known for practicing the invention disclosed herewith and to enable others skilled in the art to utilize the invention in equivalent, or alternative embodiments and with various modifications considered necessary by the particular application(s) or use(s) of the present invention.
The present application claims priority under 35 U.S.C. Section 119(e) to U.S. Provisional Patent Application Ser. No. 61/559,496 filed Nov. 14, 2011, the disclosure of which is incorporated herein by reference in its entirety.
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