Patent Publication Number: US-6710742-B1

Title: Active antenna roof top system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to copending and commonly assigned U.S. patent application Ser. No. 09/456,194, entitled “Establishing Remote Beam Forming Reference Line,” filed Dec. 7, 1999, the disclosure of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     It is common in the art to utilize an antenna array comprised of a plurality of antenna elements in order to illuminate a selected area with a signal or signals. Often such an array is used in combination with beam forming techniques, such as phase shifting the signal associated with particular antenna elements of the array, such that the signals from the excited elements combine to form a desired beam, or radiation pattern, having a predetermined shape and/or direction. 
     For example beam forming matrices coupled to an antenna array, such as a phased array panel antenna, have been used in providing multiple antenna beams. One such solution utilizes a four by four Butler matrix, having four inputs to accept radio frequency signals and four outputs each of which is coupled to an antenna element or column of elements of a panel phase array antenna, to provide four antenna beams, such as four 30° directional antenna beams. Each of the antenna beams of the above phased array is associated with a particular input of the beam forming matrix such that a signal appearing at a first input of the beam forming matrix will radiate in a first antenna beam. This is accomplished by the input signal being provided to each of the four antenna elements, coupled to the outputs of the beam forming matrix, as signal components having a proper phase and/or power relation to one another. Likewise, a signal appearing at a second input of the beam forming matrix will radiate in a second antenna beam. As above, this is accomplished by the input signal being provided to each of the four antenna elements as signal components having a proper phase and/or power relation to one another which is different than the phase and/or power relation as between the signal components of the first beam. Accordingly, the beam forming matrix provides a spatial transform of the signal provided at a single input of the beam forming matrix. 
     A system such as the multiple beam system described above may be utilized to communicate signals in areas other than those of each individual antenna beam. For example, in the above described embodiment providing four 30° directional antenna beams, a signal might be simulcast from a plurality of the antenna beams to thereby communicate the signal in an area different than that associated with a single antenna beam, e.g., two antenna beams to synthesize a 60° beam or four of the antenna beams to synthesize a 120° beam. However, it should be appreciated that each of the antenna beams in the above described simulcast has a common phase center, i.e., each antenna beam sourced from the aforementioned beam forming matrix using the same antenna elements results in each such antenna beam having a common point of origin or phase center. Therefore, in order to avoid undesired destructive combining of the signal simulcast, it is desirable to present the signal to be simulcast to the beam forming inputs with a zero relative phase distribution, i.e., in the four input Butler matrix example discussed above a relative phase distribution of a signal to be simulcast on each of the four antenna beams would preferably be 0°, 0°, 0°, 0°, or each simulcast signal in phase at their respective beam forming matrix inputs. 
     Moreover, where a zero relative phase distribution is present at the beam forming inputs, beam shaping or additional beam forming control may be predictably accomplished through the use of signal amplitude or power level control. For example, to provide a desired radiation pattern a signal may be simulcast on several antenna beams with a different amplitude (whether a signal of greater or lesser magnitude) as provided to one or more of the beam forming inputs. Such systems may be utilized to provide synthesized antenna beam patterns substantially more complex than the aforementioned composite antenna beam patterns otherwise associated with a simulcast technique. 
     However, disposing signal attenuators in the antenna beam signal paths subsequent to amplification of the signal for transmission will generally result in dissipation of a portion of the power component of the signal. Achieving the power levels often required for proper signal communication, such as the power levels required of a cellular or PCS base transceiver station (BTS), is typically a very expensive proposition. Accordingly, it is not generally desired to utilize a system structure in which a portion of this power is dissipated or otherwise not actually utilized in the transmission of the signal. 
     One solution to the problem of not fully utilizing signal power for transmission of the signal might be to place the signal attenuation circuitry in the antenna beam signal paths prior to amplification of the signal for transmission. Accordingly, only a relatively small amount of signal power may be dissipated to provide a signal attenuated to a level such that, when the amplifier stage gain is added thereto, a desired relative amplitude is provided to the corresponding beam forming input. However, this solution presents its own set of problems to the communication system. Specifically, such an embodiment would typically require the removal of the amplifiers from an existing BTS system configuration in order to allow disposition of controllable attenuators in the individual signal paths prior to amplification. However, because amplification of the signals to be transmitted is often a critical function, the amplifiers may be alarmed or otherwise monitored for proper operation. This may cause substantial implementation problems when attempting to provide an applique to retrofit existing BTS systems with a smart antenna providing complex radiation pattern synthesis. 
     Accordingly, a need exists in the art for a system and method adapted to provide controlled relative power levels with respect to simulcast signals which do not result in undesired power dissipation or other substantial waste. 
     A further need exists in the art for a system and method providing controlled relative power levels with respect to simulcast signals while minimizing the impact on existing system implementations. 
     A still further need exists in the art for a system and method providing controlled relative power levels of corresponding signals having a predetermined relative phase relationship without substantially affecting such relative phase relationship. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a system and method in which signal power steering circuitry is utilized to provide controlled relative power levels with respect to a plurality of corresponding signals, such as signals to be simulcast in synthesizing a desired antenna beam. A preferred embodiment of the present invention utilizes a multiple stage circuit adapted to shift or steer signal power from a stage input between stage outputs. 
     For example, a most preferred embodiment of the present invention utilizes a matrix of back-to-back hybrid combiners, such as 90° hybrid combiners, to provide a power steering circuit. The back-to-back combiner arrangement of this embodiment provides a first hybrid combiner having a first output coupled to a first input of a second hybrid combiner and having a second output coupled to a second input of the second hybrid combiner. Preferably the back-to-back hybrid combiners have a controllable phase shifter in at least one link there between to allow control of signal power levels at the outputs of the second hybrid combiner of the back-to-back pair by selectively directing input power to the outputs of the hybrid combiner pair. 
     By coupling a plurality of such back-to-back hybrid combiner pairs into a matrix, stages of power steering may be accomplished according to the present invention. For example, where a four input beam forming matrix is utilized in providing four directional antenna beams, a two stage back-to-back hybrid combiner matrix may be utilized according to the present invention to provide desired relative power level distribution of a signal to each of the four beam forming inputs. Specifically, a first stage of the matrix may provide coarse power steering, such as between a first and second half of the beam forming inputs, and a second stage of the matrix may provide fine power steering, such as between individual beam forming inputs. 
     The preferred embodiment of the present invention is adapted to maintain, or otherwise achieve, a desired relative phase relationship of the signals provided to the beam forming inputs. For example, according to a most preferred embodiment of the present invention a zero phase relationship is maintained at the beam forming inputs. Accordingly, a preferred embodiment of the present invention includes phase control circuitry, such as disposed between one or more of the power steering stages, suitable for use in maintaining and/or providing a desired relative phase relationship. A most preferred embodiment of the present invention includes a controllable phase shifter in at least one signal path of a power steering stage to thereby control phase drift between signal paths of that particular power steering stage. 
     An advantage of the present invention is provided in that the corresponding signals relative power levels are provided through steering of the power to the appropriate signal path rather than through dissipation or other sinking of the signal power. 
     A further advantage of the present invention is that a desired relative phase relationship between the corresponding signals may be maintained. 
     A still further advantage of the present invention is provided in that preferred embodiment of the present invention may be implemented as an applique and, therefore, minimize the impact on an existing system implementation. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
     FIG. 1 shows a multiple beam antenna system which may be utilized in providing complex beam forming according to the present invention; 
     FIG. 2 shows a portion of the multiple beam antenna system of FIG. 1 adapted to provide simple antenna beam synthesization; 
     FIG. 3 shows the antenna system portion of FIG. 2 adapted to provide complex antenna beam synthesization using signal attenuation; 
     FIG. 4 shows the antenna system portion of FIG. 2 adapted to provide complex antenna beam synthesization using signal power steering techniques of a preferred embodiment of the present invention; 
     FIG. 5 shows a preferred embodiment of the power steering circuitry of FIG. 4; 
     FIGS. 6A and 6B show an alternative preferred embodiment of the power steering circuitry of FIG. 4; and 
     FIGS. 7 and 8 show alternative embodiments of signal power steering systems of the present invention scaled to accommodate independent power steering of multiple signals. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention shall be described herein with respect to a multiple beam planar antenna array in order to aid the reader in understanding the concepts of the present invention. Specifically, a preferred embodiment of the present invention shall be described with reference to a multiple beam antenna configuration providing twelve directional antenna beams, such as might be useful in providing cellular or personal communication services (PCS) wireless communications. However, it should be appreciated that the present invention is not limited in application to the specific communication system circuitry shown. Specifically, the present invention is not limited to use with respect to the antenna arrays shown and, therefore, may be utilized in arrays, whether planar or not, providing any number of antenna beams, whether fixed or adaptive beams. Moreover, the present invention is not limited to use in wireless communication systems and, therefore, may be utilized in a variety of systems in which providing power level control with respect to corresponding signals is desired. In particular, preferred embodiments of the present invention may be utilized in any system in which providing power level control with respect to corresponding signals, particularly in those systems benefitting from maintaining or providing a desired relative phase relationship. 
     Directing attention to FIG. 1, a portion of a multiple beam wireless communication system is shown generally as multiple beam antenna system  100 . Multiple beam antenna system  100  includes multiple beam planar array  101 , having antenna beams  131 - 134  associated therewith, multiple beam planar array  102 , having antenna beams  135 - 138  associated therewith, and multiple beam planar array  103 , having antenna beams  139 - 42  associated therewith. Multiple beam planar arrays  101 - 103  are disposed such that antenna beams  131 - 142  provide substantially 360° coverage about multiple beam antenna system  100 . Accordingly, multiple beam antenna system  100  is particularly well suited for use as a “smart” antenna system in a cellular or PCS communication system. 
     Each of multiple beam planar arrays  101 - 103  includes a plurality of antenna elements disposed in a predetermined configuration. Specifically, antenna elements  111 - 114 , having a predetermined spacing there between corresponding to an operational wavelength, are disposed on a face of multiple beam planar array  101 , antenna elements  115 .  118 , having a predetermined spacing there between corresponding to an operational wavelength, are disposed on a face of multiple beam planar array  102 , and antenna elements  119 - 22 , having a predetermined spacing there between corresponding to an operational wavelength, are disposed on a face of multiple beam planar array  103 . 
     In operation a signal provided to a particular input of connectors  151 - 162  will be manipulated by one of beam forming matrices  171 - 173  (such as may be Butler matrices well known in the art) to provide a proper phase progression at coupled ones of antenna elements  111 - 122  to thereby define a corresponding antenna beam of antenna beams  131 - 142 . For example, a signal applied to connector  151  will be manipulated by beam forming matrix  171  to provide a proper phase progression at each of antenna elements  111 - 114  for radiation of the signal in antenna beam  131 . 
     It should be appreciated that the antenna beams of each particular multiple beam planar array of FIG. 1 have a common phase center. For example, each of antenna beams  131 - 134  are formed utilizing an appropriate relative phase progression at antenna elements  111 - 114  and, therefore, each of antenna beams  131 - 134  has a common phase center. However, the antenna beams of the various multiple beam planar arrays of FIG. 1 have a different phase center. For example, antenna beams  131 - 134  are formed utilizing an appropriate relative phase progression at antenna elements  111 - 114  while antenna beams  135 - 138  are formed utilizing an appropriate relative phase progression at antenna elements  115 - 118 , which are separated in space from antenna elements  111 - 114 , and, therefore, each of antenna beams  131 - 134  has a different phase center than each of antenna beams  135 - 138 . 
     The above described common and different phase centers between the various antenna beams can be of significance in particular scenarios. For example, where a signal is to be communication within multiple ones of the antenna beams, such as to synthesize radiation patterns different than those of the individual antenna beam, the relationship of the phase centers of each of the beams so utilized may be of particular interest. Specifically, just as providing of a particular phase progression at the antenna elements of the antenna array may be utilized in order to provide constructive and destructive spatial combining to thereby result in a desired antenna beam, so too may this spatial combining affect signals as simulcast in multiple antenna beams. Where a signal is provided to an input associated with one antenna beam simultaneously, but offset in phase, with the signal being provided to an input associated with another antenna beam having a common phase center, the antenna beam signals may destructively combine to result in undesired nulls in the aggregate or composite synthesized antenna beam. 
     Accordingly, it may be desired to achieve and/or maintain a zero, or other predetermined, relative phase distribution with respect to one or more of the simulcast antenna beams. Specifically, where a signal is to be simulcast on antenna beams of a single antenna panel, such as multiple beam planar array  101 , a zero relative phase distribution of this signal at each of connectors  151 - 154  corresponding to the beams to be used in the simulcast may be desirable. 
     It should be appreciated that simulcasting of signals within antenna beams having different phase centers may not be as problematic as those sharing a phase center. For example, through proper antenna system configuration, these different phase centers may be disposed such that they do not present a substantial spatial destructive combining issue when signals are simulcast. Additionally or alternatively, signal manipulation techniques may be utilized to minimize the effects of simulcasting a signal with antenna beams having a different phase center, such as the introduction of delays as shown and described in copending and commonly assigned U.S. patent application Ser. No. 09/519,987, entitled “System and Method Providing Delays for CDMA Nulling,” filed Mar. 7, 2000, the disclosure of which is hereby incorporated herein by reference. 
     A preferred embodiment of the present invention shall be discussed herein with reference to the antenna beams of a single panel, such as multiple beam planar array  101 , of multiple beam antenna system  100  in order to better illustrate both the power shifting aspect of the present invention as well as the ability to maintain a desired phase progression. However, it should be appreciated that the present invention is not limited to use with respect to antenna beams of a single panel and, accordingly, may be utilized in providing power control among various antenna beams, including those associated with different panels and/or having different phase centers. 
     One way to achieve the zero relative phase distribution at the beam forming inputs described above as being desirable in synthesizing various antenna beam patterns is illustrated by the circuitry of FIG.  2 . Specifically, splitter  201  is provided such that a signal, such as a CDMA or PCS sector signal associated with a BTS transceiver, input at connector  251  is power divided and an in-phase (assuming each signal path between connector  251  and connectors  151 - 154  are of equal length), power divided, signal component is provided to each of connectors  151 - 154 . Accordingly, a zero relative phase distribution is provided at the inputs of the beam forming matrix and an aggregate antenna pattern may be provided, such as to synthesize a 120° communication sector. 
     If it is desired to produce a radiation pattern other than an aggregate of each of the four antenna beams, the simulcast signal may be removed from one or more of the beam forming inputs, such as through the use of switching devices (not shown) placed some or all of the signal paths between splitter  201  and connectors  151 - 154 . However, it should be appreciated that providing such switchable connections results in the power associated with a power divided signal component not being utilized and, therefore, dissipated or otherwise wasted. This problem is compounded in the typical case in which the signals provided to the beam former are at transmission power levels. 
     Moreover, the selection of particular antenna beams in which to simulcast a signal provides relatively simple radiation pattern synthesization, limited primarily to aggregations of the underlying antenna beam geometries. More complex radiation pattern synthesization may be provided through the use of signal amplitude or power level control. A radiation pattern very different than the aggregated antenna beams of multiple beam planar array  101  may be provided by independently adjusting the signal power level of one or more of the in-phase, power divided, signal components of the circuitry of FIG.  2 . For example, signal attenuators (not shown) may be placed in one or more of the signal paths between splitter  201  and connectors  151 - 154  to allow each signal components relative power level or signal amplitude to be individually adjusted to provide complex radiation pattern synthesization. However, this solution is not generally desirable as the signals provided to the beam former are expected to be at transmission power levels, resulting in a significant expense in wasted power. 
     An alternative solution to allow complex radiation pattern synthesization is shown in FIG.  3 . Shown in FIG. 3 is power amplifier suite  301 , comprised of a signal distribution matrix embodied as input matrix  311 , a plurality of amplifiers embodied as linear power amplifiers (LPA)  341 - 344 , and a signal combining matrix embodied as output matrix  312 . Power amplification suite  301  may be any such suit well known in the art, such as those shown and described in commonly assigned U.S. Pat. Nos. 5,955,920 and 5,917,371, the disclosures of which are hereby incorporated herein by reference. The use of a power amplifier suite may be desired in distributing the power demands of particular systems among a plurality of amplifiers. For example, CDMA signals have a high peak to average power ratio, causing such signals to be very demanding of linear power amplifier hardware for peak power handling and, therefore, may benefit from such an amplifier suite. However, alternative embodiments of the circuitry of FIG. 3 may utilize amplifiers which are unique to particular signal paths, if desired. 
     In the circuitry of FIG. 3 variable attenuators  361 - 364  are provided in the signal paths between signal input connector  355 , such as may be coupled to a BTS radio transmitter, and connectors  151 - 154  of beam former  171 . Accordingly, a signal, such as a CDMA or PCS sector signal associated with a BTS transceiver, input at connector  351  may be switchably coupled by switch  302  to one or more of connecters  151 - 154  (it being understood that switch  302  of this embodiment provides signal power splitting functionality in addition to switch matrix functionality) and independently power level adjusted by variable attenuators  361 - 364 . 
     In contrast to the alternative embodiment of the circuitry of FIG. 2 described above, however, the variable attenuators of FIG. 3 are disposed in the signal path prior to the amplification of the signals to transmission power levels. Accordingly, the dissipation of signal power is significantly lower in the circuitry of FIG. 3 than would be expected in the alternative embodiment of FIG. 2 described above. 
     Although presenting an improvement in allowing complex radiation pattern synthesis, including selection of antenna beams for use in aggregate using switch  302  and providing independent power level control using variable attenuators  361 - 364 , the circuitry of FIG. 3 may not always provide a desirable solution. For example, the circuitry of FIG. 3 presents substantial problems in implementing the circuitry as an applique to existing BTS systems. Specifically, the circuitry of FIG. 3 may require removal of amplifiers from the signal paths internal to the BTS in order to provide for signal splitting, signal switching, and/or signal attenuation, prior to the amplification of the signals. However, as the amplification of signals to transmit power levels is generally a critical function of the BTS, such removal or reconfiguring may require substantial alarm and/or monitoring reconfiguration. 
     Accordingly, the preferred embodiment of the present invention provides  9  circuitry for providing independent signal amplitude or power level adjustment without requiring substantial power dissipation and without requiring substantial alteration or reconfiguration of other communication circuitry. Moreover, preferred embodiments of the present invention provide signal amplitude or power level adjustment while maintaining or otherwise providing desired relative signal phase relationships in addition to the above described advantages. 
     Directing attention to FIG. 4, a high level block diagram of a preferred embodiment of the present invention is shown generally as system  400 . As shown in FIG. 4, the preferred embodiment includes power steerer  401  coupled between communications equipment, such as transmit radio  490 , and beam forming matrix  171  using connectors  151 - 154  and  451 . The signals manipulated by power steerer  401  may be at any power level desired, such as the aforementioned transmit power levels. Accordingly, the embodiment of FIG. 4 shows amplifier  491  disposed in the signal path before power steerer  401 . It should be appreciated that, although shown as a single amplifier, amplifier  491  may be comprised of various components, such as the amplifier suite discussed above with reference to FIG.  3 . 
     Also shown in the preferred embodiment of FIG. 4 is controller  402  coupled to power steerer  401 . Preferably, controller [ 401 ]  402  is operable to provide control signals to power steerer  401  to result in the desired steering of power of a signal input at connector  451  as output at ones of connectors  151 - 154 . Controller  402  may also be coupled to other system components, such as transmit radio  490 , in order to be provided information useful in effecting the above described power steering and/or to provide such components information with respect to the power steering of particular signals. For example, controller  402  may receive information with respect to when a signal is active at transmit radio  490  in order to provide steering signals and thereby form a desired radiation pattern with respect to that signal. Additionally or alternatively, controller  402  may receive information from a scan receiver, or other device in the receive link, providing information with respect to any or all of a position, a direction, an angle of arrival, a distance, or like communication tactical information in order to determine and/or accomplish a desired power steering solution. 
     Controller  402  of the present invention may be provided by a processor-based system operable under control of an instruction set defining operation as described herein. For example, controller  402  may be a general purpose processor-based system, such as may comprise an INTEL PENTIUM class processor platform, MOTOROLA 680×0 or POWERPC processor platforms or the like, including memory, such as RAM, hard disk storage, and/or the like, operator input/output, such as a keyboard, pointing device, display monitor, and/or the like, and data input/output, such as a network interface, serial interface, parallel interface, peripheral interface, proprietary data interface, and/or the like. 
     Alternative preferred embodiments of circuitry suitable for providing power steering of power steerer  401  are shown in FIGS. 5,  6 A and  6 B. Specifically, FIG. 5 shows an electromechanical switch implementation of a preferred embodiment of the circuitry while FIGS. 6A and 6B show a switching diode implementation of a preferred embodiment of the circuitry. 
     Directing attention to FIG. 5, power steering circuitry  500  is shown to provide steering of signal power in a power steering matrix comprising two stages. Specifically, the first stage includes controllable power shifter  510  and the second stage includes controllable power shifters  520  and  530 . The power shifters of this embodiment are comprised of a back-to-back hybrid combiners, such as 90° hybrid combiners. Specifically, controllable power shifter  510  includes back-to-back hybrid combiners  511  and  512 , controllable power shifter  520  includes back-to-back hybrid combiners  521  and  522 , and controllable power shifter [ 520 ]  530  includes back-to-back hybrid combiners  531  and  532 . 
     It should be appreciated that the back-to-back combiner arrangement provides a first hybrid combiner having a first output coupled to a first input of a second hybrid combiner and having a second output coupled to a second input of the second hybrid combiner. Preferably the back-to-back hybrid combiners have a controllable phase shifter in at least one link there between to allow control of signal power levels at the outputs of the second hybrid combiner of the back-to-back pair by selectively directing input power to the outputs of the hybrid combiner pair. For example, controllable power shifter  510  includes phase shifter  540 , preferably comprising of switches  541  and  542 , such as may be high power terminated switches, disposed in one link between back-to-back hybrid combiners  511  and  512  to allow selection of phase adjustment. In the preferred embodiment switches  541  and  542  select different signal path segment links and, thereby, provide a selectable phase shift. Controllable power shifters  520  and  530  include phase shifters  550  and  560 , preferably comprising of high power multi-position electromechanical switches (i.e., a single pole multiple position switch), switches  551 ,  552 ,  561 , and  562  respectively, to allow selection between a range of phase changes. Switches  551 ,  552 ,  561 , and  562  may preferably be operated to allow selection of phase shifts in the range of ±25° perhaps in increments of 5° (it being appreciated that particular embodiments of the present invention may accomplish negative phase shifts through utilization of corresponding phase shifting structure on the other link between the back-to-back hybrid combiners). For example, switches  551 ,  552 ,  561 , and  562  may operate to switch various lengths of transmission line segments into and/or out of the signal path used to conduct the signal. 
     It should be appreciated that, although shown as utilizing different switching mechanisms, the stages of the present invention may utilize the same switching structure in various stages or throughout the power steering circuitry. However, in the preferred embodiment of FIG. 5, different switch mechanisms are used in the first stage in order to accommodate the higher power levels expected to be present therein (it being understood that as the signal passes through power steering circuitry  500  the power is shifted among the various signal paths often resulting in less power being handled by subsequent legs of the circuitry). Accordingly, high power single pole double throw switches are used in the first stage in the illustrated embodiment. Although not providing as large of range of phase shift selection as the switches of the second stage, the first stage of embodiment of FIG. 5 is primarily to provide for the selection of left or right amplitude bias and it is expected that many implementations will operate satisfactorily with small range of selection in this first stage. 
     The preferred embodiment power shifter  510  includes switch  513  to select bias and switches  541  and  542  to select level of bias to provide various selections of power biasing. In operation switch  513 , accepting a full power input signal, is used to select whether there is to be a left or right amplitude bias, i.e., whether the amplitude adjustment is to result in a power shift bias to the left half (antenna elements  111  and  112 ) or the right half (antenna elements  113  and  114 ) of the antenna. If a left bias is desired switch  513  switches the input signal to the left input of hybrid combiner  511 . If a right bias is desired switch  513  switches the input signal to the right input of hybrid combiner  511 . 
     The nature of the hybrid combiners utilized according to the present invention results in a portion of the signal input at either hybrid input being output at both hybrid outputs. Specifically, the 90° hybrid combiners of the present invention will operate to power split a signal input at a hybrid input such that a portion of the signal power is output in phase at the hybrid output disposed directly above the hybrid input used and another portion of the signal power is output in quadrature (90° out of phase) at the hybrid output disposed on the diagonal to the hybrid input used. Accordingly, regardless of the position of switch  513  a portion of the signal input appears at each of the outputs of hybrid combiner  511 . 
     If the signals present on the two inputs of hybrid combiner  512  are coherent and out of phase an amount corresponding to the hybrid combiner (e.g. 90°) they will combine therein to again provide a full power signal at one hybrid output. Accordingly, if hybrid combiners  511  are  512  are coupled back-to-back with no phase adjusting circuitry disposed there between, a substantially full power signal would be output at a hybrid output of hybrid combiner  512  corresponding to the hybrid input of hybrid combiner  511  used. However, by introducing a phase shift in one or both of the links between these back-to-back hybrid combiners the signal power output may be altered as the signals input to hybrid combiner  512 , although still coherent, may no longer have a phase relationship corresponding to the hybrid combiner. 
     Accordingly, switches  541  and  542  may be utilized to select/deselect a phase shift in one link between hybrid combiners  511  and  512  and thereby determine the level of amplitude bias resulting from the left or right amplitude bias selected by switch  513 . Specifically, if switch  513  selects left amplitude bias, use of switches  541  and  542  to select a phase shift will minimize the amplitude bias differential between the left and right halves of the antenna (e.g., the left half of the antenna will be provided somewhat more power than the right half of the antenna). However, if switch  513  selects left amplitude bias, use of switches  541  and  542  to deselect a phase shift will maximize the amplitude bias differential between the left and right halves of the antenna (e.g., where no phase shift is selected the antenna will be provided substantially all signal power to the left half of the antenna). Similarly, if switch  513  selects right amplitude bias, use of switches  541  and  542  to select a phase shift will minimize the amplitude bias differential between the right and left halves of the antenna (e.g., the right half of the antenna will be provided somewhat more power than the left half of the antenna). However, if switch  513  selects right amplitude bias, use of switches  541  and  542  to deselect a phase shift will maximize the amplitude bias differential between the right and left halves of the antenna (e.g., where no phase shift is selected the antenna will be provided substantially all signal power to the right half of the antenna). 
     Having described in detail the operation of power shifter  510  of the first stage of power steering circuitry  500 , it should be appreciated that operation of power shifters  520  and  530  of the second stage of power steering circuitry  500  operate in substantially the same way. However, in the embodiment of FIG. 5, the power input to each of power shifters  520  and  530  is shifted between the antenna elements of the respective halves of the antenna. Of course, the circuitry of FIG. 5 may be scaled to provide additional stages, if desired, such that the second stage shifts power between subgroups of the final outputs of power steering circuitry  500  and a subsequent stage provides the granularity to shift power between these final outputs. 
     Power shifters  520  and  530  of the illustrated embodiment are configured somewhat differently than power shifter  510  described above. Specifically, power shifters  520  and  530  of the illustrated embodiment utilize a single hybrid input of hybrid combiners  521  and  531  respectively. Although a switching arrangement such as switch  513  of power shifter  510  might be employed in either or both of power shifters  520  and  530 , the preferred embodiment does not utilize such a switch and, instead, relies upon the phase shifters, phase shifters  551 ,  552 ,  561 , and  562 , disposed between back-to-back hybrid combiners  521  and  522  and back-to-back hybrid combiners  531  and  532  respectively. Specifically, the preferred embodiment phase shifters  551 ,  552 ,  561 , and  562  provide sufficient phase adjustment freedom and/or resolution to allow for their operation to satisfactorily select both the side (i.e., left or right) and level of amplitude bias between the outputs of power shifters  520  and  530 . 
     It should be appreciated that the independent adjustment of power shifters  520  and  530  according to the present invention to provide signals of desired amplitudes to each of connectors  551 - 554  can result in phase drift or a phase differential between the signals associated with power shifter  520  relative to the signals associated with power shifter  530 . Accordingly, the preferred embodiment includes phase shift compensator  570 . In the illustrated embodiment phase shift compensator  570  includes switches  571  and  572 . Preferably switches  571  and  572  are high power multi-position electromechanical switches, similar to switches  551 ,  552 ,  561 , and  562  described above, to allow selection between a range of phase changes, such as to allow selection of phase shifts in the range of ±25° perhaps in increments of 5° (it being appreciated that particular embodiments of the present invention may accomplish negative phase shifts through utilization of corresponding phase shifting structure on the other link of the second stage). For example, switches  571  and  572  may operate to switch various lengths of transmission line segments into and/or out of the signal path used to conduct the signal. 
     Although not shown, the preferred embodiment power steering circuitry  500  includes control signal links from a controller, such as controller  402  of FIG. 4, to provide dynamic operational control of particular components thereof. For example, controller  402  may be coupled to any or all of power shifters  510 ,  520 , and  530  and/or phase shift compensator  570  in order to provide control of switches therein. Accordingly, controller  402  may provide a desired signal amplitude relationship at each of connectors  515 - 154  to result in the complex synthesization of a desired radiation pattern. 
     It is expected that a typical implementation of electromechanical switches such as shown in FIG. 5 will require an appreciable amount of time, such as approximately 20 milliseconds, in order to accomplish a switching operation. Although a relatively short span of time, it may correspond to a significant portion data communicated, such as a full frame of data in a high speed digital system, such as a CDMA or TDMA system. Accordingly, it may be desired to provide circuitry which is adapted to accomplish a switching operation more quickly. For example, FIGS. 6A and 6B provide power steering circuitry  600  configured substantially the same as that of power steering circuitry  500  of FIG. 5 except switching is accomplished using switching diodes. The switching diodes of the embodiment of FIGS. 6A and 6B are expected to accomplish a switching operation appreciably quicker than the electromechanical switches of FIG. 5, such as an order of magnitude more quickly than that of the typical electromechanical switches. Accordingly, switching operations associated with the circuitry of FIGS. 6A and 6B may be expected to correspond to a lesser portion of data communicated, such as symbols rather than frames of data in a high speed digital system. 
     In the embodiment of FIGS. 6A and 6B, it should be appreciated that power steering circuitry  600  provides steering of signal power in a power steering matrix comprising two stages substantially corresponding to the stages of FIG.  5 . Accordingly, the first stage includes controllable power shifter  610  and the second stage includes controllable power shifters  620  and  630 . As with the power shifters of the embodiment of FIG. 5, the power shifters of this embodiment are comprised of a back-to-back hybrid combiners, such as  900  hybrid combiners. Specifically, controllable power shifter  610  includes back-to-back hybrid combiners  611  and  612 , controllable power shifter  620  includes back-to-back hybrid combiners  621  and  622 , and controllable power shifter  620  includes back-to-back hybrid combiners  631  and  632 . 
     Controllable power shifter  610  includes phase shifter  640 , such as may be comprised of a plurality of switchable diodes, disposed in one link between back-to-back hybrid combiners  611  and  612  to allow selection between a range of phase changes. Similarly, controllable power shifters  620  and  630  include phase shifters  650  and  660 , such as may be comprised of a plurality of switchable diodes, to allow selection between a range of phase changes. For example, phase shifters  640 ,  650  and  650  may be operated to bias various ones of the diodes, and thereby “switch” their associated phase change in or out of the signal path to allow selection of phase shifts in the range of ±25° perhaps in increments of 5° (it being appreciated that particular embodiments of the present invention may accomplish negative phase shifts through utilization of corresponding phase shifting structure on the other link between the back-to-back hybrid combiners). For example, the diodes of phase shifters  640 ,  650 , and  660  may operate to switch (e.g., providing an electronic version of a single pole multiple throw switch) various lengths of transmission line segments into and/or out of the signal path used to conduct the signal. Accordingly, phase shifters  640 ,  650 , and  660  may be utilized to select/deselect a phase shift (perhaps through a combination of the available phase adjusting components) in one link between the back-to-back hybrid combiners of a power shifter. 
     The preferred embodiment power shifters  610 ,  620 , and  630  include switches  613 ,  680 , and  690  respectively to select a desired bias, substantially as described above with respect to switch  513 . Operating in combination with a corresponding one of phase shifters  640 ,  650 , and  660 , power may be steered between the two outputs of output hybrid combiners  612 ,  622 , and  632 , respectively. Specifically, switches  613 ,  680 , and  690  include switching diode and loads (preferably an approximately  500  resistive load) configured such that when the diodes are properly biased to “switch” on or off in the proper combination, single pole double throw switching functionality is provided. Accordingly, each of switches  613 ,  680 , and  690  may be operated to select output bins for an associated power shifter. Embodiment  600  may also include phase shift compensators  670  and  671 . 
     In order to provide the diode switching of the preferred embodiment, particular relationships between the various components are preferably provided. For example, in order to predictably provide signals having particular phase relationships, each phase adjusting component (e.g., phase adjusting components  641 ,  642 ,  643 ,  644 , and  645 ) of each phase shifter (e.g. phase shifter  640 ) is preferably provided a same signal path length between the corresponding back-to-back hybrid combiners (e.g., hybrid combiners  611  and  613 ). Moreover, the switching diodes (e.g., switching diodes  646  and  647 ) are disposed at a position in the signal path (e.g., distance l 1  from signal ground (where appropriate) and/or distance l 2  from a next component) so as to effectively conduct and/or block transmitted signals. For example, the distances l 1  and l 2  may be predetermined fractions of the wavelength of signals to be communicated in order to minimize the introduction of reflected signals in the signal path. According to a preferred embodiment 1 1  is λ/2 (½ the communicated wavelength) and 1 2  is λ/4 (¼ the communicated wavelength). 
     It should be appreciated that the system configuration of FIG. 4, such as may utilize the circuitry of FIGS. 5,  6 A, and  6 B, provides amplitude adjustment of a signal, such as a cellular or PCS sector signal, input at connector  451  to provide a desired synthesized radiation pattern. If multiple overlapping synthesized radiation patterns are desired, such as to provide overlapping sectors of a cellular of PCS service or to provide multiple services (e.g., cellular and PCS) independently through a common antenna aperture, the system configuration is of the present invention may be scaled accordingly. 
     Directing attention to FIG. 7, a preferred embodiment of the present invention scaled to accommodate independent overlapping radiation pattern synthesization is shown generally as system  700 . Similar to the embodiment of FIG. 4, the preferred embodiment of FIG. 7 includes power steerer  701  a coupled between communications equipment, such as a transmit radio of a first service, and beam forming matrix  771   a . However, unlike the embodiment of FIG. 4, the embodiment of FIG. 7 also includes power steerer  701   b  coupled between communications equipment, such as a transmit radio of a second service, and beam forming matrix  771   b.    
     It should be appreciated that power steerers  701   a  and  701   b  may be provided utilizing circuitry such as shown in FIGS. 5,  6 A, and  6 B. The illustrated control signals provided to power steerers  701   a  and  701   b  may be provided by a controller such as controller  402  described above. Of course a separate controller may be utilized with respect to each of power steerers  701   a  and  701   b  or a common controller may be utilized therewith. 
     The preferred embodiment of FIG. 7 utilizes a cross polarized antenna, having slant right antenna elements associated with the first service and slant left antenna elements associated with the second service. Accordingly, an antenna aperture A consistent with that of FIG. 4 may be utilized to provide the dual services. It should be appreciated that the signals of each of the beam forming signal paths, i.e., the signal paths of each service, may be combined for communication via common antenna elements, such as through the use of a Wilkinson combiner. However, as these signals are expected to be out of phase with respect to each other and/or non-coherent, a substantial power loss would be expected from such combining. Accordingly, the preferred embodiment utilizes signal isolation, such as is provided by the aforementioned cross polarization of antenna elements, to avoid such a signal loss. 
     Although the illustrated embodiment shows the use of slant left and slant right polarization to isolate signals, other signal isolation techniques may be utilized. For example, other orthogonal polarizations may be utilized, such as vertical/horizontal or circular left/circular right. Additionally or alternatively signal isolation may be achieved through techniques such as time division access to shared components and the like. 
     It should be appreciated that the components shown in FIG. 7 may all be disposed up-mast, on the roof top, or at any other position where an antenna structure may be deployed. For example, container  750  may present a hermetically sealed roof top enclosure for the components therein in order to facilitate their deployment in the typically harsh environments in which antenna structure is generally deployed. 
     System  700  of FIG. 7 is configured to provide both forward link and reverse link communication. Accordingly, duplexers  721   a - 724   a  and  721   b - 724   b  are coupled to antenna elements  711   a - 714   a  and  711   b - 714   b  to isolate forward and reverse link circuitry. However, it should be appreciated that the use of duplexers for signal isolation typically results in signal power loss, such as on the order of several decibels. Accordingly, the alternative embodiment of FIG. 8 provides system  800  including antenna elements  811   a - 814   a ,  811   b - 814   b , and  831 - 834 . Antenna elements  811   a - 814   a  and  811   b - 814   b  are preferably associated with one link direction, such as the forward link associated with forward link circuitry  801 . Similarly, antenna elements  831 - 834  are preferably associated with another link direction, such as the reverse link associated with reverse link circuitry  802 . Using the separate antenna elements of FIG. 8 for the forward and reverse links eliminates the duplexers of FIG. 7 and, therefore, the signal power loss associated therewith. 
     It should be appreciated that the present invention is not limited to use with respect to antenna beams of a single panel and, accordingly, may be utilized in providing power control among various antenna beams, including those associated with different panels and/or having different phase centers. For example, the circuitry of the preferred embodiment may be sealed, such as to add an appropriate number of stages, to couple to the antenna beam inputs of multiple ones of the antenna panels. Additionally, or alternatively, the circuitry of the preferred embodiment may be scaled, such as to add a number of power steering circuits. For example, the preferred embodiment circuitry shown with reference to multiple beam planar array  101 , may be repeated to provide circuitry to couple to multiple beam planar array  102  and/or multiple beam planar array  103 . 
     It should be appreciated that the power steerers of the present invention may be utilized in combination with various other circuitry, if desired. For example, rather than the two power steerers shown in FIGS. 7 and 8, a power steerer may be utilized in combination with circuitry providing individual antenna beam signal paths, i.e., one forward link of the circuitry of FIG. 7 is configured with only a Butler Matrix as shown in the reverse links of the illustrated system. 
     Although preferred embodiments of the present invention have been described with reference to the use of various lengths of signal transmission line segments to provide phase adjustment, it should be appreciated that the present invention may utilize any number of suitable means for providing phase adjustment. For example, surface acoustic wave (SAW) devices, digital signal processing (DSP), and like devices may be utilized according to the present invention. 
     Moreover, although the preferred embodiments of the present invention have been described with reference to complex radiation pattern synthesis with respect to wireless transmission of signals, it should be appreciated that there is no limitation to the present invention being utilized in for such a purpose. For example, the concepts of the present invention may be applied in the receive signal path of a wireless communication system. Additionally or alternatively, the concepts of the present invention may be utilized in any situation where a plurality of signals require amplitude adjustment. 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.