Patent Publication Number: US-8976067-B2

Title: Antenna module having integrated radio frequency circuitry

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/495,235, filed on Jun. 9, 2011, which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     U.S. Pat. No. 7,079,869, issued Jul. 18, 2006, and titled “COMMUNICATION SYSTEM TRANSMITTER OR RECEIVER MODULE HAVING INTEGRATED RADIO FREQUENCY CIRCUITRY DIRECTLY COUPLED TO ANTENNA ELEMENT” (also referred to here as the “&#39;869 Patent”) is hereby incorporated herein by reference. 
     The &#39;869 Patent describes a radio frequency (RF) module that comprises integrated RF circuitry comprising at least one of a transmitter and a receiver, and an antenna element operatively coupled to the integrated RF circuitry. The antenna element comprises first and second substantially co-planar portions, each of said first and second substantially co-planar portions having an inner end and an outer end. The first and second substantially co-planar portions are arranged end-to-end with their respective inner ends proximate one another. The integrated RF circuitry is disposed substantially adjacent the respective inner ends of the first and second substantially co-planar portions of the antenna element. 
     However, the configuration of this module may not be suitable for all applications. 
     SUMMARY 
     One embodiment is directed to an antenna module comprising integrated RF circuitry comprising at least one of a transmitter and a receiver. The module further comprises an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions. The integrated RF circuitry is disposed on an interior part of at least one of the first and second substantially co-planar portions. 
     Another embodiment is directed to an antenna module comprising integrated RF circuitry comprising at least one of a transmitter and a receiver. The module further comprises an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions. Each of the first and second substantially co-planar portions has a first end and a second end. The integrated RF circuitry is disposed substantially adjacent to a region of the first substantially co-planar portion of the antenna element that does not include the respective first end of the first substantially co-planar portion of the antenna element. 
     Another embodiment is directed to an antenna module comprising a radio frequency transmitter, a radio frequency receiver, and an antenna element operatively coupled to the radio frequency transmitter and radio frequency receiver. The antenna element comprises first and second substantially co-planar portions. The radio frequency transmitter is operatively coupled to the first substantially co-planar portion of the antenna element. The radio frequency receiver is operatively coupled to the second substantially co-planar portion of the antenna element. Each of the first and second substantially co-planar portions have a first end and a second end. The first and second substantially co-planar portions are arranged end-to-end with their respective first ends substantially separated from one another within the antenna module. 
     Another embodiment is directed to an antenna module comprising integrated RF circuitry comprising at least one of a transmitter and a receiver. The module further comprises an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions. Each of the first and second substantially co-planar portions has a first end and a second end. The first and second substantially co-planar portions are arranged with their respective first ends proximate one another and offset from one another. The integrated RF circuitry is disposed substantially adjacent the respective first ends of the first and second substantially co-planar portions of the antenna element. 
     Another embodiment is directed to a radio frequency (RF) module for use in a communication device of a communication system. The module comprises integrated RF circuitry comprising at least one of a transmitter and a receiver. The module further comprises an antenna element operatively coupled to the integrated RF circuitry. The antenna element comprises first and second planar portions. The first planar portion is disposed in a first plane and the second planar portion is disposed in a second plane. Each of the first and second planar portions has a respective first end and a respective second end. The first and second planar portions are arranged within the respective first and second planes end-to-end with their respective first ends proximate one another. The integrated RF circuitry is disposed substantially adjacent the respective first ends of the first and second planar portions of the antenna element. 
    
    
     
       DRAWINGS 
         FIG. 1  is a block diagram of one exemplary embodiment of an integrated antenna module. 
         FIGS. 2-4  and  15  are diagrams illustrating examples of patch antennas. 
         FIG. 5  illustrates one exemplary embodiment of an integrated antenna module with two transmit antenna portions and two receive antenna portions. 
         FIG. 6  illustrates one example of a circular patch antenna. 
         FIGS. 7-13  illustrate various embodiments of antenna elements. 
         FIG. 14  is a block diagram of one exemplary embodiment of a distributed antenna system in which integrated antenna modules can be used. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of one exemplary embodiment of an integrated antenna module  100 . The exemplary embodiment of the integrated antenna module  100  shown in  FIG. 1  communicates with a digital baseband module (not shown) using a digital baseband interface  102 . Examples of suitable digital baseband interfaces include the digital baseband interfaces specified in the Open Base Station Architecture Initiative (OBSAI) and Common Public Radio Interface (CPRI) family of standards and specifications. The digital baseband interface  102  provides an interface by which digital “transmit” baseband data  104  is provided to the antenna module  100  from the digital baseband module and by which digital “receive” baseband data  106  is provided from the antenna module  100  to the digital baseband module. In the particular exemplary embodiment described here in connection with  FIG. 1 , the digital transmit baseband data  104  comprises an in phase component  104 -I and a quadrature-phase component  104 -Q, and the digital receive baseband data  106  comprises an in-phase component  106 -I and a quadrature-phase component  106 -Q. 
     The integrated antenna unit  100  is implemented using integrated RF circuitry. The integrated RF circuitry includes a transmit path  108  (also referred to here as a “transmitter”  108 ) and a receive path  110  (also referred to here as the “receiver”  110 ). 
     The transmitter  108  includes a digital filter/calibration unit  112  that applies phase and/or amplitude changes to the digital transmit baseband data  104  received over the digital baseband interface  102 . These applied phase and/or amplitude changes are used to create a defined phase and/or amplitude relationship between various RF signals radiated from the transmit portion  114  of an antenna element  115  of multiple antenna modules  100  in an antenna array (described below) in order to perform beam forming and/or antenna steering. The digital filter/calibration unit  112  is also configured to calibrate the transmit path  108 . Calibrating the transmit path  108  involves one or more of estimating the accumulated phase and/or amplitude deviation along the transmit path  108  and the time it takes a signal to travel from the digital baseband interface  102  to the respective transmit portion  114  of the antenna element  115  (described below). The digital filter/calibration unit  112  is also configured to apply digital pre-distortion to the digital transmit baseband data  104  in order to compensate for non-linearities in the transmit path  108 . In the particular exemplary embodiment described here in connection with  FIG. 1 , the digital filter/calibration unit  112  operates on both the in-phase and quadrature components  104 -I and  104 -Q of the digital transmit baseband data  104 . The digital output of the digital filter/calibration unit  112  includes both in-phase and quadrature components. 
     In the particular exemplary embodiment described here in connection with  FIG. 1 , the transmit path  108  of the antenna module  100  also includes a digital-to-analog converter (DAC)  116  that converts the in-phase and quadrature components of the digital output of the digital filter/calibration unit  112  to respective analog baseband in-phase and quadrature signals. The transmit path  108  of the antenna module  100  also includes quadrature mixer  118  that mixes the analog baseband in-phase and quadrature signals output by the DAC  116  with appropriate quadrature mixing signals to produce the desired transmit RF signal. The quadrature mixing signals are produced in the conventional manner by an oscillator circuit  120 . The oscillator circuit  120  is configured to phase lock a local clock signal to a reference clock and to produce the mixing signals at the desired frequency. The RF transmit signal output by the quadrature mixer  118  is bandpass filtered by bandpass filter  122  and amplified by amplifier  124 . 
     The transmitter  108  is coupled to the transmit portion  114  of the antenna element  115  in order cause the RF transmit signal output by the transmitter  108  to be radiated from the transmit antenna element  114 . In the embodiment shown in  FIG. 1 , the antenna element  115  that is coupled to integrated RF circuitry (that is, the transmitter  108  and receiver  110 ) includes a transmit portion  114  and a receive portion  126 , where the transmitter  108  is coupled to the transmit portion  114  and the receiver  110  is coupled to the receive portion  126 . In general, the antenna element  115  (and the portions  114  and  126  thereof) can be configured as described in the &#39;869 Patent with the modifications and improvements described here. 
     The receiver  110  is coupled to the receive portion  126  of the antenna element  115  in order to receive an analog RF receive signal. In the particular exemplary embodiment described here in connection with  FIG. 1 , the analog RF receive signal is input to a quadrature mixer  128  that mixes the analog RF receive signal with appropriate quadrature mixing signals in order to produce analog baseband in-phase and quadrature signals. The quadrature mixing signals are produced by the oscillator circuit  120 . The analog baseband in-phase and quadrature signals output by the quadrature mixer  128  are bandpass filtered by bandpass filters  129 . 
     In the particular exemplary embodiment described here in connection with  FIG. 1 , the receiver  110  also includes an analog-to-digital converter (ADC)  130  that converts the analog baseband in-phase and quadrature signals to in-phase and quadrature digital receive baseband data, respectively. 
     The receiver  110  also includes a digital filter/calibration unit  132  that applies phase and/or amplitude changes to the digital receiver baseband data output by the ADC  130 . These applied phase and/or amplitude changes are used to create a defined phase and/or amplitude relationship between various RF signals received from the receive portion  126  of the antenna element  115  of multiple antenna modules  100  in an antenna array (described below) in order to perform beam forming and/or antenna steering. The digital filter/calibration unit  132  is also configured to calibrate the receive path  110 . Calibrating the receive path  110  involves one or more of estimating the accumulated phase and/or amplitude deviation along the receive path  110  and the time it takes a signal to travel from the respective receive portion  126  (described below) to the digital baseband interface  102 . The digital filter/calibration unit  132  is configured to apply digital post-distortion to the digital receive baseband data in order to compensate for non-linearities in the receive path  110 . In the particular exemplary embodiment described here in connection with  FIG. 1 , the digital filter/calibration unit  132  operates on both the in phase and quadrature components of the digital receive baseband data output by the ADC  130 . The digital output of the digital filter/calibration unit  132  is the digital receive baseband data  106  that is provided to the baseband module over the digital baseband interface  102 . 
     Multiple antenna modules  100  can be arranged together in order to form an antenna array that can be used to perform beam forming and/or antenna steering (for example, as described in the &#39;869 Patent). 
     Each antenna module  100  also includes a controller  134  (or other programmable processor) that is used to control the operation of the antenna module  100  and to interact with the baseband module using a control interface  136  implemented between the antenna module  100  and the baseband module. 
     In the embodiment shown in  FIG. 1 , separate transmit and receive portions  114  and  126  of the antenna element  115  are used in order to reduce the amount of filtering required between transmit path  108  and the receive path  110 . Doing so reduces the cost of the antenna module  100 . Typically, a duplexer is required between the transmit path and the receive path in a frequency division duplex (FDD) system (especially where a single antenna is used for both the transmit and receive paths) in order to prevent the transmit signals from overloading the receiver or destroying the receiver. The transmit and receive portions  114  and  126  of the antenna element  115  are arranged such that some near field signal cancellation occurs between the transmitted and received signals so that the requirements for isolation and filtering are reduced. 
     The antenna element  115  (and the transmit and receive portions  114  and  126  thereof) are typically implemented as “patch antennas”, which are a subset of the planar antenna family. These patch antennas are usually comprised of a flat plate or PC board material where the antenna element is separated from a ground plane by a substrate material and fed or “excited” by connecting the transmitted signal to either the center, off-center, or even the edge of the patch. The patch radiates energy from the edges and is in effect a “leaky cavity” with all of the effective energy emitted from the edges. Most patches are square or close to square in layout with the dimensions of a side roughly ˜wavelength/2. Significant work has been done with modified shapes and another version of the patch is a triangle with the two sides being the resonate edges. Patch antennas usually radiate in an omni-directional pattern above the surface of the plate, but this also means that the radiation pattern is only on the side of the ground plane that has the patch. The bottom side of the ground plane has virtually no radiation. Examples of patch antennas are shown in  FIGS. 2-4 . 
     Feeding such a patch antenna element can be done by applying a signal directly to the outer surface of the patch or through an opening in the ground plane (at, for example, the center, near-center, or end of the patch). One example of this latter approach is shown in  FIG. 4 . This latter approach would enable the building of circuits under the ground plane. 
     The transmitter  108  and the receiver  110  of the antenna module  100  can be coupled to the respective transmit and receive portions  114  and  126  of the antenna element  115  by directly connecting the output transmitter  108  or receiver  110  (for example, where the output of the transmitter  108  or input of the receiver  110  is positioned near the respective portion of the antenna element) or indirectly using an integrated transmission line (such as a stripline or a microstrip) to couple the output of the transmitter  108  or the input of the receiver  110  to the respective portion of the antenna element. 
     In another embodiment, the patch antenna element (and/or one or more of the portions thereof) can curve around edges to provide a desired radiation pattern. In some instances, this can help provide coverage in all directions so both the transmit and receive antenna portions cover the same area. 
     In general, the transmit and receive portions  114  and  126  of the antenna element  115  can be arranged in various ways. 
     In one exemplary embodiment, the antenna element comprises first and second substantially co-planar portions (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions, respectively) and the integrated RF circuitry (that is, the transmitter  108  and the receiver  110 ) is disposed on an interior part of at least one of the first and second substantially co-planar portions. 
     In such an exemplary embodiment, each of the first and second substantially co-planar portions of the antenna element can have a respective first end and a respective second end, wherein the first and second substantially co-planar portions are arranged end-to-end. 
     In such an exemplary embodiment, the first and second substantially co-planar portions can be arranged end-to-end with their respective first ends proximate one another. 
     In such an exemplary embodiment, the integrated RF circuitry can be disposed on an interior part of both of the first and second substantially co-planar portions. 
     In such an exemplary embodiment, the integrated RF circuitry can be completely disposed on an interior part of only the first substantially co-planar portion. The antenna module can further comprise a transmission line to operatively couple the integrated RF circuitry to the second substantially co-planar portion. One example of such an embodiment is shown in  FIG. 7 . 
     In such exemplary embodiment, the antenna module can be deployed in a distributed antenna system (for example, in the distributed antenna system described below in connection with  FIG. 14 ). 
     In another exemplary embodiment, the antenna element comprises first and second substantially co-planar portions (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions, respectively) and each of the first and second substantially co-planar portions have a first end and a second end. The integrated RF circuitry (that is, the transmitter  108  and the receiver  110 ) is disposed substantially adjacent to a region of the first substantially co-planar portion of the antenna element that does not include the respective first end of the first substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the first and second substantially co-planar portions can be arranged end-to-end. 
     In such an exemplary embodiment, the first and second substantially co-planar portions can be arranged end-to-end with their respective first ends proximate one another. 
     In such an exemplary embodiment, the integrated RF circuitry can be disposed substantially adjacent to a respective region of the second substantially co-planar portion of the antenna element that does not include the respective first end of the second substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the integrated RF circuitry can be disposed substantially adjacent to the respective second end of the first substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the antenna module can further comprise a transmission line to operatively couple the integrated RF circuitry to the first substantially co-planar portion. 
     In such an exemplary embodiment, the transmission line can operatively couple the integrated RF circuitry to the respective first end of the first substantially co-planar portion. 
     In such an exemplary embodiment, the antenna module can be deployed in a distributed antenna system (for example, in the distributed antenna system described below in connection with  FIG. 14 ). 
     In another exemplary embodiment, the antenna element comprises first and second substantially co-planar portions (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions, respectively). The radio frequency transmitter is operatively coupled to the first substantially co-planar portion of the antenna element, and the radio frequency receiver is operatively coupled to the second substantially co-planar portion of the antenna element. Each of the first and second substantially co-planar portions have a first end and a second end, and the first and second substantially co-planar portions are arranged end-to-end with their respective first ends substantially separated from one another within the antenna module. 
     In such an exemplary embodiment, the radio frequency transmitter can be disposed substantially adjacent the respective first end of the first substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the radio frequency transmitter can be directly coupled to the first substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the radio frequency transmitter can be directly coupled to the first substantially co-planar portion of the antenna element without use of a separate cable or wire. 
     In such an exemplary embodiment, the radio frequency receiver can be disposed substantially adjacent the respective first end of the second substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the radio frequency receiver can be directly coupled to the second substantially co-planar portion of the antenna element. 
     In such an exemplary embodiment, the radio frequency receiver can be directly coupled to the second substantially co-planar portion of the antenna element without the use of a separate cable or wire. 
     In such an exemplary embodiment, the antenna module can be deployed in a distributed antenna system (for example, in the distributed antenna system described below in connection with  FIG. 14 ). 
     In another exemplary embodiment, the antenna element comprises first and second substantially co-planar portions (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions, respectively) and each of the first and second substantially co-planar portions have a first end and a second end. The first and second substantially co-planar portions are arranged with their respective first ends proximate one another and offset from one another. The integrated RF circuitry (that is, the transmitter  108  and the receiver  110 ) is disposed substantially adjacent the respective first ends of the first and second substantially co-planar portions of the antenna element. 
     In such an exemplary embodiment, the antenna module can be deployed in a distributed antenna system (for example, in the distributed antenna system described below in connection with  FIG. 14 ). 
     In another exemplary embodiment, the antenna element comprising first and second planar portions (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions, respectively). The first planar portion is disposed in a first plane and the second planar portion is disposed in a second plane. Each of the first and second planar portions has a respective first end and a respective second end. The first and second planar portions are arranged within the respective first and second planes end-to-end with their respective first ends proximate one another. The integrated RF circuitry (that is, the transmitter  108  and the receiver  110 ) is disposed substantially adjacent the respective first ends of the first and second planar portions of the antenna element. 
     In such an exemplary embodiment, the antenna module can be deployed in a distributed antenna system (for example, in the distributed antenna system described below in connection with  FIG. 14 ). 
     In such an exemplary embodiment (shown in  FIG. 15 ), the antenna module can further comprise a substrate  1502  having a ground plane  1504 , where the substrate  1502  has first and second opposing surfaces  1506  and  1508  separated by the ground plane  1504 . The first plane in which the first planar portion  1510  of the antenna element is disposed can comprise the first surface  1506  of the substrate  1502 , and the second plane in which the second planar portion  1512  of the antenna element is disposed can comprise the second surface  1508  of the substrate  1502 . 
     In such an exemplary embodiment, the integrated RF circuitry can comprise first and second surfaces. The first plane in which the first planar portion of the antenna element is disposed can comprise the first surface of the RF circuitry. The second plane in which the second planar portion of the antenna element is disposed can comprise the second surface of the integrated RF circuitry. 
     Other embodiments of integrated antenna modules are possible. 
       FIG. 5  illustrates an integrated antenna module  500  with two transmit antenna portions  502  and two receive antenna portions  504 . As shown in  FIG. 5 , each of the antenna portions  502  and  504  is triangular. The two receive antenna portions  504  are arranged with tips of the respective triangles across from each other and pointing at each other. Likewise, the two transmit antenna portions  502  are arranged with tips of the respective triangles across from each other and pointing at each other. In some implementations, the antenna portions are configured so that radiation occurs off of the edges. 
     Each of the transmit antenna portions  502  is coupled to a respective integrated transmitter (for example, like the transmitter  108  described above in connection with  FIG. 1 ) (not shown in  FIG. 5 ), and each receive antenna portion  504  is coupled to a respective integrated receiver (for example, like the receiver  110  described above in connection with  FIG. 1 ) (not shown in  FIG. 5 ). 
     The embodiment shown in  FIG. 5  can be used for MIMO applications or other multiple transmitter/receiver applications such as beam forming and antenna steering. 
     Also, a similar arrangement of antenna portions can be placed on more than one side (surface) of the cube structure shown in  FIG. 5 . 
     Moreover, although the triangular antenna portion arrangement is shown in  FIG. 5  as being disposed on a cube structure, such a triangular antenna portion arrangement can be disposed on the surfaces of other structures—such as a substantially planar structure (for example on one or both sides of such a substantially planar structure) or a pyramid or other polyhedron (for example, on one, all, or more than one but less than all of the surfaces of such structures). Also, the triangular antenna portions can be arranged to form shapes other than squares (for example, by using more than  4  triangular antenna portions to form hexagons, larger triangles, octagons, etc.). 
     Also, if multiple instantiations of the module structure shown in  FIG. 5  are stacked in the X and Y directions to build an array, some modules can be used for cellular RF signals, others for PCS RF signals, others for AWS RF signals. In this way, a “mix and match” multi-service antenna array can be constructed in a flexible and efficient manner. Such a stacked structure can be used to create an omnidirectional array using multiple sides of the structure to transmit and receive. Such a stacked structure can be used as a steerable array by using only a single side of the overall stacked structure to transmit and receive. 
       FIG. 6  illustrates one example of a circular patch antenna  600  (suitable for use, for example, as an 800 Mhz antenna). The circular patch  600  is fed in the center (though in other embodiments it is fed in other ways). Slots  602  are used to help tune it. In some implementations, the circular patch is printed on foamboard in order to be cheap. It can be used for small cells. 
       FIG. 8  illustrates an embodiment in which the antenna element  800  comprises first and second substantially co-planar portions  802  and  804  (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions  802  and  804 , respectively) and each of the first and second substantially co-planar portions  802  and  804  have a first end and a second end  806  and  808 , wherein the first and second substantially co-planar portions  802  and  804  are arranged end-to-end with their respective first ends  806  proximate one another. The integrated RF circuitry  810  (that is, the transmitter  108  and the receiver  110 ) is disposed substantially away from the respective first ends  806  of the first and second substantially co-planar portions  802  and  804  of the antenna element  800  but operatively thereto using feed lines  812 . 
       FIG. 9  illustrates an embodiment in which the antenna element  900  comprises first and second portions  902  and  904  (for example, the transmit and receive portions  114  and  126  can be the first and second portions, respectively, or the second and first portions  902  and  904 , respectively) that are implemented as substantially non-planar structures. As shown in  FIG. 9 , each of the first and second portions  902  and  904  is implemented as a respective L-shaped structure, where each of the first and second portions  902  and  904  includes two respective planar portions. The integrated RF circuitry  906  (that is, the transmitter  108  and the receiver  110 ) is operatively coupled to the first and second portions  902  and  904 . 
       FIG. 10  illustrates an embodiment in which there are a plurality of antenna elements  1000  where each antenna element  1000  includes respective first and second portions  1002  and  1004  (for example, the transmit and receive portions  114  and  126  can be the first and second portions  1002  and  1004 , respectively, or the second and first portions  1004  and  1002 , respectively) that are implemented as substantially non-planar structures. Each of pair of first and second portions  1002  and  1004  are arranged as shown in  FIG. 10  where their respective first ends  1006  are aligned (as opposed to being arranged end-to-end). In this embodiment, each of the multiple antenna elements  1000  can be fed by the same integrated RF circuitry  1008  (that is, transmitter and receiver) (as shown in  FIG. 10 ) or by a different transmitter and receiver. 
       FIG. 11  illustrates an embodiment in which the first and second portions  1102  and  1104  of the antenna element  1100  are implemented as a respective meandering line. In this embodiment, the first and second portions  1102  and  1104  can be fed by the same integrated RF circuitry  1106  (that is, transmitter and receiver) (as shown in  FIG. 11 ) or by a different transmitter and receiver. 
       FIG. 12  illustrates an embodiment where there are multiple antenna elements  1200  (each of which having respective transmit and receive portions  1202  and  1204 ) where the integrated RF circuitry  1206  is located on one side of the antenna element arrangement as shown in  FIG. 12 . In this embodiment, each of the multiple antenna elements  1200  can be fed by the same integrated RF circuitry  1206  (that is, transmitter and receiver) (as shown in  FIG. 12 ) or by a different transmitter and receiver. 
       FIG. 13  illustrates an embodiment where the antenna element  1300  is configured as a center-fed dipole. In this embodiment, the transmit and receive portions  1302  and  1304  are center-fed by the integrated RF circuitry  1306 . 
       FIG. 14  is a block diagram of an exemplary embodiment of a distributed antenna system  1400  in which the integrated antenna modules  1405  of the type described above can be used. In the exemplary embodiment shown in  FIG. 14 , the DAS  1400  includes a host unit  1402  and one or more remote antenna units  1404 , each of which includes one or more integrated antenna modules  1405  of the type described above. In this example, the DAS  1400  includes one host unit  1402  and three remote antenna units  1404 , though it is to be understood that other numbers of host units  1402  and/or remote antenna units  1404  can be used. Moreover, it is to be understood that the integrated antenna modules described here can be used in other DAS, repeater, or distributed base station products and systems. 
     In the exemplary embodiment shown in  FIG. 14 , the host unit  1402  is communicatively coupled to each remote antenna unit  1404  over a transport communication medium or media  1406 . The transport communication media  1406  can be implemented in various ways. For example, the transport communication media  1406  can be implemented using respective separate point-to-point communication links, for example, where respective optical fiber or copper cabling is used to directly connect the host unit  1402  to each remote antenna unit  1404 . One such example is shown in  FIG. 14 , where the host unit  1402  is directly connected to each remote antenna unit  1404  using a respective optical fiber  1408 . Also, in the embodiment shown in  FIG. 14 , a single optical fiber  1408  is used to connect the host unit  1402  to each remote antenna unit  1404 , where wave division multiplexing (WDM) is used to communicate both downstream and upstream signals over the single optical fiber  1408 . In other embodiments, the host unit  1402  is directly connected to each remote antenna unit  1404  using more than one optical fiber (for example, using two optical fibers, where one optical fiber is used for communicating downstream signals and the other optical fiber is used for communicating upstream signals). Also, in other embodiments, the host unit  1402  is directly connected to one or more of the remote antenna units  1404  using other types of communication media such a coaxial cabling (for example, RG6, RG11, or RG59 coaxial cabling), twisted-pair cabling (for example, CAT-5 or CAT-6 cabling), or wireless communications (for example, microwave or free-space optical communications). 
     The transport communication media  1406  can also be implemented using shared point-to-multipoint communication media in addition to or instead of using point-to-point communication media. One example of such an implementation is where the host unit  1402  is directly coupled to an intermediary unit (also sometimes referred to as an “expansion” unit), which in turn is directly coupled to multiple remote antenna units  1404 . Another example of a shared transport implementation is where the host unit  1402  is coupled to the remote antenna units  1404  using an Internet Protocol (IP) network. 
     The host unit  1402  includes one or more transport interfaces  1410  for communicating with the remote antenna units  1404  over the transport communication medium or media  1406 . Also, each remote antenna unit  1404  includes at least one transport interface  1412  for communicating with the host unit  1402  over the transport communication medium or media  1406 . Each of the transport interfaces  1410  and  1412  include appropriate components (such as transceivers, framers, etc.) for sending and receiving data over the particular type of transport communication media used. 
     In this example, the DAS  1400  is used to distribute bi-directional wireless communications between one or more digital baseband modules  1414  and one or more wireless devices  1415  (for example, mobile telephones, mobile computers, and/or combinations thereof such as personal digital assistants (PDAs) and smartphones). 
     The techniques described here are especially useful in connection with the distribution of wireless communications that use licensed radio frequency spectrum, such as cellular radio frequency communications. Examples of such cellular RF communications include cellular communications that support one or more of the second generation (2G), third generation (3G), and fourth generation (4G) Global System for Mobile communication (GSM) family of telephony and data specifications and standards, one or more of the second generation (2G), third generation (3G), and fourth generation (4G) Code Division Multiple Access (CDMA) family of telephony and data specifications and standards, and/or the WIMAX family of specification and standards. In other embodiments, the DAS  1400 , and the improved remote antenna unit technology described here, are used with wireless communications that make use of unlicensed radio frequency spectrum such as wireless local area networking communications that support one or more of the IEEE 802.11 family of standards. In other embodiments, combinations of licensed and unlicensed radio frequency spectrum are distributed. 
     In the exemplary embodiment shown in  FIG. 14 , the host unit  1402  is communicatively coupled to one or more digital baseband modules  1414 . The host unit  1402  is configured to communicate with the digital baseband modules  1414  using a digital baseband interface  1416  of the type described above. Although the digital baseband modules  1414  are shown in  FIG. 14  as being separate from the host unit  1402 , it is to be understood that the digital baseband modules  1414  can be integrated into the host unit  1402 . 
     In the transmit or downstream direction (that is, from the host unit  1402  to the remote antenna units  1404 ), the host unit  1402  receives in-phase and quadrature digital transmit baseband data from the digital baseband modules  1414  over the digital baseband interface  1416 . The host unit  1402  then distributes at least some of the received in-phase and quadrature digital transmit baseband data to one or more of the remote antenna units  1404  over the transport communication media  1406 . For example, the host unit  1402  can be configured to distribute the same digital transmit baseband data to all of the remote antenna units  1404  and/or can be configured to distribute different digital transmit baseband data to the various remote antenna units  1404 . 
     Each remote antenna unit  1404  uses its transport interface  1412  to receive the in-phase and quadrature digital transmit baseband data communicated to it. As described above, the transmitter (not shown in  FIG. 14 ) included in each integrated antenna module  1405  is used to produce one or more analog RF transmit signals from the in-phase and quadrature digital transmit baseband data communicated to it and to radiate the produced analog RF transmit signals from the transmit portion (not shown in  FIG. 14 ) of the antenna element or elements included in that module  1405 . 
     In the receive or upstream direction (that is, from the remote antenna units  1404  to the host unit  1402 ), each remote antenna unit  1404  receives one or more analog RF receives signals via the receive portion (not shown in  FIG. 14 ) of the antenna element or elements in each integrated antenna module  1405 . The receiver (not shown in  FIG. 14 ) in each integrated antenna module  1405  receives the analog RF receive signals and produces in-phase and quadrature digital receive baseband data from the analog RF receive signals as described above. The transport interface  1412  in each remote antenna unit  1404  is used to communicate the in-phase and quadrature digital receive baseband data to the host unit  1402  over the transport communication medium  1406 . 
     For each remote antenna unit  1404 , the host unit  1402  uses an appropriate transport interface  1414  to receive the digital receive baseband data communicated to it. For each digital baseband module  1414 , the host unit  1402  provides the in-phase and quadrature digital receive baseband data received from one or more of the remote antenna units  1404  to that digital baseband module  1414  over the digital baseband interface  1416 . 
     EXAMPLE EMBODIMENTS 
     Example 1 includes an antenna module comprising integrated RF circuitry comprising at least one of a transmitter and a receiver; and an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions; wherein the integrated RF circuitry is disposed on an interior part of at least one of the first and second substantially co-planar portions. 
     Example 2 includes the antenna module of Example 1, wherein each of the first and second substantially co-planar portions have a first end and a second end, wherein the first and second substantially co-planar portions are arranged end-to-end. 
     Example 3 includes the antenna module of Example 2, wherein the first and second substantially co-planar portions are arranged end-to-end with their respective first ends proximate one another. 
     Example 4 includes any of the antenna modules of Examples 1-3, wherein the integrated RF circuitry is disposed on an interior part of both of the first and second substantially co-planar portions. 
     Example 5 includes any of the antenna modules of Examples 1-4, wherein the integrated RF circuitry is completely disposed on an interior part of only the first substantially co-planar portion. 
     Example 6 includes the antenna module of Example 5, further comprising a transmission line to operatively couple the integrated RF circuitry to the second substantially co-planar portion. 
     Example 7 includes any of the antenna modules of Examples 1-6, wherein the antenna module is deployed in a distributed antenna system. 
     Example 8 includes an antenna module comprising: integrated RF circuitry comprising at least one of a transmitter and a receiver; and an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions; wherein each of the first and second substantially co-planar portions has a first end and a second end; and wherein the integrated RF circuitry is disposed substantially adjacent to a region of the first substantially co-planar portion of the antenna element that does not include the respective first end of the first substantially co-planar portion of the antenna element. 
     Example 9 includes the antenna module of Example 8, wherein the first and second substantially co-planar portions are arranged end-to-end. 
     Example 10 includes the antenna module of Example 9, wherein the first and second substantially co-planar portions are arranged end-to-end with their respective first ends proximate one another. 
     Example 11 includes any of the antenna modules of Examples 8-10, wherein the integrated RF circuitry is disposed substantially adjacent to a respective region of the second substantially co-planar portion of the antenna element that does not include the respective first end of the second substantially co-planar portion of the antenna element. 
     Example 12 includes any of the antenna modules of Examples 8-11, wherein the integrated RF circuitry is disposed substantially adjacent to the respective second end of the first substantially co-planar portion of the antenna element. 
     Example 13 includes any of the antenna modules of Examples 8-12, further comprising a transmission line to operatively couple the integrated RF circuitry to the first substantially co-planar portion. 
     Example 14 includes the antenna module of Example 13, wherein the transmission line operatively couples the integrated RF circuitry to the respective first end of the first substantially co-planar portion. 
     Example 15 includes any of the antenna modules of Examples 8-14, wherein the antenna module is deployed in a distributed antenna system. 
     Example 16 includes an antenna module comprising: a radio frequency transmitter; a radio frequency receiver; and an antenna element operatively coupled to the radio frequency transmitter and radio frequency receiver; wherein the antenna element comprising first and second substantially co-planar portions; wherein the radio frequency transmitter is operatively coupled to the first substantially co-planar portion of the antenna element; wherein the radio frequency receiver is operatively coupled to the second substantially co-planar portion of the antenna element; wherein each of the first and second substantially co-planar portions has a first end and a second end; and wherein the first and second substantially co-planar portions are arranged end-to-end with their respective first ends substantially separated from one another within the antenna module. 
     Examples 17 includes the antenna module of Example 16, wherein the radio frequency transmitter is disposed substantially adjacent the respective first end of the first substantially co-planar portion of the antenna element. 
     Example 18 includes any of the antenna modules of Examples 16-17, wherein the radio frequency transmitter is directly coupled to the first substantially co-planar portion of the antenna element. 
     Example 19 includes the antenna module of Example 18, wherein the radio frequency transmitter is directly coupled to the first substantially co-planar portion of the antenna element without the use of a separate cable or wire. 
     Example 20 includes any of the antenna modules of Examples 16-19, wherein the radio frequency receiver is disposed substantially adjacent the respective first end of the second substantially co-planar portion of the antenna element. 
     Example 21 includes any of the antenna modules of Examples 16-20, wherein the radio frequency receiver is directly coupled to the second substantially co-planar portion of the antenna element. 
     Example 22 includes any of the antenna modules of Examples 16-21, wherein the radio frequency receiver is directly coupled to the second substantially co-planar portion of the antenna element without the use of a separate cable or wire. 
     Example 23 includes any of the antenna modules of Examples 16-22, wherein the antenna module is deployed in a distributed antenna system. 
     Example 24 includes an antenna module comprising: integrated RF circuitry comprising at least one of a transmitter and a receiver; and an antenna element operatively coupled to the integrated RF circuitry, the antenna element comprising first and second substantially co-planar portions; wherein each of the first and second substantially co-planar portions has a first end and a second end; wherein the first and second substantially co-planar portions are arranged with their respective first ends proximate one another and offset from one another; and wherein the integrated RF circuitry is disposed substantially adjacent the respective first ends of the first and second substantially co-planar portions of the antenna element. 
     Example 25 includes the antenna module of Example 24, wherein the antenna module is deployed in a distributed antenna system. 
     Example 26 includes a radio frequency (RF) module for use in a communication device of a communication system, the module comprising integrated RF circuitry comprising at least one of a transmitter and a receiver; and an antenna element operatively coupled to the integrated RF circuitry; wherein the antenna element comprises first and second planar portions, wherein the first planar portion is disposed in a first plane and the second planar portion is disposed in a second plane; wherein each of the first and second planar portions has a respective first end and a respective second end; wherein the first and second planar portions are arranged within the respective first and second planes end-to-end with their respective first ends proximate one another; wherein the integrated RF circuitry is disposed substantially adjacent the respective first ends of the first and second planar portions of the antenna element. 
     Example 27 includes the antenna module of Example 26, wherein the antenna module is deployed in a distributed antenna system. 
     Example 28 includes any of the antenna modules of Examples 26-27, further comprising a substrate having a ground plane, wherein the substrate has first and second opposing surfaces separated by the ground plane, wherein the first plane in which the first planar portion of the antenna element is disposed comprises the first surface of the substrate, and wherein the second plane in which the second planar portion of the antenna element is disposed comprises the second surface of the substrate. 
     Example 29 includes any of the antenna modules of Examples 26-28, wherein the integrated RF circuitry comprises first and second surfaces, wherein the first plane in which the first planar portion of the antenna element is disposed comprises the first surface of the RF circuitry, and wherein the second plane in which the second planar portion of the antenna element is disposed comprises the second surface of the integrated RF circuitry. 
     Also, other examples include combinations of the individual features of the above-described Examples. 
     A number of embodiments have been described. Nevertheless, it will be understood that various modifications to the described embodiments may be made without departing from the spirit and scope of the claimed invention. Also, combinations of the individual features of the above-described embodiments are considered within the scope of the inventions disclosed here.