Multiband active-passive base station antenna

Generally described, the present disclosure relates to antennas with an active component and a passive component, generally referred to as an active-passive antenna. More specifically, aspects of the present application include a combination of an active antenna element configured to process communications in accordance with a first frequency bandwidth and a passive antenna element configured to process communication in accordance with a second frequency bandwidth. Still further, the present disclosure includes the integration of the active and passive antenna components as well as the utilization of components of traditional active array antennas to allow the incorporation of the active-passive antenna in the same form factor previously utilized for solely active array antennas.

BACKGROUND

Base station antenna deployment has generally been done with passive antennas, such as fixed electrical tilt (FET), mechanical electrical tilt (MET), and remote electrical tilt (RET) antennas. Over the years, the increased use of spectrum has resulted in increased complexity starting from mostly single band FET antennas gradually moving to multiband RET antennas. However, these antennas are passive antennas, and do not contain any active RF devices such as amplifiers and radios within the antenna. Therefore, these antennas still have significant RF losses from the radiating element to the first active device. For example, the first active device can be a NodeB, a Tower Mounted Amplifier (TMA), or a Remote Radio Head (RRH). The magnitude of these RF losses can be in the order of several dB, which can significantly affect system performance.

In active antenna environments, RF losses disappear because active devices, such as low noise amplifiers (LNAs) in the uplink path or power amplifiers (PAs) in the downlink path, are brought into as close as possible to the antenna radiating element. The proximity of the antenna radiating element to the active devices mitigates many of the losses associated with passive antenna radiating elements, such as feed network losses, phase shifter losses, and cable feeder losses. The beam can be then formed with an electronic phase shifter, in the analog or digital domain.

In an active antenna, an array of broadband radiating elements can be combined with distributed modules. Each distributed module may contain a double triplexer, double LNA, double PA, phase shifters and attenuators, and may also be combined with a passive feed network, with a passive phase shifter. These modules are compact and essential building blocks of the all antennas. While operators are very pleased with the improved performance that can be brought by active antennas, the challenge remains when multiple technologies, such as second generation air interface standards (“2G”), third generation air interface standards (“3G”), and fourth generation air interface standards (“4G”) are combined on the same tower, or on the same antenna due to tower loading and zoning restrictions.

DETAILED DESCRIPTION

Generally described, the present disclosure relates to antennas with an active component and a passive component, generally referred to as an active-passive antenna. More specifically, aspects of the present application include a combination of an active antenna element configured to process communications in accordance with a first frequency bandwidth and a passive antenna element configured to process communication in accordance with a second frequency bandwidth. Still further, the present disclosure includes the integration of the active and passive antenna components as well as the utilization of components of traditional active array antennas to allow the incorporation of the active-passive antenna in the same form factor previously utilized for solely active array antennas.

FIG. 1illustrates a connection between a set of radiating elements10and a first active device20, where only passive antennas are present. The embodiment shown inFIG. 1illustrates a single polarization example, such as for example +/−45° polarization. In other embodiments, different angles of polarization, or different numbers of polarization, may be possible. With continued reference toFIG. 1, the radiating elements are connected to an antenna feed network12, forming the passive antenna. Illustratively, the antenna feed network may include a corporate feed network (now shown) and a plurality of passive phase shifters14attached to a remote electrical tilt (RET) antenna (not shown). The passive antenna feed network12may be configured to handle high power, for example about 250W per port. The signals from the antenna feed network12may then be fed into a combiner/divider14and the combined signal may then be sent out via an RF connector18to an active component20. The active component20can be for example, a NodeB, a Tower Mounted Amplifier (TMA), or a Remote Radio Head (RRH). One skilled in the art will appreciate that passive antennas which do not contain any active RF devices such as amplifiers and radios within the antenna generally have significant RF losses from the radiating element to the active component20.

FIGS. 2A-2Care block diagrams of embodiments of an active-passive antenna200. Similar to the embodiment illustrated inFIG. 1, the embodiment shown inFIGS. 2A-2Cillustrate a single polarization example, such as for example +/−45° polarization. In other embodiments, different angles of polarization, or multiple numbers of polarization may be possible. The active-passive antenna illustrated inFIGS. 2A-2Cmay, in some embodiments, cover an Advanced Wireless Systems (AWS) Band with Long-Term Evolution (LTE) technology with an active component, and may also cover a Personal Communications Service (PCS) Band with a passive component.

With reference toFIG. 2A, there are sets of distributed double triplexers220, behind each pair of radiating element210. Generally, triplexers220are used to separate the different bands of frequencies on the up and down links in both active and passive components. In some embodiments, the triplexers200may separate signals in downlink(s) (DL) and uplink(s) (UL) in a passive band and in an active band. Double triplexers220cover two-slant polarization (such as for example +/−45°, and the like). In other embodiments, different types of triplexers, or other multiplexers may be used to cover different levels and/or angles of polarization may be implemented. Additionally, while four pairs of radiating elements210and triplexers220are illustrated inFIG. 2A, one skilled in the relevant that different number of radiating elements may be incorporated into an active-passive antenna200.

With continued reference toFIG. 2A, the double triplexers220may define three branches220a,220band220cof the active-passive antenna200. Branch220aof each of the triplexers may connect to a first active antenna component230, which will be described with regard toFIG. 2B. Branch220bof each of the triplexers may connect to a passive antenna component250, which will be described with regard toFIG. 2C. Additionally, branch220cof each of the triplexers may connect to a second active antenna component260, which will be described with regard toFIG. 2D. One skilled in the relevant art will appreciate that in the event that only a single active component is included in the active-passive antenna200, branch220cand the second active antenna component260can be omitted.

Referring now toFIG. 2B, the first active component230can include a distributed LNA232for each triplexer220in the active-passive antenna200. A distributed LNA232helps to minimize the system noise figure. In some embodiments, the LNA232may include an amplifier and an analog predistortion (APD) module. After the LNA232, an electronic phase shifter234may be used to add flexibility to the vertical beam forming of the signal on branch220a. The electrical phase shifter234may have a wide range of vertical downtilt, and variable upper side lobe suppression (USLS) to maximize antenna gain and/or minimize interference from adjacent cell site. From the electrical phase shifter234, the signal may be input to an electronic attenuator236. The signals from the branches220aof the plurality of triplexers220may then be fed into a combiner/divider238and the combined signal may then be fed into a preamplifier240before being fed into a radio transmitter242. The radio transmitter242may have a standard base station interface244, such as for example a common public radio interface (CPRI), in order to transmit to other base stations. The passive-active antenna200may in some embodiments cover an active uplink channel (“UL”) in the 1710-1755 MHz band, such as the band used in LTE technology via the signals on the branch220aof the triplexers220.

With reference now toFIG. 2C, the passive antenna component250can include a passive antenna feed network252. In some embodiments, the antenna feed network252may include a corporate feed network (now shown) and a plurality of passive phase shifters254attached to a remote electrical tilt (RET) antenna (not shown). The passive antenna feed network252may be configured to handle high power, for example about 250W per port. The signals from the antenna feed network252may then be fed into a combiner/divider256and the combined signal may then be sent out via an RF connector258. The passive-active antenna200may in some embodiments cover a passive uplink channel in the 1850-1995 MHz band, such as the band used in personal communication services (“PCS”) technology via the signals on branch220bof the triplexers220.

Turning now toFIG. 2D, as previously discussed, in some embodiments, a second active antenna component260may also be active in some embodiments. The second active antenna component260may be connected, via a standard interface272, to the input of a radio receiver270. The signal received by the radio receiver270may be split by the divider/combiner268to be distributed to electronic attenuators266and electronic phase shifters264, and distributed power attenuators (PA)262. The signals from each of the PAs262may then be fed into each of the220cbranch of the triplexers220. The active-passive antenna200may in some embodiments cover an active downlink channel (“DL”) in the 2110-2155 MHz band, such as the band used in LTE Technology via the signals on branch220cof the triplexers200.

Below is a list of examples of different combinations of passive frequencies and active UL and DL frequencies where using a single broad band element can be combined with multiplexers to obtain an integrated active-passive base station antenna array, for various bandwidths of radiating elements, using the embodiments described herein. Other variations of spectrum block usage may also be available, depending on countries/region/operators. Accordingly, the examples indicating in the present disclosure and the below table should not be construed as limiting.

FIG. 3is a perspective view an embodiment of the active-passive antenna200.FIG. 4correspond to a side view of an active array antenna200. As illustrated inFIGS. 3 and 4, the use of an active-passive antenna200allows for a reduced physical footprint of an active-passive antenna200. More specifically, in one aspect, the dimensions of an active-passive antenna200will be substantially the same as a passive antenna component, such as the antenna component illustrated inFIG. 1. Accordingly, no modification of the dimensions of the active-passive antenna200to allow for the inclusion of one or more active modes. In some embodiments, multiplexers already present or configured for an antenna are used to enable the active-passive antenna200to operate in both active and passive bands. The reuse of components thus enables the active-passive antenna200to remain in the same form factor as before the addition of the passive band.

While illustrative embodiments have been disclosed and discussed, one skilled in the relevant art will appreciate that additional or alternative embodiments may be implemented within the spirit and scope of the present disclosure. Additionally, although many embodiments have been indicated as illustrative, one skilled in the relevant art will appreciate that the illustrative embodiments do not need to be combined or implemented together. As such, some illustrative embodiments do not need to be utilized or implemented in accordance with the scope of variations to the present disclosure.

Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements or steps. Thus, such conditional language is not generally intended to imply that features, elements or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements or steps are included or are to be performed in any particular embodiment. Moreover, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey utilization of the conjunction “or” in enumerating a list of elements does not limit the selection of only a single element and can include the combination of two or more elements.

Any process descriptions, elements, or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those skilled in the art. It will further be appreciated that the data and/or components described above may be stored on a computer-readable medium and loaded into memory of the computing device using a drive mechanism associated with a computer-readable medium storing the computer executable components, such as a CD-ROM, DVD-ROM, or network interface. Further, the component and/or data can be included in a single device or distributed in any manner. Accordingly, general purpose computing devices may be configured to implement the processes, algorithms and methodology of the present disclosure with the processing and/or execution of the various data and/or components described above. Alternatively, some or all of the methods described herein may alternatively be embodied in specialized computer hardware. In addition, the components referred to herein may be implemented in hardware, software, firmware or a combination thereof.