Antenna array with integrated filters
An exemplary antenna system has first and second antenna elements, where a diplexer is connected to each second element. First phase shifters are connected to the first elements and to the diplexers, and second phase shifters are connected to the diplexers, but not to the first elements. Either a different bandpass filter is connected to the first and second phase shifters or a single multiplexer is connected to all phase shifters. The antenna system can be used to support communications over first and second sub-bands with independent beam tilts and equivalent beamwidths, where all of the elements are used for the first sub-band, and the second elements, but not the first elements, are used for the second sub-band. Each first element is separated from an adjacent element by a first distance, and each second element is separated from an adjacent element by a second distance different from the first distance.
1. A system comprising:
a plurality of first antenna elements configured to operate in a first frequency sub-band;
a plurality of second antenna elements configured to operate in the first frequency sub-band and a second frequency sub-band, wherein the second antenna elements are arranged in a linear array, and wherein the first antenna elements are distributed on first and second ends of the linear array opposite from each other;
a plurality of multiplexing filters, each connected between a respective one of the plurality of second antenna elements and a first phase shifter network, wherein the first phase shifter network is connected to each first antenna element and to each multiplexing filter;
a second phase shifter network connected to each multiplexing filter and isolated from the first antenna elements; and
one or more frequency filters connected to the first and second phase shifter networks.
2. The system of claim 1 , wherein beam tilt for the first frequency sub-band is independent of beam tilt for the second frequency sub-band.
3. The system of claim 1 , wherein a first azimuth beamwidth for the first frequency sub-band is substantially equal to a second azimuth beamwidth for the second frequency sub-band.
4. The system of claim 1 , wherein each first antenna element has a bandwidth different from a bandwidth of each second antenna element.
5. The system of claim 1 , wherein:
each first antenna element is separated from an adjacent antenna element by a first distance; and
each second antenna element is separated from an adjacent antenna element by a second distance different from the first distance.
6. The system of claim 1 , wherein the first phase shifter network is connected directly to each first antenna element without any intervening multiplexing filter.
7. The system of claim 1 , wherein each multiplexing filter is a diplexing filter.
8. The system of claim 1 , further comprising:
a plurality of third antenna elements configured to communicate simultaneously via the first frequency sub-band, the second frequency sub-band, and a third frequency sub-band;
a second plurality of multiplexing filters respectively connected to each third antenna element; and
a third phase shifter network connected to each multiplexing filter in the second plurality of multiplexing filters and isolated from each first antenna element and from each second antenna element, wherein:
the first phase shifter network is connected to each third antenna element;
the second phase shifter network is connected to each third antenna element; and
the one or more frequency filters are further connected to the third phase shifter network.
9. The system of claim 8 , wherein:
each multiplexing filter in the plurality of multiplexing filters comprises a diplexing filter; and
each multiplexing filter in the second plurality of multiplexing filters comprises a triplexing filter.
10. The system of claim 1 , wherein the one or more frequency filters comprise:
a first bandpass filter connected to the first phase shifter network; and
a second bandpass filter connected to the second phase shifter network.
11. The system of claim 1 , wherein the one or more frequency filters comprise a single multiplexing filter connected to both the first phase shifter network and the second phase shifter network.
12. A system comprising:
a linear array of antenna elements comprising a first plurality of antenna elements and a second plurality of antenna elements, wherein the first plurality of antenna elements are configured to support communications via a first frequency sub-band, and wherein the second plurality of antenna elements are configured to support communications via the first frequency sub-band and a second frequency sub-band;
a first phase shifter network coupled to each and every antenna element of the system configured to support communications via the first frequency sub-band;
a second phase shifter network coupled to only the second plurality of antenna elements and isolated from the first plurality of antenna elements; and
a plurality of multiplexers respectively coupled to each antenna element of the second plurality of antenna elements, the first phase shifter network, and the second phase shifter network,
wherein the first phase shifter network adjusts a beam tilt for the first frequency sub-band, and is independent from the second phase shifter network, which adjusts a beam tilt for the second frequency sub-band.
13. The system of claim 12 , wherein the second phase shifter network is connected to each multiplexer of the plurality of multiplexers and is isolated from the second plurality of antenna elements.
14. An apparatus comprising:
a first plurality of antenna elements, wherein each antenna element of the first plurality of antenna elements supports a first bandwidth that includes a first frequency sub-band;
a second plurality of antenna elements, wherein each antenna element of the second plurality of antenna elements supports a second bandwidth greater than the first bandwidth and that includes the first frequency sub-band and a second frequency sub-band that does not overlap the first frequency sub-band;
a first phase shifter network;
a second phase shifter network; and
a plurality of multiplexers, wherein each multiplexer of the plurality of multiplexers is connected between a respective antenna element of the second plurality of antenna elements the first phase shifter network, and the second phase shifter network,
wherein the first phase shifter network is connected to the multiplexers and to each antenna element of the first plurality of antenna elements,
wherein the second phase shifter network is connected to the multiplexers and isolated from the first plurality of antenna elements.
15. The apparatus of claim 14 , further comprising:
one or more frequency filters connected to the first and second phase shifter networks.
16. The apparatus of claim 14 , wherein each multiplexer comprises a non-cavity diplexing filter.
17. The apparatus of claim 14 , wherein each antenna element of the first plurality of antenna elements is more directive than each antenna element of the second plurality of antenna elements.
18. The apparatus of claim 14 , wherein the first plurality of antenna elements and the second plurality of antenna elements are configured to form a first beam having a first frequency in the first frequency sub-band and having a first azimuth beamwidth, and wherein the second plurality of antenna elements are configured to form a second beam having a second frequency in the second frequency sub-band and having a second azimuth beamwidth that is greater than the first azimuth beamwidth.