Enhanced phase shifter circuit to reduce RF cables
A multi-band antenna system includes an array of wide-band radiating elements and a multi-band electrical tilt circuit. The multi-band electrical tilt circuit includes a plurality of combiners, a first RF band variable phase shifter and a second RF band variable phase shifter implemented in a common medium. The common medium may comprise a PCB, a stripline circuit, or the like. Each combiner includes a combined port, a first RF band port, and a second RF band port. The combined ports are coupled to the radiating elements. The first RF band phase shifter has a first plurality of variably phase shifted ports connected to the first RF band ports of the combiners via transmission line, and the second RF band phase shifter has a second plurality of variably phase-shifted ports connected to the second RF band ports of the combiners via transmission line. The phase shifters are independently configurable.
1. A multi-band antenna system, comprising:
an array of wide-band radiating elements;
a multi-band electrical tilt circuit implemented in a common medium, comprising:
a plurality of combiners, each combiner having a combined port, a first RF band port, and a second RF band port, the combined ports of the combiners being coupled to the array of wide-band radiating elements;
a first RF band variable phase shifter having a first plurality of variably phase shifted ports connected to the first RF band ports of the plurality of combiners via a first plurality of transmission lines; and
a second RF band variable phase shifter having a second plurality of variably phase-shifted ports connected to the second RF band ports of the plurality of combiners via a second plurality of transmission lines;
wherein said first RF band variable phase shifter is configurable independently from said second RF band variable phase shifter.
2. The multi-band antenna system of claim 1 , wherein the common medium comprises a single printed circuit board, and the plurality of combiners, at least a fixed portion of the first RF band variable phase shifter and at least a fixed portion of the second RF band variable phase shifter are fabricated as part of the single printed circuit board.
3. The multi-band antenna system of claim 1 , further comprising a third RF band phase shifter having a third plurality of variably phase-shifted ports, and wherein each combiner further comprises a third RF band port coupled to the third plurality of variably phase-shifted ports.
4. The multi-band antenna system of claim 1 , further comprising a plurality of arrays of wide-band radiating elements.
5. The multi-band antenna system of claim 1 , wherein a number of combiners equals a number of wide-band radiating elements.
6. The multi-band antenna system of claim 1 , wherein the wide-band radiating elements comprise dual-polarized wide-band radiating elements and the multi-band electrical tilt circuit comprises a first polarization multi-band electrical tilt circuit, coupled to a first polarization element of the dual-polarized wide-band radiating elements, the multi-band antenna system further comprising a second polarization multi-band electrical tilt circuit coupled to a second polarization element of the dual-polarized wide-band radiating elements.
7. The multi-band antenna system of claim 1 , wherein the combiners are implemented using stepped impedance microstrip on PCB.
8. The multi-band antenna system of claim 1 , wherein each combiner further comprises a diplexer.
9. The multi-band antenna system of claim 1 , wherein each combiner further comprises a duplexer.
10. The multi-band antenna system of claim 1 , wherein the common medium comprises a stripline assembly, and the plurality of combiners, a fixed portion of the first RF band variable phase shifter and a fixed portion of the second RF band variable phase shifter are all fabricated as part of the stripline assembly.
11. The multi-band antenna system of claim 1 , wherein each combiner further comprises a notch filter.
12. The multi-band antenna system of claim 1 , wherein each combiner comprises a stop-band filter.
13. The multi-band antenna system of claim 12 , wherein each stop-band filter comprises at least one resonant stub.
14. A multi-band antenna system, comprising:
an array of dual polarized wide-band radiating elements, the dual polarized wide-band radiating elements including a first polarization feed and a second polarization feed;
a first polarization multi-band electrical tilt circuit implemented in a first common medium, comprising:
a plurality of first polarization combiners, each combiner having a combined port, a first RF band port, and a second RF band port, the combined ports of the combiners being coupled to the first polarization feed of the array of dual polarized wide-band radiating elements;
a first RF band first polarization variable phase shifter having a first plurality of variably phase-shifted ports connected to the respective first RF band ports of the plurality of first polarization combiners via a first plurality of transmission lines; and
a second RF band phase first polarization variable shifter having a second plurality of variably phase-shifted ports connected to the respective second RF band ports of the plurality of first polarization combiners via a second plurality of transmission lines; and
a second polarization multi-band electrical tilt circuit implemented in a second common medium, comprising:
a plurality of second polarization combiners, each combiner having a combined port, a first RF band port, and a second RF band port, the combined ports of the second polarization combiners being coupled to the second polarization feed of the array of wide-band radiating elements;
a first RF band second polarization variable phase shifter having a first plurality of variably phase shifted ports connected to the respective first RF band ports of the plurality of second polarization combiners via a third plurality of transmission lines; and
a second RF band second polarization variable phase shifter having a second plurality of variably phase shifted ports connected to the respective second RF band ports of the plurality of second polarization combiners via a fourth plurality of transmission lines;
wherein the first RF band variable phase shifters of the first polarization multi-band electrical tilt circuit is configurable independently from the second RF band variable phase shifters of the first polarization multi-band electrical tilt circuit and the first RF band variable phase shifter of the second polarization multi-band electrical tilt circuit is configurable independently from the second RF band variable phase shifter of the second polarization multi-band electrical tilt circuit.
15. The multi-band antenna system of claim 14 , wherein the first common medium and second common medium each comprise a single printed circuit board, and the plurality of combiners, at least a fixed portion of the first RF band variable phase shifter and at least a fixed portion of the second RF band variable phase shifter of each of the first polarization multi-band electrical tilt circuit and second polarization multi-band electrical tilt circuit are fabricated as part of the single printed circuit board.
16. A method comprising:
fabricating on a printed circuit board a fixed portion of a first RF band variable phase shifter;
fabricating on the printed circuit board a fixed portion of a second RF band variable phase shifter;
fabricating on the printed circuit board a plurality of combiners, wherein each combiner comprises a combined port, a first RF band port, and a second RF band port, wherein each combiner is connected to the first RF band variable phase shifter via the first RF band port by a first microstrip transmission line and wherein each combiner is connected to the second RF band variable phase shifter via the second RF band port by a second microstrip transmission line; and
installing on the printed circuit board a non-fixed portion of the first RF band variable phase shifter and a non-fixed portion of the second RF band variable phase shifter such that the first RF band variable phase shifter and the second RF band variable phase shifter are independently configurable.
17. The method of claim 16 , wherein fabricating the plurality of combiners comprises fabricating at least one combiner as a microstrip-fed cavity filter comprising a cavity housing.
18. The method of claim 16 , wherein fabricating the plurality of combiners comprises fabricating at least one combiner as a notch filter.
19. The method of claim 16 , wherein fabricating the plurality of combiners comprises fabricating at least one stop-band filter.
20. The method of claim 19 , wherein fabricating the at least one stop-band filter comprises fabricating at least one resonant stub.