Base station antenna with high performance active antenna system (AAS) integrated therein
A base station antenna includes a first antenna having first and second spaced-apart columns of first radiating elements therein, which are configured to operate within a first frequency band. An active antenna system (AAS) is provided, which is configured to operate within a second, typically higher, frequency band. The AAS includes a second antenna within a space between the first and second columns of first radiating elements. These first radiating elements may include tilted feed stalks which support higher integration by enabling the first radiating elements to overhang at least a portion of the second antenna.
1. A radio unit for a base station antenna, comprising:
a filter unit having a plurality of filters and a plurality of calibration couplers therein, said plurality of calibration couplers having respective inputs electrically coupled to corresponding outputs of the plurality of filters; and
a radio having a plurality of outputs electrically coupled to a corresponding plurality of input terminals of said plurality of filters, said radio comprising a calibration circuit, which is: (i) responsive to calibration feedback signals that are generated at a plurality of outputs of said plurality of calibration couplers and bypass the plurality of filters, and are provided as feedback directly to the calibration circuit during transmitter (Tx) calibration, and (ii) configured to inject respective radio frequency (RF) calibration signals through the plurality of calibration couplers during receiver (Rx) calibration; and
wherein the RF calibration signals bypass the plurality of filters during said Rx calibration.
2. The radio unit of claim 1 , wherein said filter unit comprises a housing having said plurality of calibration couplers therein; wherein at least some of the plurality of outputs of said plurality of calibration couplers are electrically coupled together within the housing; and wherein said calibration circuit comprises a strip line that receives the calibration feedback signals.
3. The radio unit of claim 2 , wherein said calibration circuit is electrically coupled to an output of the housing, which provides a combination of at least some of the calibration feedback signals to the strip line.
4. The radio unit of claim 1 , wherein said calibration circuit is electrically coupled to an output of the housing, which provides a combination of at least some of the calibration feedback signals.
5. The radio unit of claim 1 , wherein the housing has four or more calibration couplers therein having respective outputs that are electrically connected together within the housing.
6. The radio unit of claim 1 , further comprising a reflector having an array of radiating elements on a front facing surface thereof.
7. The radio unit of claim 6 , further comprising:
a plurality of feed boards on the front facing surface of said reflector; and
a plurality of phase shifters on the plurality of feed boards.
8. The radio unit of claim 7 , wherein said filter unit comprises a housing having the plurality of calibration couplers therein; and wherein at least some of the plurality of outputs of the plurality of calibration couplers are electrically coupled together within the housing.
9. A radio unit for a base station antenna, comprising:
a filter unit having a plurality of filters and a plurality of calibration couplers therein, said plurality of calibration couplers having respective inputs electrically coupled to corresponding outputs of the plurality of filters;
a radio having a plurality of outputs electrically coupled to a corresponding plurality of input terminals of said plurality of filters, said radio comprising a calibration circuit responsive to calibration feedback signals generated at a plurality of outputs of said plurality of calibration couplers;
a reflector having a plurality of columns of radiating elements on a front-facing surface thereof; and
an at least single channel phase shifter extending at least a majority of the length of the plurality of columns of radiating elements, on a rear-facing surface of said reflector.
10. The radio unit of claim 9 , wherein the at least single channel phase shifter comprises a plurality of dual channel phase shifters, which are aligned to the plurality of columns of radiating elements.
11. The radio unit of claim 10 , wherein at least some of the plurality of filters extend between the plurality of dual channel phase shifters.
12. The radio unit of claim 11 , wherein each of the plurality of filters is mounted to a first side of a corresponding one of the plurality of dual channel phase shifters.
13. The radio unit of claim 10 , wherein said reflector comprises first and second chokes extending along first and second opposing rear sides of said reflector, respectively.
14. The radio unit of claim 13 , wherein the plurality of dual channel phase shifters extend between the first and second chokes.
15. The radio unit of claim 13 , wherein the plurality of dual channel phase shifters and the plurality of filters extend between the first and second chokes.
16. The radio unit of claim 9 , wherein the calibration feedback signals are generated at the plurality of outputs of said plurality of calibration couplers and bypass the plurality of filters, and are provided as feedback directly to the calibration circuit during transmitter (Tx) calibration; wherein the calibration circuit is further configured to inject respective radio frequency (RF) calibration signals through the plurality of calibration couplers during receiver (Rx) calibration; and wherein the RF calibration signals bypass the plurality of filters during said Rx calibration.