Communication systems with enhanced isolation provision and optimized impedance matching

1. A communication system comprising:

a plurality of paths comprising one or more first paths for processing first signals and one or more second paths for processing second signals;

one or more power amplifiers (PAs) coupled respectively to the one or more first paths for amplifying the first signals;

one or more low noise amplifiers (LNAs) coupled respectively to the one or more second paths for amplifying the second signals;

one or more first filter modules coupled respectively to the one or more first paths for filtering the first signals;

one or more second filter modules coupled respectively to the one or more second paths for filtering the second signals; and

a multi-feed antenna, the multi-feed antenna comprising:

a ground plane;

a radiating element positioned above the ground plane and having a first feed port associated therewith;

a second element coupled to the ground plane and positioned adjacent to the radiating element, the second element having a second feed port associated therewith;

a third element coupled to the ground plane and positioned adjacent to at least one of the radiating element and the second element, the third element having a third feed port associated therewith;

each of the first through third feed ports being coupled to one of the plurality of paths, respectively, to provide physical separation of the plurality of paths from each other, the multi-feed antenna being configured to provide impedance matching for each of the plurality of paths, wherein the multi-feed antenna transmits first signals and receives second signals,

wherein

the physical separation of the plurality of paths and the impedance matching for each of the plurality of paths provide isolation among the plurality of paths, and relax rejection considerations on the one or more first filter modules and the one or more second filter modules.

2. The communication system of claiml, wherein

the impedance matching is configured to optimize efficiency of the one or more PAs and the one or more LNAs.

3. The communication system of claim 1 , wherein

the relaxed rejection considerations on the one or more first filter modules and the one or more second filter modules reduces insertion loss.

4. The communication system of claim 1 , wherein

the isolation reduces a power leak from one path to another.

5. The communication system of claim 4 , wherein

the power leak is from at least one of the one or more first paths to at least one of the one or more second paths when the multi-feed antenna transmits the first signals; and

the rejection considerations on at least one of the one or more second filter modules coupled to the at least one of the one or more second paths are substantially relaxed.

6. The communication system of claim 1 , further comprising:

one or more first phase shifters respectively coupled to the one or more first paths; and

one or more second phase shifters respectively coupled to the one or more second paths, wherein

the one or more first phase shifters are configured to adjust phases of the first signals and the one or more second phase shifters are configured to adjust phases of the second signals to improve the impedance matching to increase the isolation.

7. The communication system of claim 6 , wherein

at least one of the one or more first phase shifters and the one or more second phase shifters is configured to be part of the multi-feed antenna.

8. The communication system of claim 1 , wherein

at least one of the plurality of paths is configured to process signals in a plurality of combinations, each combination being a pair of a mode and a band, during different time intervals; and

the multi-feed antenna is further configured to optimize frequency response for each of the plurality of combinations during the time interval.

9. The communication system of claim 8 , wherein

the signals comprise the first signals;

at least one PA respectively coupled to the at least one of the plurality of paths is configured to amplify the first signals in the plurality of combinations during the different time intervals; and

at least one first filter module respectively coupled to the at least one of the plurality of paths is configured to filter the first signals in the plurality of combinations during the different time intervals.

10. The communication system of claim 9 , further comprising:

at least one first phase shifter respectively coupled to the at least one of the plurality of paths to adjust phases of the first signals in the plurality of combinations during the different time intervals to improve the impedance matching to increase the isolation.

11. The communication system of claim 10 , wherein

the at least one first phase shifter is configured to be part of the multi-feed antenna.

12. The communication system of claim 9 , wherein

each of the at least one first filter module comprises a plurality of filters corresponding to the plurality of combinations, respectively, and is configured to select one of the plurality of filters to filter the first signals in a combination during a time interval.

13. The communication system of claim 9 , wherein

each of the at least one first filter module comprises one or more selected from a group consisting of tunable components and active elements to adjust filter characteristics depending on the combinations.

14. The communication system of claim 8 , wherein

the signals comprise the second signals;

at least one LNA respectively coupled to the at least one of the plurality of paths is configured to amplify the second signals in the plurality of combinations during the different time intervals; and

at least one second filter module respectively coupled to the at least one of the plurality of paths is configured to filter the second signals in the plurality of combinations during the different time intervals.

15. The communication system of claim 14 , further comprising:

at least one second phase shifter respectively coupled to the at least one of the plurality of paths to adjust phases of the second signals in the plurality of combinations during the different time intervals to improve the impedance matching to increase the isolation.

16. The communication system of claim 15 , wherein

the at least one second phase shifter is configured to be part of the multi-feed.

17. The communication system of claim 14 , wherein

each of the at least one second filter module comprises a plurality of filters corresponding to the plurality of combinations, respectively, and is configured to select one of the plurality of filters to filter the second signals in a combination during a time interval.

18. The communication system of claim 14 , wherein

each of the at least one second filter module comprises one or more selected from a group consisting of tunable components and active elements to adjust filter characteristics depending on the combinations.

19. The communication system of claim 1 , wherein

at least one of the plurality of paths is configured to process signals in at least one combination, respectively, the combination being a pair of a mode and a band; and

the multi-feed antenna is further configured to optimize frequency response for the at least one combination.

20. The communication system of claim 19 , wherein

the signals comprise the first signals;

at least one PA respectively coupled to the at least one of the plurality of paths is configured to amplify the first signals in the at least one combination, respectively; and

at least one first filter module respectively coupled to the at least one of the plurality of paths is configured to filter the first signals in the at least one combination, respectively, each of the at least one first filter module comprising a filter corresponding to a combination.

21. The communication system of claim 19 , further comprising:

at least one first phase shifter respectively coupled to the at least one of the plurality of paths to adjust phases of the first signals in the at least one combination, respectively, to improve the impedance matching to increase the isolation.

22. The communication system of claim 21 , wherein

the at least one first phase shifter is configured to be part of the multi-feed antenna.

23. The communication system of claim 19 , wherein

the signals comprise the second signals;

at least one LNA respectively coupled to the at least one of the plurality of paths is configured to amplify the second signals in the at least one combination, respectively; and

at least one second filter module respectively coupled to the at least one of the plurality of paths is configured to filter the second signals in the at least one combination, respectively, each of the at least one second filter module comprising a filter corresponding to a combination.

24. The communication system of claim 23 , further comprising:

at least one second phase shifter respectively coupled to the at least one of the plurality of paths to adjust phases of the second signals in the at least one combination, respectively, to improve the impedance matching to increase the isolation.

25. The communication system of claim 24 , wherein

the at least one second phase shifter is configured to be part of the multi-feed antenna.

26. A communication system, comprising:

a plurality of antennas including one or more multi-feed antennas, each of the one or more multi-feed antennas including:

a ground plane;

a radiating element positioned above the ground plane and having a first feed port associated therewith; and

at least a second element coupled to the ground plane and positioned adjacent to the radiating element, the second element having a second feed port associated therewith;

each of the feed ports being coupled to one of a plurality of paths, respectively, to provide physical separation of the plurality of paths from each other, and configured to provide impedance matching for each of the plurality of paths, wherein

the physical separation of the plurality of paths and the impedance matching for each of the plurality of paths provide isolation among the plurality of paths, and relax rejection considerations on filters coupled to the plurality of paths.

27. The communication system of claim 26 , wherein

the plurality of antennas including the one or more multi-feed antennas are configured to provide multiple communication links to be selected according to a priority that a user has or a country where the user is located.

28. The communication system of claim 26 , wherein

the impedance matching is reconfigured to reduce coupling and correlation among the plurality of antennas to improve the isolation.

29. The communication system of claim 26 , wherein

the plurality of paths comprise one or more first paths for processing first signals and one or more second paths for processing second signals;

the one or more first paths are coupled respectively to one or more PAs for amplifying the first signals; and

the one or more second paths are coupled respectively to one or more LNAs for amplifying the second signals.

30. The communication system of claim 28 , wherein

the impedance matching is configured to optimize efficiency of the one or more PAs and the one or more LNAs.

31. The communication system of claim 26 , wherein

the isolation reduces a power leak from one path to another.

32. The communication system of claim 30 , wherein

the power leak is from at least one of the one or more first paths to at least one of the one or more second paths when the multi-feed antenna transmits the first signals.

33. The communication system of claim 28 , wherein

the one or more first paths are coupled respectively to one or more first phase shifters; and

the one or more second paths are coupled respectively to one or more second phase shifters,

wherein

the one or more first phase shifters are configured to adjust phases of the first signals and the one or more second phase shifters are configured to adjust phases of the second signals to improve the impedance matching to increase the isolation.

34. The communication system of claim 32 , wherein

at least one of the one or more first phase shifters and the one or more second phase shifters is configured to be part of the multi-feed antenna.