Radio frequency filtering circuitry
RF filtering circuitry includes a common node, a first input/output node, a second/input output node, a first filter coupled between the common node, the first input/output node, and the second input/output node, and a second filter coupled between the common node, the first input/output node, and the second input/output node. The first filter is configured to provide a first bandpass filter response between the common node and the first input/output node, where the first bandpass filter response is configured to pass RF signals within a first subset of the first frequency band while attenuating other signals. Further, the first filter is configured to provide a bandstop filter response between the common node and the second input/output node, where the bandstop filter response is configured to attenuate RF signals within the first subset of the first frequency band while passing other signals.
1. Radio frequency (RF) filtering circuitry comprising:
a common node;
a first input/output node associated with RF signals within a first frequency band;
a second input/output node associated with RF signals within a second frequency band;
a first filter coupled between the common node, the first input/output node, and the second input/output node and configured to:
provide a first bandpass filter response between the common node and the first input/output node, the first bandpass filter response configured to pass RF signals within at least a portion of a first subset of the first frequency band while attenuating other signals; and
provide a bandstop filter response between the common node and the second input/output node, the bandstop filter response configured to attenuate RF signals within at least a portion of the first subset of the first frequency band while passing other signals; and
a second filter coupled between the common node, the first input/output node, and the second input/output node and configured to:
provide a second bandpass filter response between the common node and the first input/output node, the second bandpass filter response configured to pass RF signals within a second subset of the first frequency band while attenuating other signals, wherein the first subset of the first frequency band and the second subset of the first frequency band encompass the first frequency band; and
provide a third bandpass filter response between the common node and the second input/output node, the third bandpass filter response configured to pass RF signals within the second frequency band while attenuating other signals.
2. The RF filtering circuitry of claim 1 wherein the first filter comprises one or more acoustic filtering elements.
3. The RF filtering circuitry of claim 2 wherein the first filter is a hybrid acoustic and lumped element filter.
4. The RF filtering circuitry of claim 2 wherein the one or more acoustic filtering elements are one of a bulk acoustic wave (BAW) filtering element and a surface acoustic wave (SAW) filtering element.
5. The RF filtering circuitry of claim 2 wherein a quotient of a frequency delta between the first frequency band and the second frequency band over a bandwidth of a passband of the first bandpass filter response is less than or equal to 1.5.
6. The RF filtering circuitry of claim 5 wherein the second filter is one of an acoustic filter and a lumped element filter.
7. The RF filtering circuitry of claim 2 wherein the second filter is one of an acoustic filter and a lumped element filter.
8. The RF filtering circuitry of claim 1 further comprising switching circuitry coupled between the common node and the first filter, the first input/output node and the first filter, the second input/output node and the first filter, the common node and the second filter, the first input/output node and the second filter, and the second input/output node and the second filter.
9. The RF filtering circuitry of claim 8 further comprising switching control circuitry configured to operate the switching circuitry such that:
in a first mode of operation of the RF filtering circuitry, the first filter is coupled between the common node, the first input/output node, and the second input/output node while the second filter is isolated from the common node, the first input/output node, and the second input/output node; and
in a second mode of operation of the RF filtering circuitry, the first filter is isolated from the common node, the first input/output node, and the second input/output node while the second filter is coupled between the common node, the first input/output node, and the second input/output node.
10. The RF filtering circuitry of claim 8 wherein the switching circuitry is further coupled between the common node and the first input/output node and the common node and the second input/output node.
11. The RF filtering circuitry of claim 10 further comprising switching control circuitry configured to operate the switching circuitry such that:
in a first mode of operation of the RF filtering circuitry, the first filter is coupled between the common node, the first input/output node, and the second input/output node while the second filter is isolated from the common node, the first input/output node, and the second input/output node;
in a second mode of operation of the RF filtering circuitry, the first filter is isolated from the common node, the first input/output node, and the second input/output node while the second filter is coupled between the common node, the first input/output node, and the second input/output node; and
in a third mode of operation of the RF filtering circuitry, the common node is directly coupled to one of the first input/output node and the second input/output node.
12. The RF filtering circuitry of claim 1 wherein the first subset of the first frequency band is separated from the second frequency band by less than a predetermined frequency delta and the second subset of the first frequency band is separated from the second frequency band by more than the predetermined frequency delta.
13. The RF filtering circuitry of claim 12 wherein the predetermined frequency delta is 100 MHz.
14. The RF filtering circuitry of claim 1 wherein the first frequency band is between 2300 MHz and 2700 MHz and the second frequency band is between 1700 MHz and 2200 MHz.
15. The RF filtering circuitry of claim 14 wherein the first subset of the first frequency band is between 2300 MHz and 2400 MHz and the second subset of the first frequency band is between 2496 MHz and 2700 MHz.
16. The RF filtering circuitry of claim 1 further comprising a third input/output node associated with RF signals within a third frequency band and wherein:
the first filter is further configured to provide a fourth bandpass filter response between the common node and the third input/output node, the fourth bandpass filter response configured to pass RF signals within the third frequency band while attenuating other signals; and
the second filter is further configured to provide a fifth bandpass filter response between the common node and the third input/output node, the fifth bandpass filter response configured to pass RF signals within the third frequency band while attenuating other signals.
17. The RF filtering circuitry of claim 16 wherein the first filter is a hybrid acoustic and lumped element filter and the second filter is a lumped element filter.
18. The RF filtering circuitry of claim 16 wherein the first frequency band is between 2300 MHz and 2700 MHz, the second frequency band is between 1700 MHz and 2200 MHz, and the third frequency band is between 699 MHz and 980 MHz.
19. The RF filtering circuitry of claim 18 wherein the first subset of the first frequency band is between 2300 MHz and 2400 MHz and the second subset of the first frequency band is between 2496 MHz and 2700 MHz.