High throw-count RF switch
A high throw-count multiple-pole FET-based RF switch architecture that provides good RF performance in terms of insertion loss, return loss, isolation, linearity, and power handling. A common port RFC is coupled along a common path to multiple ports RFn. Embodiments introduce additional common RF path branch isolation switches which are controlled by state dependent logic. The branch isolation switches help to isolate the unused branch ports RFn and the unused portion of the common path from the active portion of the common path, and thereby reduce the reactive load attributable to such branches that degrades RF performance of the ports RFn “closer” to the common port RFC. The branch isolation switches can also be used to reconfigure the switch architecture for a multiplex function as well as separate switch path banks for re-configurability of purpose, tuning, or varying switch throw counts and packaging options.
1. An RF switch including:
(a) a plurality of ports each coupled to a common path through a series-shunt switching element; and
(b) at least one series isolation switch each connected along the common path between a corresponding two sets of ports and configured to selectively connect or isolate the corresponding two sets of ports and configured to enable a first selected port to be coupled to a second selected port through the common path, with any series isolation switches between the first and second selected ports set to a conducting state and all other series isolation switches set to a blocking state.
2. The RF switch of claim 1 , wherein the RF switch allows connection of any one port to any other port.
3. The RF switch of claim 1 , wherein at least one port is a common port and at least one other port is a signal port.
4. The RF switch of claim 1 , wherein at least one series isolation switch includes a series-shunt switch.
5. The RF switch of claim 1 , wherein at least one series-shunt switching element is a high-isolation series-shunt switching element.
6. An RF switch including:
(a) a plurality of ports each coupled to a common path through a series-shunt switching element;
(b) a common port coupled to the common path; and
(c) at least one series isolation switch each connected along the common path between a corresponding two sets of ports and configured to selectively connect or isolate the corresponding two sets of ports and configured to enable a selected port of a first set of ports to be coupled to the common port through the common path, with any isolation switches between the selected port and the common port set to a conducting state and all other isolation switches set to a blocking state.
7. The RF switch of claim 6 , wherein the common port is unconnected and the RF switch is reconfigurable to operate as a matrix switch allowing connection of any one port to any other port.
8. The RF switch of claim 6 , wherein at least one series isolation switch includes a series-shunt switch.
9. The RF switch of claim 6 , wherein at least one series-shunt switching element is a high-isolation series-shunt switching element.
10. The RF switch of claim 6 , further including a termination circuit operatively coupled to the common port.
11. An RF switch including:
(a) at least one common path;
(b) at least one common port coupled to the at least one common path;
(c) at least three sections each containing at least one signal port coupled to at least one common path through a series-shunt switching element; and
(d) at least two isolation switches each connected to at least one common path between two corresponding adjacent sections, each isolation switch including at least one series switch configured to selectively connect or isolate the two corresponding adjacent sections;
wherein when a selected signal port is coupled to at least one common port through at least one common path, any isolation switches between the selected signal port and the at least one common port are configured in a conducting state.
12. The RF switch of claim 11 , wherein when the selected signal port is coupled to at least one common port through at least one common path, any isolation switches between the selected signal port and the at least one common port are configured in a conducting state and all other isolation switches are configured in a blocking state.
13. The RF switch of claim 11 , wherein at least one common port of the at least one common port is coupled between the ends of two of the common paths to define at least two groups of sections.
14. The RF switch of claim 11 , wherein at least one isolation switch series switch has a first terminal and a second terminal each connected to corresponding adjacent sections, and further including a shunt switch coupled between the first terminal and circuit ground.
15. The RF switch of claim 14 , wherein at least one isolation switch series switch has a first terminal and a second terminal each connected to corresponding adjacent sections, and further including a shunt switch coupled between the second terminal and circuit ground.
16. The RF switch of claim 11 , wherein the at least one series switch comprises one or more series-connected FETs.
17. The RF switch of claim 11 , wherein at least one series-shunt switching element comprises (1) a series FET coupled between a corresponding signal port and one of the at least one common path, and (2) a shunt FET coupled between such corresponding signal port and circuit ground.
18. The RF switch of claim 11 , wherein each common port is unconnected and the RF switch is configured to operate as a matrix switch allowing connection of a selected signal port to any of a selected group of other signal ports.
19. The RF switch of claim 11 , wherein at least one series-shunt switching element is a high-isolation series-shunt switching element.
20. The RF switch of claim 11 , further including a termination circuit operatively coupled to the common port.