Matching circuits for phase change material switches
Circuits and methods that provide wider bandwidth and smaller IM inductances for phase change material (PCM) based RF switch networks. The present invention recognizes that it is beneficial to consider the total high parasitic capacitance to ground of the various PCM switches in an RF switch network as constituting two or more separate capacitive contributions. This leads to several “split capacitance” concepts, including signal-path splitting, switch-block splitting, stacked-switch splitting, and splitting parasitic capacitances due to layout discontinuities, in which compensating impedance matching inductances are inserted between additive capacitances.
1. A radio frequency switch network having a split signal-path impedance matching network, including:
(a) a common terminal;
(b) at least two branches, each branch including:
(1) a first inductor coupled to the common terminal;
(2) a second inductor coupled to a corresponding signal terminal; and
(3) a series-shunt phase change material switch block coupled between the first inductor and the second inductor, and connected to a reference voltage;
wherein each branch defines a switchable signal path between the common terminal and the corresponding signal terminal.
2. The invention of claim 1 , wherein each series-shunt phase change material (PCM) switch block includes:
(a) a series PCM switch including first and second ports; and
(b) a shunt PCM switch including first and second ports, the first port of the shunt PCM switch coupled to the first port of the series PCM switch and the second port of the shunt PCM switch configured to be coupled to a reference voltage.
3. The invention of claim 1 , wherein at least one series-shunt phase change material (PCM) switch block includes:
(a) a series PCM switch including first and second ports and comprising a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) a shunt PCM switch including first and second ports and comprising a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM, the first port of the shunt PCM switch coupled to the first port of the series PCM switch and the second port of the shunt PCM switch configured to be coupled to a reference voltage.
4. The invention of claim 1 , wherein at least one series-shunt phase change material switch block includes:
(a) a series PCM switch including first and second ports and comprising a stack of two or more PCM switch components coupled in series between the first and second ports and at least one inductor coupled in series between a pair of adjacent PCM switch components; and
(b) a shunt PCM switch including first and second ports and comprising a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM, the first port of the shunt PCM switch coupled to the first port of the series PCM switch and the second port of the shunt PCM switch configured to be coupled to a reference voltage.
5. A radio frequency switch network having a split-block impedance matching network, including:
(a) a common terminal;
(b) at least two branches, each branch including:
(1) a first inductor coupled to a corresponding signal terminal;
(2) a series phase change material (PCM) switch coupled between the common terminal and the first inductor; and
(3) a shunt PCM switch including first and second ports, the first port coupled between the first inductor and the corresponding signal terminal of the branch, and the second port configured to be coupled to a reference voltage.
6. The invention of claim 5 , further including an inductor coupled between the common terminal and the series PCM switch of the at least two branches.
7. The invention of claim 6 , wherein:
(a) at least one series PCM switch includes first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one shunt PCM switch includes a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM switch.
8. The invention of claim 6 , wherein at least one series PCM switch includes:
(a) first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one inductor coupled in series between a pair of adjacent PCM switch components.
9. The invention of claim 5 , each branch further including a second inductor coupled between the first port of the shunt PCM switch and the corresponding signal terminal of the branch.
10. The invention of claim 9 , wherein:
(a) at least one series PCM switch includes first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one shunt PCM switch includes a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM switch.
11. The invention of claim 9 , wherein at least one series PCM switch includes:
(a) first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one inductor coupled in series between a pair of adjacent PCM switch components.
12. The invention of claim 5 , further including:
(a) a first added inductor coupled between the common terminal and the series PCM switch of the at least two branches; and
(b) a second added inductor coupled between the first port of the shunt PCM switch and the corresponding signal terminal of the branch.
13. The invention of claim 12 , wherein:
(a) at least one series PCM switch includes first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one shunt PCM switch includes a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM switch.
14. The invention of claim 12 , wherein at least one series PCM switch includes:
(a) first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one inductor coupled in series between a pair of adjacent PCM switch components.
15. The invention of claim 5 , wherein:
(a) at least one series PCM switch includes first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one shunt PCM switch includes a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM switch.
16. The invention of claim 5 , wherein at least one series PCM switch includes:
(a) first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one inductor coupled in series between a pair of adjacent PCM switch components.
17. A radio frequency switch network having a split signal-path and a split-block impedance matching network, including:
(a) a common terminal;
(b) at least two branches, each branch including:
(1) a first inductor coupled to the common terminal;
(2) a second inductor coupled to a corresponding signal terminal;
(3) a series phase change material (PCM) switch coupled between the first inductor and the second inductor; and
(4) a shunt PCM switch including first and second ports, the first port coupled between the second inductor and the corresponding signal terminal of the branch, and the second port of the shunt PCM switch configured to be coupled to a reference voltage.
18. The invention of claim 17 , each branch further including a third inductor coupled between the first port of the shunt PCM switch and the corresponding signal terminal of the branch.
19. The invention of claim 17 , wherein:
(a) at least one series PCM switch includes first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one shunt PCM switch includes a stack of two or more PCM switch components coupled in series between the first and second ports of the shunt PCM switch.
20. The invention of claim 17 , wherein at least one series PCM switch includes:
(a) first and second ports and a stack of two or more PCM switch components coupled in series between the first and second ports; and
(b) at least one inductor coupled in series between a pair of adjacent PCM switch components.