# US 10,122,329 B2 · Matching circuit for low noise amplifier and low noise amplifier comprising such a circuit

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- Number: US 10,122,329 B2
- Document ID: US10122329B2
- Status: Granted
- Kind: B2
- Application number: 15/699,376
- Filed: 2017-09-08
- Published: 2018-03-15
- Granted: 2018-11-06
- Earliest claimed: 2016-09-09
- Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Applicants: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Inventors: Max Hofheinz; Salha Jebari
- Web page: https://patentgrep.com/patent/US10122329B2

## CPC

- H03F 1/565: {using inductive elements}
- H03F 1/56: Modifications of input or output impedances, not otherwise provided for
- H03F 3/19: with semiconductor devices only
- H03F 3/608: {Reflection amplifiers, i.e. amplifiers using a one-port amplifying element and a multiport coupler (H03F7/00 takes precedence)}
- H03F 7/00: Parametric amplifiers
- H03F 19/00: Amplifiers using superconductivity effects
- H03F 2200/294: the amplifier being a low noise amplifier [LNA]
- H03F 2200/387: A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
- H03F: AMPLIFIERS

## Abstract

An impedance matching circuit be connected to a non-linear impedance including a superconductor, includes a first terminal designated first connection port to be connected to a first connector of the non-linear impedance, a second terminal designated second connection port to be connected to a second connector of the non-linear impedance, a third terminal designated input/output terminal to receive the signal to amplify and a fourth terminal designated supply terminal to be connected to a polarisation source and configured so that a voltage V is applied between the first connection port and the second connection port. The circuit further includes a plurality of passive electrical components.

## Claims

### Claim 1

An impedance matching circuit intended to be connected to a non-linear impedance comprising a superconductor, said circuit comprising:
a first terminal designated first connection port configured to be connected to a first connector of the non-linear impedance;
a second terminal designated second connection port configured to be connected to a second connector of the non-linear impedance;
a third terminal designated input/output terminal configured to receive a signal to amplify with a gain in power G and a pass band BW;
a fourth terminal designated supply terminal configured to be connected to a polarisation source and configured so that a voltage V is applied between the first connection port and the second connection port, and
a plurality of passive electrical components configured such that the impedance Z(f) between the first connection port and the second connection port for a signal of frequency f has a real part Re(Z(f)) such that:
Re(Z(fs))>0 with fs a first frequency designated frequency of the signal;
Re(Z(fi))>0 with fi a second frequency designated idler frequency;
Re
⁡
(
Z
⁡
(
0
)
)
<
h
4
⁢
⁢
e
2
⁢
f
p
G
·
BW
with fp a third frequency designated pump frequency;
Re
⁡
(
Z
⁡
(
f
p
+
f
s
)
)
<
f
p
+
f
s
f
i
⁢
Re
⁡
(
Z
⁡
(
f
i
)
)
;
the pump frequency being chosen such that nfp=fs+fi with n an integer belonging to [1, +∞] and the idler frequency being chosen such that
f
i
>
k
B
⁢
T
h
with T the temperature of the circuit, kB Boltzmann's constant and h Planck's constant.

### Claim 2 (depends on 1)

The circuit according to claim 1, wherein
Re
⁡
(
Z
⁡
(
f
p
+
f
s
)
)
<
Re
⁡
(
Z
⁡
(
f
i
)
)
10
.

### Claim 3 (depends on 1)

The circuit according to claim 1, wherein
Re
⁡
(
Z
⁡
(
0
)
)
<
h
4
⁢
⁢
e
2
⁢
1
10
⁢
⁢
G
.

### Claim 4 (depends on 1)

The circuit according to claim 1, wherein
Re
⁡
(
Z
⁡
(
f
p
)
)
<
4
⁢
⁢
e
2
h
⁢
BW
⁢
f
p
f
s
·
f
i
⁢
Re
⁡
(
Z
⁡
(
f
s
)
)
⁢
Re
⁡
(
Z
⁡
(
f
i
)
)
.

### Claim 5 (depends on 1)

The circuit according to claim 1, wherein the input/output terminal is intended to be connected to an impedance of value Z0 and
Re
⁡
(
Z
⁡
(
f
s
)
)
<
2
⁢

Z
trans
⁡
(
f
s
)

2
Z
0
with Ztrans(fs) the voltage at the level of the input/output terminal when a unit current of frequency fs is applied between the first connection port and the second connection port.

### Claim 6 (depends on 1)

The circuit according to claim 1, wherein
Re
⁡
(
Z
⁡
(
f
p
+
f
s
)
)
<
f
p
+
f
i
f
s
⁢
Re
⁡
(
Z
⁡
(
f
s
)
)
.

### Claim 7 (depends on 1)

The circuit according to claim 1, wherein
f
i
>
4
⁢
k
B
⁢
T
h
.

### Claim 8 (depends on 1)

The circuit according to claim 1, wherein n=1.

### Claim 9 (depends on 1)

The circuit according to claim 1, wherein
max
⁢
{
Re
⁡
(
Z
⁡
(
f
s
)
)
,
Re
⁡
(
Z
⁡
(
f
i
)
)
}
<
h
4
⁢
⁢
e
2
.

### Claim 10 (depends on 1)

The circuit according to claim 1, wherein the plurality of passive electrical components comprises:
a first waveguide segment of which a first end is connected to the supply terminal through an inductance and to the input/output terminal through a first capacitance and a second end is connected to the first connection port;
a second waveguide segment of which a first end is connected to earth through a second capacitance and a second end is connected to the first connection port;
a third waveguide segment of which a first end is connected to an infinite impedance and a second end is connected to the first connection port;
and wherein the second connection port is connected to earth.

### Claim 11 (depends on 1)

A reflection amplifier comprising an impedance matching circuit according to claim 1, a polarisation source connected to the supply terminal, a non-linear impedance comprising a superconductor, said non-linear impedance comprising a first connector and a second connector, the first connector of the impedance being connected to the first connection port of the matching circuit, the second connector of the impedance being connected to the second connection port of the matching circuit, wherein the voltage applied between the first connection terminal and the second connection terminal by means of the voltage source is chosen such that
f
p
=
2
⁢
⁢
eV
h
with 2e the electric charge of a Cooper pair and h Planck's constant.

### Claim 12 (depends on 11)

The amplifier according to claim 11, wherein the superconductor material of the non-linear impedance is chosen such that
f
s
<
2
⁢
⁢
Δ
h
with Δ the superconductor gap of the superconductor.

### Claim 13 (depends on 11)

The amplifier according to claim 11, wherein the non-linear impedance comprises a Josephson junction.

### Claim 14 (depends on 13)

The amplifier according to claim 13, wherein the Josephson junction is of Superconductor/Insulator/Superconductor type.

### Claim 15 (depends on 11)

The amplifier according to claim 11, wherein the non-linear superconducting impedance comprises a SQUID.