US 8,412,292 B2 · IMD-selective design of HTS-based filters

Abstract

Intermodulation distortion (IMD) is known to be an impediment to progress in superconductor-based filter technology. The present invention's methodology for reducing IMD can open doors to heretofore unseen practical applications involving high temperature superconductor (HTS) filters. Typical inventive practice includes (a) increasing the thickness d, and/or (b) changing the operation temperature T, of the filter's HTS film. The film's thickness d is increased in such a way as to decrease the IMD power PIMD in accordance with the material-independent proportionate relationship PIMD∝1/d1.5-6. The film's operation temperature T is bettered or optimized in accordance with the material-independent proportionate relationship PIMD∝(λO(T))10(K(2)(T))2/(ΔO(T))6, and further in accordance with three individual material-dependent relationships, namely, between operation temperature T and each of linear penetration depth λO, gap maximum ΔO, and kernel K(2). Some inventive embodiments include oxygen overdoping of the film as an additional/alternative IMD-reductive measure.

Claims6

Dependent claims

A method for designing electronic apparatus that includes superconductor film, the method comprising:

measuring a first pair of values, said first pair of values being a first power PIMD-1 and a first thickness d1, said first power PIMD-1 being the power of intermodulation distortion characterizing a reference electric apparatus, said first thickness d1 being the thickness of superconductor film that said reference electric apparatus includes;
selecting a second pair of values, said second pair of values being a second power PIMD-2 and a second thickness d2, said second power PIMD-2 being a power of intermodulation distortion characterizing a design electric apparatus and being less than said first power PIMD-1, said second thickness d2 being a thickness of superconductor film that said design electric apparatus includes and being greater than said first thickness d1, said selecting of said second pair of values including performing calculation in accordance with the equation
(PIMD-1)(d1)x=(PIMD-2)(d2)x,
said performing calculation including establishing a value of x between 1.5 and 6.

1 more element

A method for designing electronic apparatus that includes superconductor film, the method comprising:

measuring a first pair of values, said first pair of values being a first power PIMD-1 and a first operation temperature T1, said first power PIMD-1 being the power of intermodulation distortion characterizing a reference electric apparatus, said first operation temperature T1 being the unchanged operation temperature T of said superconductor film that said reference electric apparatus includes;
selecting a second pair of values, said second pair of values being a second power PIMD-2 and a second operation temperature T2, said second power PIMD-2 being a power of intermodulation distortion characterizing a design electric apparatus and being less than said first power PIMD-1, said second operation temperature T2 being an operation temperature T of said superconductor film that said design electric apparatus includes and being different from said first operation temperature T1, said selecting of said second pair of values including performing calculation in accordance with the equation
(PIMD-1)(ΔO(T1))6(λO(T2))10(K(2)(T2))2=(PIMD-2)(ΔO(T2))6(λO(T1))10(K(2)(T1))2;
wherein:
K
(
2
)
⁡
(
T
)
=
q
S
4
⁢
αμ
2
⁢
k
F
⁡
(
c
^
)
π
3
⁢
β
⁢
⁢
m
ab
⁢
c
2
⁡
(
ℏ
⁢
⁢
c
)
2
⁢
∑
n
=
-
∞
∞
⁢
∫
0
2
⁢
π
⁢
ⅆ
θ
⁡
(
cos
4
⁢
θ
)
⁢
(
cos
2
⁢
2
⁢
θ
)
⁢
(
cos
2
⁢
2
⁢
θ
-
(
2
⁢
ℏω
n
/
Δ
0
⁡
(
T
)
)
2
)
(
cos
2
⁢
2
⁢
θ
+
(
ℏω
n
/
Δ
0
⁡
(
T
)
)
2
)
7
/
2
;
qs is the charge of a single carrier;
α≈2 is a dimensionless geometrical factor;
β=1/(kBT);
kB is the Boltzman constant;
c is the speed of light;
ℏ=h/(2π);
h is Planck's constant;
ωn=((2n+1)π)/(βℏ);
n is a positive or negative integer;
λO(T) is the linear penetration depth at operation temperature T;
ΔO(T) is the gap maximum at operation temperature T;
μ is the Fermi energy;
kF(ĉ) is the Fermi momentum in the ĉ crystal-axis direction;
mab is the effective mass in the ab crystal plane.

138 more elements

Dependencies are inferred from the claim text.

IMD-selective design of HTS-based filters

Life of this patent

IMD-selective design of HTS-based filters

Life of this patent

Abstract

Claims6