Extending the Inductor Operating Frequency for Optimally...
Transcript of Extending the Inductor Operating Frequency for Optimally...
![Page 1: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/1.jpg)
Extending the Inductor Operating Frequencyfor Optimally-coupled
Wireless Power Transfer Systems
Fabian L. Cabrera, Renato S. Feitoza and F. Rangel de [email protected], [email protected], [email protected]
RFLaboratorio de RadiofrequenciaUniversidade Federal de Santa Catarina
IMOC 2015
![Page 2: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/2.jpg)
RF Introduction
Inductive linksI Used to wireless powering IMD (implanted medical devices) and
RFID tags.
I The secondary inductor must be miniaturized.I The primary size constraints are more relaxed.
Slide 2
![Page 3: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/3.jpg)
RF Introduction
Inductive linksI Used to wireless powering IMD (implanted medical devices) and
RFID tags.
I The secondary inductor must be miniaturized.I The primary size constraints are more relaxed.
Slide 2
![Page 4: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/4.jpg)
RF Introduction
Inductive linksI Used to wireless powering IMD (implanted medical devices) and
RFID tags.I The secondary inductor must be miniaturized.
I The primary size constraints are more relaxed.
Slide 2
![Page 5: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/5.jpg)
RF Introduction
Inductive linksI Used to wireless powering IMD (implanted medical devices) and
RFID tags.I The secondary inductor must be miniaturized.I The primary size constraints are more relaxed.
Slide 2
![Page 6: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/6.jpg)
RF Power transfer efficiency
Efficiency must be maximized
1η
=1k2 .
1Q1
.1
Q2. (p + 2 +
1p
) + p + 1︸ ︷︷ ︸
I Coupling factor squaredI First Inductor quality factorI Second Inductor quality factorI Load matching dependence
Slide 3
![Page 7: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/7.jpg)
RF Power transfer efficiency
Efficiency must be maximized
1η
=1k2 .
1Q1
.1
Q2. (p + 2 +
1p
) + p + 1︸ ︷︷ ︸I Coupling factor squared
I First Inductor quality factorI Second Inductor quality factorI Load matching dependence
Slide 3
![Page 8: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/8.jpg)
RF Power transfer efficiency
Efficiency must be maximized
1η
=1k2 .
1Q1
.1
Q2. (p + 2 +
1p
) + p + 1︸ ︷︷ ︸I Coupling factor squaredI First Inductor quality factor
I Second Inductor quality factorI Load matching dependence
Slide 3
![Page 9: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/9.jpg)
RF Power transfer efficiency
Efficiency must be maximized
1η
=1k2 .
1Q1
.1
Q2. (p + 2 +
1p
) + p + 1︸ ︷︷ ︸I Coupling factor squaredI First Inductor quality factorI Second Inductor quality factor
I Load matching dependence
Slide 3
![Page 10: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/10.jpg)
RF Power transfer efficiency
Efficiency must be maximized
1η
=1k2 .
1Q1
.1
Q2. (p + 2 +
1p
) + p + 1︸ ︷︷ ︸I Coupling factor squaredI First Inductor quality factorI Second Inductor quality factorI Load matching dependence
Slide 3
![Page 11: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/11.jpg)
RF Mutual coupling model
k = M/√
L1L2
M = µ
√davg1davg2
π
[(2γ− γ)
K(γ)− 2γ
E(γ)
](1)
γ =
√4davg1davg2
(davg1 + davg2)2 + πd2 , (2)
1 10 10010
−3
10−2
10−1
davg1
[mm]
k
d=5mm
d=15mm
d=25mm
Magnetic coupling factor when davg2 = 4 mm. Slide 4
![Page 12: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/12.jpg)
RF Quality factor model
L
R(f)C
10M 100M 1G
10−1
100
101
f [Hz]
R [
Ω]
Radiation
R ∝ f 4
Skin effect
R ∝ f 0.5
Loss factor
Λ =1Q
=R
2πf L
0.01 0.1 1
0.01
0.1
f [GHz]
Λ
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
Sim. Model
Slide 5
![Page 13: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/13.jpg)
RF Quality factor model
L
R(f)C
10M 100M 1G
10−1
100
101
f [Hz]
R [
Ω]
Radiation
R ∝ f 4
Skin effect
R ∝ f 0.5
Loss factor
Λ =1Q
=R
2πf L
0.01 0.1 1
0.01
0.1
f [GHz]
Λ
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
Sim. Model
Slide 5
![Page 14: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/14.jpg)
RF Quality factor model
L
R(f)C
10M 100M 1G
10−1
100
101
f [Hz]
R [
Ω]
Radiation
R ∝ f 4
Skin effect
R ∝ f 0.5
Loss factor
Λ =1Q
=R
2πf L
0.01 0.1 1
0.01
0.1
f [GHz]
Λ
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
davg1
=4 mm
davg1
=10 mm
davg1
=22 mm
Sim. Model
Slide 5
![Page 15: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/15.jpg)
RF Trade-off
To maximize efficiency:I k must be maximized, this leads to a primary inductor bigger
than the secondary.
I Operating frequency is then limited by the biggest inductor.I Therefore, the smaller inductor does not operate in its optimal
frequency.I We can extend the operating frequency of the link using a
segmented inductor.
Slide 6
![Page 16: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/16.jpg)
RF Trade-off
To maximize efficiency:I k must be maximized, this leads to a primary inductor bigger
than the secondary.I Operating frequency is then limited by the biggest inductor.
I Therefore, the smaller inductor does not operate in its optimalfrequency.
I We can extend the operating frequency of the link using a
segmented inductor.
Slide 6
![Page 17: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/17.jpg)
RF Trade-off
To maximize efficiency:I k must be maximized, this leads to a primary inductor bigger
than the secondary.I Operating frequency is then limited by the biggest inductor.I Therefore, the smaller inductor does not operate in its optimal
frequency.
I We can extend the operating frequency of the link using a
segmented inductor.
Slide 6
![Page 18: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/18.jpg)
RF Trade-off
To maximize efficiency:I k must be maximized, this leads to a primary inductor bigger
than the secondary.I Operating frequency is then limited by the biggest inductor.I Therefore, the smaller inductor does not operate in its optimal
frequency.I We can extend the operating frequency of the link using a
segmented inductor.
Slide 6
![Page 19: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/19.jpg)
RF Segmented inductor
L
RS (f,CS)C
CS
CS =CG + CD
N − 1
CG Gap capacitanceCD Discrete capacitorN Number of segments
0.1 1
−600
−400
−200
0
200
400
600
f [GHz]
X [
Ω]
N = 1
N = 2
N = 4
N = 8
0.1 1
0.1
1
10
f [GHz]
RS [
Ω]
N=1
N=4, CD
= 0.5 pF
N=4, CD
= 2 pF
N=4, CD
= 8 pF
(a) Equivalent reactance when CD=0. (b) Segmented inductor losses.
Slide 7
![Page 20: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/20.jpg)
RF Segmented inductor
L
RS (f,CS)C
CS
CS =CG + CD
N − 1
CG Gap capacitanceCD Discrete capacitorN Number of segments
0.1 1
−600
−400
−200
0
200
400
600
f [GHz]
X [
Ω]
N = 1
N = 2
N = 4
N = 8
0.1 1
0.1
1
10
f [GHz]
RS [
Ω]
N=1
N=4, CD
= 0.5 pF
N=4, CD
= 2 pF
N=4, CD
= 8 pF
(a) Equivalent reactance when CD=0. (b) Segmented inductor losses.
Slide 7
![Page 21: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/21.jpg)
RF Segmented inductor
L
RS (f,CS)C
CS
CS =CG + CD
N − 1
CG Gap capacitanceCD Discrete capacitorN Number of segments
0.1 1
−600
−400
−200
0
200
400
600
f [GHz]
X [
Ω]
N = 1
N = 2
N = 4
N = 8
0.1 1
0.1
1
10
f [GHz]
RS [
Ω]
N=1
N=4, CD
= 0.5 pF
N=4, CD
= 2 pF
N=4, CD
= 8 pF
(a) Equivalent reactance when CD=0. (b) Segmented inductor losses.Slide 7
![Page 22: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/22.jpg)
RF Segmented inductor quality factor
0.1 1
100
200
300
400
f [GHz]
Q1
1
2 0~16 pF
4 1~16 pF
8 2~32 pF
N
CD
0.1 11
2
3
4
5
6
7
x 10
f [GHz]Q
1Q
2
1
2 0~16 pF
4 1~16 pF
8 2~32 pF
N
CD
x104
Slide 8
![Page 23: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/23.jpg)
RF Effect of the capacitor losses
1 10
0.1
1
C [pF]
ES
R [
Ω]
2 GHz
1 GHz
250 MHz
2 GHz
1 GHz
250 MHz
Data Fitted
0.1 1
1
2
3
f [GHz]
Q1Q
2
1
2 0~16 pF
4 1~16 pF
8 2~32 pF
N
CD
x104
(a) Equivalent series resistance for discrete capacitors. (b) Quality factorsproduct accounting the capacitors ESR.
I Performance is no longer improved for higher values of N because ofthe capacitor losses.
Slide 9
![Page 24: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/24.jpg)
RF Implementation
davg2 [mm] davg1 [mm] N CD [pF] d [mm]4 22 4 3 15
Slide 10
![Page 25: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/25.jpg)
RF Experimental results
N CD [pF] ηmax [%] fηmax [MHz]1 – 30 415 Meas. [3]4 3 38 735 Sim.4 1.5 37 990 Sim.4 1.5 30 980 Meas.
[3] Fabian L. Cabrera and F. Rangel de Sousa, “Optimal Design of Energy Efficient
Inductive Links for Powering Implanted Devices,”in BioWireleSS 2014.Slide 11
![Page 26: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/26.jpg)
RF Conclusions
Conclusions:I The operating frequency of an optimally-coupled inductive link
was extended from 415MHz to 980 MHz.
I The extension of the operating frequency was achieved bydividing the primary inductor into four segments.
I The technique presented offers potential improvements on thelink efficienncy, however that improvements are limited by thecapacitor losses.
I The extension of the primary inductor frequency offers flexibilityto the inductive link design.
Slide 12
![Page 27: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/27.jpg)
RF Conclusions
Conclusions:I The operating frequency of an optimally-coupled inductive link
was extended from 415MHz to 980 MHz.I The extension of the operating frequency was achieved by
dividing the primary inductor into four segments.
I The technique presented offers potential improvements on thelink efficienncy, however that improvements are limited by thecapacitor losses.
I The extension of the primary inductor frequency offers flexibilityto the inductive link design.
Slide 12
![Page 28: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/28.jpg)
RF Conclusions
Conclusions:I The operating frequency of an optimally-coupled inductive link
was extended from 415MHz to 980 MHz.I The extension of the operating frequency was achieved by
dividing the primary inductor into four segments.I The technique presented offers potential improvements on the
link efficienncy, however that improvements are limited by thecapacitor losses.
I The extension of the primary inductor frequency offers flexibilityto the inductive link design.
Slide 12
![Page 29: Extending the Inductor Operating Frequency for Optimally ...lrf.ufsc.br/files/2015/11/RianoIMOC2015_ppt.pdf · Extending the Inductor Operating Frequency for Optimally-coupled Wireless](https://reader034.fdocuments.us/reader034/viewer/2022051507/5a7130017f8b9a93538cbb97/html5/thumbnails/29.jpg)
RF Conclusions
Conclusions:I The operating frequency of an optimally-coupled inductive link
was extended from 415MHz to 980 MHz.I The extension of the operating frequency was achieved by
dividing the primary inductor into four segments.I The technique presented offers potential improvements on the
link efficienncy, however that improvements are limited by thecapacitor losses.
I The extension of the primary inductor frequency offers flexibilityto the inductive link design.
Slide 12