Laminated Conductor Structure
  for RF in Normal Conducting Case


                                       Y. Iwashita, Kyo...
Normal vs Super
                                              Nc                                                       Sc
...
preparation of this paper.
       In this paper we have attempted to present what is                         We are also m...
1+ i         iωt
                                                                                   −(1+i)x
              ...
Current Distribution in Conductor
                                      1+ i             −(1+i)x
                         ...
Current Distribution in Conductor
                                      1+ i             −(1+i)x
                         ...
EM Field in a Thin Foil Conductor
                                           vacuum Y                          vacuum
    ...
Current Distribution
                          Conductor                                                            Conduc...
Current Distribution in a Thin Foil
        1.5                                                                 1.5

     ...
Magnetic Field(current)distribution

                                                                                    C...
Magnetic Field(current)distribution

                                                                                    C...
Example: Dielectric Resonator

                          >>
                                                              ...
Example: Dielectric Resonator

                          >>
                                                              ...
Equivalent Circuit


             E                         B                                 E




                      ...
Equivalent Circuit


             E                         B                                 E




                      ...
Equivalent Circuit


             E                         B                                 E




                      ...
Experiment with coaxial cavity
                                                             (Simple Cavity Structure)

   ...
Inner Conductor

                                                  Outer Conductor




                 PE mesh           ...
Measurements and CFISH

     Length of
     insulated                                                                     ...
Magnetic Field(current)distribution

                                                                  Conductor


       ...
ISSUES
    •When the insulating layers have
           comparable length to the wavelength,
           they form resonator...
Limitations
                                                                                           0.46!c~
           ...
Coax Cavity Case
    CFISH: MLcoax with Lossy Dielectric as conductor 1um F = 2990.32 MHz
    4100                        ...
Possible Configuration




                  C
                  L
                                                        ...
Possible Configuration




                  C
                  L
                                                        ...
Possible Configuration




                  C
                  L
                                                        ...
Summary
          The structure can improve Q on some
          structure.
          The insulating layers should have ope...
Upcoming SlideShare
Loading in …5
×

Iwashita - Laminated conductor structure for rf in normal conducting case

1,120 views

Published on

http://www.surfacetreatments.it/thinfilms

Laminated Conductor Structure for RF in normal conducting case (Yoshihisa Iwashita - 20')
Speaker: Yoshihisa Iwashita - Kyoto University | Duration: 20 min.
Abstract
Laminated conductor structure for RF was proposed by A.M. Clogston in 1951.The motivation was to reduce the skin-effect loss caused by Joule heating.When the currents are well distributed to conductor foils that is thinner than the skin depth, the current density can be reduced and the power dissipation in the conductor can be reduced.This structure, however, has not been practically used, maybe because of some restrictions to apply. When we apply the similar layered structure for superconducting (sc.) surfaces, similar restriction may hit.Some thoughts that may be useful for sc. from the study on normal conducting case will be discussed.

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,120
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
20
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Iwashita - Laminated conductor structure for rf in normal conducting case

  1. 1. Laminated Conductor Structure for RF in Normal Conducting Case Y. Iwashita, Kyoto U. AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  2. 2. Normal vs Super Nc Sc resistance depth E Limit Break down Cold Emission? H Limit Heat (melt?) Hc AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  3. 3. preparation of this paper. In this paper we have attempted to present what is We are also much indebted to J. A. Morton for his known about the circuit performance of n-p-n transis- encouragement and helpful guidance, and to M. Sparks tors. Since these devices are still undergoing exploratory for providing most of the transistors which have been development and since only a limited number have studied. We wish to thank L. 0. Schott, L. C. Geiger, A. M. Clogston, Reduction of Skin-Effect Losses by the Use of been produced, it is obviously impossible to give sta- tistical data on reproducibility or on such reliability and K. D. Smith for taking some of the data presented, and G. Raisbeck and L. G. Schimpf for proofreading and factors as the effect of ambient temperature. correcting the manuscript. Laminated Conductors, Proc. of the IRE, 39-7, July 1951, pp.767-782 Reduction Skin-Effect Losses by the of Use of Laminated Conductors * A. M. CLOGSTONt, SENIOR MEMBER, IRE (Copyright 1951, American Telephone & Telegraph Company) Summary-It has recently been discovered that it is possible to where a is the conductivity of the material, ju is its per- reduce skin effect losses in transmission Iines by properly laminating meability, and X is 2wx times the frequency f under con- the conductors and adjusting the velocity of transmission of the waves. The theory for such laminated transmission lines is pre- sideration. Throughout this paper rationalized mks sented in the case of planar systems for both infinitesimally thin units are used. laminae and laminae of finite thickness. A transmission line com- From one point of view, skin effect serves a most use- pletely filled with lamimated material is discussed. An analysis is ful purpose; for instance, in shielding electrical equip- given of the modes of transmission in a laminated line, and of the ment or reducing cross talk between communication problem of terminating such a line. circuits. On the other hand, the effect severely limits I. INTRODUCTION the high-frequency performance of many types of T HAS LONG been recognized that an electro- electrical apparatus, including in particular the various magnetic wave propagating in the vicinity of an kinds of transmission lines. has been discovered that it electrical conductor can penetrate only a limited is Surprisingly enough, it to increase the distance to possible, within limits, distance into the interior of the material. This phenom- which an electromagnetic wave penetrates into a con- enon is known as "skin effect" and is usually measured is done essentially by by a so-called "skin depth" 6. If y is measured from the ducting conductorThismany insulated laminaefabricat- material. ing the surface of a conductor into its depth, the amplitude ments of conducting material arranged of or fila- of the electromagnetic wave and the accompanying parallel to the current density decreases as e-vJa, provided the con- direction of current flow. If the transverse dimensions ductor is several times 6 in thickness, so that for y=8 skin of the laminae or filaments are small compared to the the amplitude has fallen to 1/e=0.367 times its value depth 8 at the frequency under consideration, and at the surface. The skin depth 8 is given by if the velocity of the electromagnetic wave along the conductor is close to a certain critical value, the wave /2 will penetrate into the composite conductor a distance a- /{/-} ~~~~~(1)great enough to include a thickness of conducting ma- terial many skin depths deep. Physically speaking, the But no product... * This is one of a class of papers published through arrangements lateral change of the wave through the conducting with certain other journals. It is appearing also in the July, 1951, regions is very nearly cancelled by the change through issue of the Bell System Technical Journal. t Bell Telephone Laboratories, Inc., Murray Hill, N. J. the insulating regions. AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  4. 4. 1+ i iωt −(1+i)x j(x) = H z (0)e e δ δ J = ∞j (x) dx = H (0)e iωt ∫ 0 z 2 € ∞ 2 H z (0) ωµ Pbulk = ∫ 0 j σ dx = σδ = 2σ H z (0) 2 € j(x) AccLab BmSci ICR KyotoUniversity 4 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  5. 5. Current Distribution in Conductor 1+ i −(1+i)x iωt δ j(x) = H z (0)e e δ 1.0 Abs(j/jmax) Re(j/jmax) Relative values 0.5 Im(j/jmax) € 0.0 -0.5 0 1 2 3 4 x/δ 5 δ : Skin Depth AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the 5 limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  6. 6. Current Distribution in Conductor 1+ i −(1+i)x iωt δ j(x) = H z (0)e e δ 1.0 Abs(j/jmax) Re(j/jmax) Relative values 0.5 Im(j/jmax) € 0.0 -0.5 0 1 2 3 4 x/δ 5 δ : Skin Depth AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the 5 limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  7. 7. EM Field in a Thin Foil Conductor vacuum Y vacuum Hz=H0eiωt Hz=ξH0eiωt αδ X j(x) = H z (0) j f e ( −(1+i)x /δ – jbe + −(1+i)(αδ −x )/δ ) jf = (1+ i)e (1+i)α (e (1+i)α −ξ ),j = (1 + i)e (1+i)α (ξe (1+i)α −1 ). b € δe ( 2(1+i)α −1 ) δe ( 2(1+i)α −1 ) Superposition of left and right traveling waves. AccLab BmSci ICR KyotoUniversity 6 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  8. 8. Current Distribution Conductor Conductor HL j j HR HL j j HR HL=HR HL>HR Currents cancel each other in-between (simplified schematics ... have to consider phase) AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  9. 9. Current Distribution in a Thin Foil 1.5 1.5 ξ=1 ξ=0.5 ξ=1, α=8 ξ=1, α=1 ξ=1, α=4 ξ=0.5, α=1 1.0 ξ=1, α=2 1.0 ξ=0.5, α=2 ξ=1, α=1.5 ξ=0.5, α=4 ξ=1, α=1 0.5 ξ=1, α=0.5 0.5 Im( j ) Im( j ) Thick Thick 0.0 0.0 -0.5 -0.5 Thin Thin -1.0 -1.0 -1.5 -1.5 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Re( j ) Re( j ) Same B: Zero net Current Half strength at right Thinner→Real part vanishes quickly Thinner→Uniform real part while imaginary part remains Linear in imaginary part Net current in imaginary part is Zero. AccLab BmSci ICR KyotoUniversity 8 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  10. 10. Magnetic Field(current)distribution Conductor Foil Conductor AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  11. 11. Magnetic Field(current)distribution Conductor Foil Conductor How to re-distribute the currents? AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  12. 12. Example: Dielectric Resonator >> 1.50 Ez (r) = Ez (0) J 0 (kr), k = x1' R 1.00 Ez Hθ rHθ 0.50 0.00 -0.50 0 0.5 1 1.5 2 2.5 3 3.5 4 r AccLab BmSci ICR KyotoUniversity 10 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  13. 13. Example: Dielectric Resonator >> 1.50 Ez (r) = Ez (0) J 0 (kr), k = x1' R 1.00 Ez Hθ rHθ r2 0.50 ˙ ∫ r1 D 2πrdr = 0 0.00 -0.50 0 0.5 1 1.5 2 r 2.5 3 3.5 4 Spacer r1 r2 Dielectric R material r € Conductor AccLab BmSci ICR KyotoUniversity 10 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  14. 14. Equivalent Circuit E B E L Raise freq. by reducing L and C C AccLab BmSci ICR KyotoUniversity 11 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  15. 15. Equivalent Circuit E B E L Raise freq. by reducing L and C C AccLab BmSci ICR KyotoUniversity 11 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  16. 16. Equivalent Circuit E B E L Raise freq. by reducing L and C C AccLab BmSci ICR KyotoUniversity 11 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  17. 17. Experiment with coaxial cavity (Simple Cavity Structure) Second Mode has current λ/4 peak at the center Y.Tajima, Y.Iwashita, H.Fujisawa, M.Ichikawa, H.Tongu: Reduction of skin effect RF power loss by a thin conductor foil, JAPANESE JOURNAL OF APPLIED PHYSICS, 47, 4765-4768, 2008 E Z AccLab BmSci ICR KyotoUniversity 12 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  18. 18. Inner Conductor Outer Conductor PE mesh End Plates AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  19. 19. Measurements and CFISH Length of insulated 10% conductor 1.0 CFISH Complex version of SUPERFISH Agrees within a few %. Only 1/4 area was covered. corresponds to 1.4 times local effect n (n=2) AccLab BmSci ICR KyotoUniversity 14 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  20. 20. Magnetic Field(current)distribution Conductor This gap is essential to bring Foil Conductor magnetic flux. AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  21. 21. ISSUES •When the insulating layers have comparable length to the wavelength, they form resonators whose resonances screw up the field distributions. •The stepped gap structure may help it. But when the gap is too narrow, small stored energy leads to low Q. AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  22. 22. Limitations 0.46!c~ !c/2 low Q AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  23. 23. Coax Cavity Case CFISH: MLcoax with Lossy Dielectric as conductor 1um F = 2990.32 MHz 4100 4100 λ/4 4050 Including losses 70% 4050 4000 4000 0 50 100 150 200 250 300 350 400 450 500 FISH: MLcoax with Lossy Dielectric as conductor 1um F = 3003.8031 MHz 4100 4100 4050 Lossless 4050 4000 4000 0 50 100 150 200 250 300 350 400 450 500 AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  24. 24. Possible Configuration C L AccLab BmSci ICR KyotoUniversity 19 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  25. 25. Possible Configuration C L AccLab BmSci ICR KyotoUniversity 19 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  26. 26. Possible Configuration C L AccLab BmSci ICR KyotoUniversity 20 The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY
  27. 27. Summary The structure can improve Q on some structure. The insulating layers should have openings for magnetic flux to go through. An insulating layer between conducting layers forms resonator and the resonance may increase the magnetic field. Need more study... AccLab BmSci ICR KyotoUniversity The 4th International WS on Thin Films and New Ideas for pushing the limits of RF Sc, 2010 Oct.4, Legnaro National Laboratories (Padua) ITALY

×