New designing tools for the modeling of non-saturated ferrite : application to twin toroids phase shifters

Transcription

1 New designing tools for the modeling of non-saturated ferrite : application to twin toroids phase shifters EUC 2016 legouellec@univ-brest.fr Armel Le Gouellec 1, G. Verissimo 1, V. Laur 1, P. Queffelec 1, I. Albert 2 1 University of Brest, France 2 Centre National d Etudes Spatiales, Toulouse, France

2 Introduction / Context Phased array antennas Phased array antennas for spatial applications Emission use : High power devices ( around 50 W on each phase shifter) 2

3 Introduction : polycrystalline ferrite Permeability tensor as a function of : External DC magnetic field Temperature Mechanical stress Anisotropic and dispersive materials 3

4 Introduction : polycrystalline ferrite Grains, domains and walls H 0 =0 weak H 0 wall bulge φ reversible strong H 0 wall bulge and shift φ non-reversible Intense H 0 Wall disappearance Very intense H 0 Momentum rotation toward the applied field direction Ferrite material divided as grains Weiss domain Bolch walls M Applied H0 Grains divided as domains First magnetization curve Domains divided as magnetic momentum H 4

5 Introduction Magnetization process Working state C Max ΔΦs1 Current impulsions (A) 0 C Min S1 X 10 Temps 5

6 Introduction Issues E.M. simulation software can t describe remanent states of magnetization phase-shift predicted Cut and try design time- and money-consuming 6

7 Needs Introduction Find a predictive permeability tensor ( µ ) model working in any magnetization state Circulators Self biased circulators & isolators Phase shifters Tunable filters Miniaturized antennas Magnetostatic study Material model 3D EM study 7

8 Existing permeability tensor models Initial permeability (demagnetized): Schlömann s model µ 0 = + µ κ 3 3 Losses badly described!! Green & Sandy (empirical) Non saturated media : Low H 0 ' ' M 3/ 2 µ ' = µ 0 + (1 µ 0)( ) Rado s model M s (statistical) ' µ z = µ ' 1 ( 0 M M s 5 / 2 ) Saturated media: high H 0 Polder tensor µ * jκ*0 µ p= jκ* µ * * ω ω + αω µ = + m( o j ) 1 2 ( ω o+ jαω) ω * ω ω κ = m 2 2 ( ω o+ jαω) ω 2 ωm κ = * ω ωm=γm ω o= γho M M s Non-predictive (uses of M/M s ) s 8

9 Existing permeability tensor models GPT (Generalized Permeability Tensor) Quantification of the Polder-Smit effect (broadening of the absorption peak at low-field) Magnetization law (Stoner & Wolfhart) interactions between grains 1 2 Statistical distribution over all the direction of the easy axis θi, over the domain shapes and over the grain shapes interactions between adjacent domains µ valid magnetization state in one computation P. Gelin, P. Quéffélec, and F. Le Pennec, Effect of domain and grain shapes on the dynamic behavior of polycristalline ferrites..., J. App. Phys., vol. 98, , Sept. 1st,

10 Magnetostatic study Magnetostatic study Material model Full permeability tensor 3D EM study Magnetostatic study: Commercial software solution (Ex : Ansys Maxwell-3D) A single B(H) curve to describe the whole ferrite Can describe saturated ferrite or ferrite on the first magnetization curve Can not describe ferrite in other magnetization state ( partially magnetized or remanent ) «Homemade» magnetostatic solver G. Verissimo ( Lab-STICC, UBO ) A full hysteresis cycle (Stoner and Wohlfarth) in each mesh cell Each mesh cell can follow a different hysteresis cycle (minor or major) Can describe any magnetization state 10

11 Magnetostatic study Homemade Magnetostatic study Magnetization In each mesh cell Material model Polder model Full permeability tensor per mesh cell 3D EM study Only valid for saturated ferrite Ansys HFSS Diagonal tensor Polder model Extra diagonal elements useful in order to describe the phase shift Only valid for saturated ferrite CST Microwave Studio Macro Can create a full tensor frequency dependent material 11

12 Macros in CST Scripts in Virtual Basic (VBA) language Allows task automation such as material or 3D objet creation When creating a material the function «tensor formula» allows the users to creation a material described by a 9 elements tensor Each tensor element can be complex and frequency dependent CST frequency solver needs to able to compute the permeability whatever the frequency is -> interpolation needed 12

13 Interpolation μ = μ 0 μ μ μ μ μ μ μ μ μ FFF = bb 0 + bb 1 ff + + bb 6 ff aa 1 ff + + aa 4 ff 4 Interpolation function Points file from GPT Full tensor material macro Frequency dependent functions 13

14 A new design methodology Magnetostatic study Number of blocs Zone magnetization Zone dimensions GPT Model 9 complex elements tensor per bloc Interpolation routine Number of blocs Zone dimensions Flag File Macro CST Tensors elements as frequency dependent function 14

15 Macros in CST 3D design of the phase shifter in CST 1 bloc in CST per magnetostatic mesh cell Bloc dimensions Xmin, Xmax,, Zmin, Zmax Xmin, Xmax,, Zmin, Zmax Tensor elements ( Complex and f dependent) μ 11, μ 12,, μ 32, μ 33 Bloc 1 Bloc 2 Bloc 1 Ferrite Air Flag Exemple : Zone 1 Bloc 1 creation 1 0 Full tensor material or air? Bloc 1 Bloc 2 μ 11, μ 12,, μ 32, μ 33 Bloc 2 Full tensor material definition Zone 1 created 15

16 First test : saturated ferrite Ferrite slab Z X-band waveguide (WR-90) Applied DC field: H app =4000 Oe (electromagnet) X Y 16

17 First test : saturated ferrite N N = N N H = N N N H ext N N N NM Demagnetizing field non-uniform in the ferrite sample Internal magnetic fields are space dependent Creation of 9 blocks in CST to model this non-uniformity ( In witch the internal fields are taken as uniform in module and direction) 17

18 First test : saturated ferrite ω 2 Simulation method Polder : - HFSS - CST Gap between simulation and measure (main peak) 870 MHz (7,3%) 920 MHz (8,6%) Gap between simulation and measure (secondary peak ω 2 ) GPT uniform 270 MHz (2,4%) GPT non-uniform 120 MHz (1,1%) 160 MHz (1,5%) 18

19 3D desing in CST Application to twin toroid phase shifters Under CST : creation of one block for each magnetostatic mesh cell 19

20 Application to twin toroid phase shifters Simulation VS Measures Measure Simulation - Simulated max phase shift close from the one measured - Applied current use to start a phase shift close from the one measured 20

21 Application to twin toroid phase shifters Simulation VS Measures Good agreement on the reflection coefficient Weaker insertion losses than measured 21

22 Objective: Conclusion Creation of new sets of tools in order to design twin toroid phase shifters A new methodology : Magnetostatic study Number of blocs Zone magnetization Zone dimensions GPT Model 9 complex elements tensor per bloc Interpolation routine Number of blocs Zone dimensions Flag File Macro CST Tensors elements as frequency dependant function 22

23 Prospects Application of these tools to other ferrites devices : Phase shifter in other frequencies Circulators, Tunable Filters, etc. etc. Use of the developed macros for other dispersive materials Plasmas, Ferroelectrics, etc. 23