Ansoft HFSS Material Manager

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1 Choose Perfect Conductor to define a perfectly conducting material that is, a material with infinite conductivity. No field solution is performed inside a perfect conductor. Solve Inside is set to No to indicate this when you assign a perfect conductor to an object. If Perfect Conductor is selected, no functional material properties may be defined. The Options button is disabled to indicate this. Maxwell Online Help System 235 Copyright Ansoft Corporation

2 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Some materials exhibit characteristics that vary with direction and need to be specified by defining their anisotropy tensors. You must define the three diagonals for anisotropic permittivity, electric loss tangent, conductivity, permeability, and magnetic loss tangent. Each diagonal represents a tensor of your model along an axis. > To define the diagonals, follow this general procedure: 1. Select Anisotropic Material from the Material Attributes box for the material you are creating. 2. Select the property you wish to define from the following: Permittivity Elec. Loss Tan Conductivity Permeability Mag. Loss Tan 3. If any of the diagonals are functions, choose Options to specify which diagonals are constant values and which are functions. When you complete this step, any functional diagonals appear as undefined. 4. Select Functions to define your functions, then enter the name of the function in the property value field. 5. Repeat steps 3 and 4 for each of the properties. 6. Enter the name of the material in the Material Attributes box. 7. Choose Enter to accept this material. The new material now appears in the Materials list and can be assigned to objects. Maxwell Online Help System 236 Copyright Ansoft Corporation

3 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Anisotropic Permittivity The permittivity tensor for an anisotropic material is described by where ε 1 is the relative permittivity of the material along one tensor axis. ε 2 is the relative permittivity along the second axis. ε 3 is the relative permittivity along the third axis. ε 0 is the permittivity of free space. The relationship between E and D is then ε D x D y ε 1 ε ε 2 ε ε 3 ε 0 ε E x E y D z E z > To specify the relative permittivity for an anisotropic material: 1. Choose Permittivity. 2. Enter the value of ε 1 in the diag[1] field. 3. Enter the value of ε 2 in the diag[2] field. 4. Enter the value of ε 3 in the diag[3] field. If the relative permittivity is the same in all directions, use the same value for ε 1, ε 2, and ε 3. If any of these values are functions, choose Options and select which values are to be defined as functions. You define the functions by choosing Functions. Maxwell Online Help System 237 Copyright Ansoft Corporation

4 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Anisotropic Electric Loss Tangent The electric loss tangent tensor for an anisotropic material is described by: [ ε] ε' 1 ( 1 jtanδ 1 ) ε' 2 ( 1 jtanδ 2 ) ε' 3 ( 1 jtanδ 3 ) where: tanδ 1 is the ratio of the imaginary relative permittivity ( ε'' 1 ) to the real relative permittivity ( ε' 1 ) in one direction. tanδ 2 is the ratio of the imaginary relative permittivity ( ε'' 2 ) to the real relative permittivity ( ε' 2 ) in the second direction. tanδ 3 is the ratio of the imaginary relative permittivity ( ε'' 3 ) to the real relative permittivity ( ε' 3 ) in the third orthogonal direction. ε' 1, ε' 2, and ε' 3 are the real relative permittivities specified earlier. j is the imaginary unit, 1. The relationship between D and E will then be: D x D y D z [ ε] E x E y E z > To specify the electric loss tangent for an anisotropic material: 1. Choose Elec. Loss Tan. 2. Enter the value of tanδ 1 in the diag[1] field. 3. Enter the value of tanδ 2 in the diag[2] field. 4. Enter the value of tanδ 3 in the diag[3] field. If the electric loss tangent is the same in all directions, use the same value for tanδ 1, tanδ 2, and tanδ 3. If any of these values are functions, choose Options and select which values are to be defined as functions. You define the functions by choosing Functions. Maxwell Online Help System 238 Copyright Ansoft Corporation

5 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Anisotropic Conductivity The conductivity tensor for an anisotropic material is described by: [ σ] where: σ 1 is the relative conductivity along one axis of the material s conductivity tensor. σ 2 is the relative conductivity along the second axis. σ 3 is the relative conductivity along the third axis. The relationship between J and E is then: J x J y σ σ σ 3 σ E x E y J z E z > To specify the conductivity for an anisotropic material: 1. Choose Conductivity under Material Attributes. 2. Enter the value of σ 1 in the diag[1] field. 3. Enter the value of σ 2 in the diag[2] field. 4. Enter the value of σ 3 in the diag[3] field. The values of σ 1 and σ 2 apply to axes that lie in the xy cross-section being modeled. The values of σ 3 apply to the z-component. These values affect current flowing in dielectrics between the conductors. If any of these values are functions, choose Options and select which values are to be defined as functions. You define the functions by choosing Functions. Maxwell Online Help System 239 Copyright Ansoft Corporation

6 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Anisotropic Permeability The permeability tensor for an anisotropic material is described by: [ µ ] where: µ 1 is the relative permeability along one axis of the material s permeability tensor. µ 2 is the relative permeability along the second axis. µ 3 is the relative permeability along the third axis. µ 0 is the permeability of free space. The relationship between B and H is: µ 1 µ µ 2 µ µ 3 µ 0 > To specify the relative permeability for an anisotropic material, 1. Choose Permeability in the Material Attribute box. 2. Enter the value of µ 1 in the diag[1] field. 3. Enter the value of µ 2 in the diag[2] field. 4. Enter the value of µ 3 in the diag[3] field. B x B y µ B z If the relative permeability is the same in all directions, use the same value for µ 1, µ 2, and µ 3. If any of these values are functions, choose Options and select which values are to be defined as functions. You define the functions by choosing Functions. H x H y H z Maxwell Online Help System 240 Copyright Ansoft Corporation

7 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports Anisotropic Magnetic Loss Tangent The magnetic loss tangent tensor for an anisotropic material is described by: [ µ ] µ' 1 ( 1 jtanδ M1 ) µ' 2 ( 1 jtanδ M2 ) µ' 3 ( 1 jtanδ M3 ) where: tan δ M1 is the ratio of the imaginary relative permeability ( µ'' 1 ) to the real relative permeability ( µ' 1 ) in one direction. tan δ M2 is the ratio of the imaginary relative permeability ( µ'' 2 ) to the real relative permeability ( µ' 2 ) in the second direction. tan δ M3 is the ratio of the imaginary relative permeability ( µ'' 3 ) to the real relative permeability ( µ' 3 ) in the third direction. µ' 1, µ' 2, and µ' 3 are the real relative permeabilities specified earlier. j is the imaginary unit, 1. The relationship between B and H will then be: B x B y [ µ ] B z H x H y H z > To specify the magnetic loss tangent for an anisotropic material: 1. Choose Mag. Loss Tan. 2. Enter the value of tanδ M1 in the diag[1] field. 3. Enter the value of tanδ M2 in the diag[2] field. 4. Enter the value of tanδ M3 in the diag[3] field. If the magnetic loss tangent is the same in all directions, use the same value for tanδ M1, tanδ M2, and tanδ M3. If any of these values are functions, choose Options and select which values are to be defined as functions. You define the functions by choosing Functions. Maxwell Online Help System 241 Copyright Ansoft Corporation

8 Anisotropic Permittivity Anisotropic Electric Loss Tangent Anisotropic Conductivity Anisotropic Permeability Anisotropic Magnetic Loss Tangent and Ports and Ports An anisotropic material can be in contact with a port provided that there is no loss on the port, i.e., a lossy material or boundary condition (finite conductivity or impedance) cannot be in contact with the port. Although a radiation boundary is lossy, it can be in contact with a port in this case because it is generally not modeled as lossy where it touches the port. Note that a radiation boundary can be modeled as lossy if the environment variable ZERO_ORDER_ABC_ON_PORT is set. one principal axis of the anisotropic material is aligned normal to the port. Maxwell Online Help System 242 Copyright Ansoft Corporation

9 Saturation Magnetization Delta H Lande g factor Ferrite Materials and Ports In Ansoft HFSS, select B-H Nonlinear Material to define a ferrite. Use ferrite materials to model the interaction between a microwave signal and a ferrite material whose magnetic dipole moments are aligned with an applied bias field. The gyrotropic quality of the ferrite is evident in the permeability tensor which is Hermitian in the lossless case. The Hermitian tensor form leads to the non-reciprocal nature of the devices containing microwave ferrites. If the microwave signal is circularly polarized in the same direction as the precession of the magnetic dipole moments, the signal interacts strongly with the material. When the signal is polarized in the opposite direction to the precession, the interaction will be weaker. Because the interaction between the signal and material depends on the direction of the rotation, the signal propagates through a ferrite material differently in different directions. Note: Nonlinear materials are not available for Eigenmode Solution problems. > To assign a ferrite material to an object: 1. When you select Nonlinear Material, the following fields appear: Rel Permittivity Conductivity Elec Loss Tan Saturation Mag. Lande g factor Delta H 2. Enter the relative permittivity, ε r, of the material in the Rel Permittivity field. 3. Enter the conductivity, σ, of the material in the Conductivity field. 4. Enter the electric loss tangent, ε /ε, of the material in the Elec Loss Tan field. 5. Enter the saturation magnetization of the material in the Saturation Mag. field. 6. Enter a value for the Lande g factor in the Lande g factor field. 7. If the ferrite is lossy, enter the ferromagnetic resonance line width in the Delta H field. Otherwise, leave this field set to zero. Maxwell Online Help System 243 Copyright Ansoft Corporation

10 Saturation Magnetization Delta H Lande g factor Ferrite Materials and Ports Saturation Magnetization When a ferrite is placed in a uniform magnetic field, the magnetic dipole moments of the material begin to align with the field. As the strength of the applied bias field increases, more of the dipole moments align. The saturation magnetization, M s, is a property which describes the point at which all of the magnetic dipole moments of the material become aligned. At this point, further increases in the applied bias field strength do not result in further saturation. The relationship between the magnetic moment, M, and the applied bias field, H, is shown below: Enter the saturation magnetization, 4πM s, in the Saturation Mag. field. The saturation magnetization is entered in gauss. Delta H Magnetic Moment M Ms 0 Applied bias field H Delta H is the full resonance line width at half-maximum, which is measured during a ferromagnetic resonance measurement. It relates to how rapidly a precessional mode in the biased ferrite will damp out when the excitation is removed. The factor H doesn t appear in the permeability tensor; instead, the factor α appears. The factor α is computed from: γµ α 0 H ω The factor α changes the κ and χ terms in the permeability tensor from real to complex, which makes the tensor complex non-symmetric (where it had been hermitian for lossless ferrites). Enter the full resonance line width at half maximum in the Delta H field. The full resonance line width at half maximum is entered in oersteds. Maxwell Online Help System 244 Copyright Ansoft Corporation

11 Saturation Magnetization Delta H Lande g factor Ferrite Materials and Ports Lande g factor The Lande g factor is a ferrite property that, on a microscopic level, describes the total magnetic moment of the electrons according to the relative contributions of the orbital moment and the spin moment. When the total magnetic moment is due entirely to the orbital moment, g is equal to one. When the total magnetic moment is due entirely to the spin moment, g is equal to two. For most microwave ferrite materials, g has a range from 1.99 to Enter the Lande g factor in the Lande g factor field. The Lande g factor is dimensionless. Ferrite Materials and Ports When designing a problem containing ferrite materials and ports, do not arrange the port so that it touches the ferrite material. If you must place a port on a ferrite material, separate the two with a dielectric with a relative permittivity equal to the relative permittivity of the ferrite. If your problem contains a port that touches a ferrite material, the following error message appears during the solution process: Can not solve portname with ferrite material materialname on the port. Maxwell Online Help System 245 Copyright Ansoft Corporation

12 Options Functions Common Functions Defining a Function Changing a Function Deleting a Function Any material property that can be specified by entering a constant can also be specified using a mathematical function, which you can define. Functional material properties can be used to define material properties whose value is given by a mathematical relationship for instance, one relating it to frequency or another property s value. > In general, to define a functional material property: 1. Add or derive a Local material. 2. Choose Options to specify which material properties are constant and which are functional. 3. Choose Functions to define math functions that describe the material property s behavior. 4. Enter the appropriate function name as the value for the material property. Options Choose Options to identify which material properties vary as functions and which remain constant. For each material property, select one of the following: Constant. The material property s value is constant throughout an object (the default). Functional. The material property s value is a function which defines the value of the material property. Maxwell Online Help System 246 Copyright Ansoft Corporation

Options Functions Common Functions Defining a Function Changing a Function Deleting a Function Functions Choose Functions to define mathematical functions.

13 Options Functions Common Functions Defining a Function Changing a Function Deleting a Function Functions Choose Functions to define mathematical functions. The Function Definitions window appears and is identical to the Expression Evaluator accessible from the Maxwell Control Panel s Utilities panel. Maxwell Online Help System 247 Copyright Ansoft Corporation

14 Options Functions Common Functions Defining a Function Changing a Function Deleting a Function Common Functions The following functions may be used to define mathematical expressions: Basic Functions Intrinsic functions Trigonometric expressions /, +, -, *, % (modulus), ** (exponentiation), - (Unary minus), << (left shift), >> right shift, (equals),! (not equals), > (greater than), < (less than), > (greater than equals), < (less than equals), & (bitwise and), (bitwise or), ^ (bitwise xor), ~ (1 s compliment), && (logical and), II (logical or),! (factorial) if, sign (returns the sign of an argument), abs, exp, pow, ln (natural log), log (log to the base 10), lg (log to the base 2), sqrt, floor, ceil, round, rand (returns a random number between 0 and 1), deg, rad sin, cos, tan, asin, acos, atan, sinh, cosh, tanh All trigonometric expressions expect their arguments to be in degrees, and the inverse trigonometric functions return values are in degrees. These function names are reserved and may not be used as variable names. Maxwell Online Help System 248 Copyright Ansoft Corporation

15 Options Functions Common Functions Defining a Function Changing a Function Deleting a Function Defining a Function > In general, to define a function: 1. Enter the function name in the field to the left of the equals sign. Function names must start with an alphabetic character, and may include alphanumeric characters and the underscore. Note that pi is a built-in constant and may not be redefined. 2. Enter the expression for the function in the field to the right of the equals sign. Note: The predefined variables X, Y, Z, PHI, THETA, and R must be entered in capital letters. X, Y, and Z are the rectangular coordinates. PHI, THETA, and R are the spherical coordinates. 3. Choose Add or press Return. The function is then listed in the following fields: Name Value Expression 4. When you finish adding functions, choose Done. Changing a Function > To modify an existing function: 1. Select the function. 2. Change any variables, operators, intrinsic functions, or other factors. 3. Choose Update. The updated function appears. Deleting a Function > To delete a function: 1. Select the function you wish to delete. 2. Choose Delete. The selected function is deleted. Displays the name of the function. Displays the numeric value of the function (if applicable). Displays the function. Maxwell Online Help System 249 Copyright Ansoft Corporation

Ansoft HFSS 3D Boundary Manager Sources

Ansoft HFSS 3D Boundary Manager Sources Lumped Gap Defining s Voltage and Current When you select Source, you may choose from the following source types: Incident wave Voltage drop Current Magnetic bias These sources are available only for driven