Example2 Circulator

General

A 3-port circulator consisting of a Y-shape waveguide and a ferrite cylinder is analyzed.
The device’s S-parameters are solved.
Unless specified in the list below, the default conditions will be applied.
[How to Reduce the Calculation Time]

Item	Settings
Solver	Electromagnetic Analysis [Hertz]
Analysis Type	Harmonic analysis
Options	Select “Ignore the influence of face/edge electrode thickness” * Field Data to Save: Don’t save

* This is the default setting. There are no face electrodes with this model. Therefore it is irrelevant to select it or not.

The harmonic analysis is set up as follows.

Tabs	Setting Item	Settings
Mesh Tab	Element type	2nd-order element
	Multigrid/Adaptive Mesh Method	Select [Use the adaptive mesh method].
	Frequency-Dependent Meshing	Reference frequency: 10×10^9[Hz] Select “The conductor bodies thicker than the skin depth constitute the boundary condition.” No conductive bodies are used in this session. However the setting above is required.
Harmonic analysis	Frequency	Minimum: 0.8×10^10[Hz] Maximum: 1.2×10^10[Hz]
	Sweep Type	Select Linear step by division number. Division number: 20
	Input	1.0[W}

The Y-shape waveguide is created by copying a solid body and uniting them with boolean operation.

The I/O Port boundary condition is set on their I/O faces.

The walls of the waveguide are defined as electric wall in the external boundary condition.

The mesh size of the ferrite cylinder is set to 1.

* Available from the Material DB

The static magnetic field applied on the ferrite (Ferrite) is set up in the body attribute.

Body Attribute Name	Tab	Material Name
Ferrite	Static Magnetic Field	1.00×10^4[A/m]

The material properties of Ferrite are set up as follows:

Material Name	Tab	Properties
Ferrite	Permittivity	Relative permittivity: 1.1×10^1
	Permeability	Select “Use the tensor permeability”.
	Magnet	Magnetization Strength: 1.3×10^-1 Properties of Ferrite: ⊿H: 7.958×10^3 [A/m] g coefficient: 2.0×10^0

Note) The following values are used for the magnet. Saturation magnetic flux density: 1300[Gauss], Magnetic resonance FWHM: 100[Oe],

Relative permittivity: 11, tanD: 0.0015. 1300[Gauss] = 0.13[T], 100[Oe] = 7958[A/m]

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
PORT1/Face	Electric	I/O Port	Reference Impedance: Select “Use the characteristic impedance calculated from the port structure” Number of Modes Number of precalculated modes: 5 Number of modes used in the actual analysis: 1 Select modes: none
PORT2/Face	Electric	I/O Port	Same as PORT1
PORT3/Face	Electric	I/O Port	Same as PORT1
Outer Boundary Condition	Electric	Electric wall

The outer boundary of Air:

The outer boundary of Air is set as the electric wall, which is the perfect conductor.

Shown below is the I/O characteristics (S-parameters) between PORT1 and PORT2.

The isolation is exhibited around 10GHz.