6. Electromagnetics Enhancements

Training Manual Aug Electromagnetics Enhancements Emag focus in ANSYS 5.7 is on high-frequency electromagnetics (discussed next). Other Emag enhancements: –LMATRIX (inductance calculation) improvements Output array contains the NxN inductance matrix (as before) and a new N+1 th column containing flux linkage values, with the I th row corresponding to the I th coil. –SENERGY (magnetic energy calculation) is more robust, accurate, and faster.

Training Manual Aug … Electromagnetics Enhancements Other Emag enhancements (cont'd): –New diode element, CIRCU125 To simulate a common or Zener diode. Can interface with circuit element CIRCU124, transducer element TRANS126, and mechanical elements MASS21, COMBIN14, and COMBIN39 for coupled-field analyses. Can be defined using the circuit builder. CIRCU125

Training Manual Aug High Frequency Electromagnetics Overview In ANSYS, HF Electromagnetics is used to simulate the full wave electromagnetic phenomena. –RF/microwave problems (interior wave propagation) –Radiation and scattering problems (exterior wave propagation) Available in ANSYS/Multiphysics and ANSYS/Emag HF products. HF solution is in the frequency domain. No limit on the highest frequency allowed.

Training Manual Aug … High Frequency Electromagnetics Overview (cont'd) Major components of a HF FEA model HF Postprocessing Excitations materials Boundary conditions Modal analysis Harmonic analysis CAD import New/enhanced Existing HF Elements

Training Manual Aug … High Frequency Electromagnetics Overview (cont'd) ANSYS 5.7 takes a major leap in HF simulation capabilities with several new features and enhancements: –New boundary conditions PML (perfectly matched layer), impedance –New excitations Waveguide ports; plane wave; surface magnetic field, surface electric field, and current density excitations –Elements New HF118 element, enhancements to HF119 & HF120 –Solvers and postprocessing

Training Manual Aug HF Electromagnetics - New BC's PML Perfectly Matched Layer (PML) Absorbing layers of elements used for the truncation of the HF FEA domain. Reduce the FEA domain significantly by replacing the outer computation domain (infinite) with an absorbing layers. Required in many real world applications: –Exterior phenomena, e.g, antenna and EMC/EMI problems. –Interior phenomena, e.g, waveguides and transmission lines.

Training Manual Aug HF Electromagnetics - New BC's … PML PML region is simply a layer (or layers) of elements placed at the boundary of the field domain. Elements used are 119 and 120 with KEYOPT(4) = 1. For example: ET,2,HF120,,,,1 –Extend the material properties in the field region into PML –PML supports symmetry boundary conditions PML Surrounding field HF Device Schematic of cross section of a 3D PML region

Training Manual Aug HF Electromagnetics - New BC's … PML Recommendations: –PML boundary edges should be parallel to global Cartesian or Cartesian ESYS. –Thickness of PML region > 0.25*wavelength. –Allow at least 4-5 layers of elements in surrounding field as buffer zone between device and PML. –Four elements through the thickness of PML region for - 50 Db attenuation. More attenuation can be obtained by adding more PML layers. PML1 PML2 PML3 ESYS1 ESYS2 ESYS3 Schematic of 1D PML layers PML1 PML2 PML3 ESYS1 ESYS2

Training Manual Aug HF Electromagnetics - New BC's Impedance Four types of impedance BC's are now available: –Far-field radiation boundary –Air-dielectric boundary –PEC (perfect electric conductor) surface with dielectric coating –Non-PEC surface Apply using SF family of commands dielectric air-dielectric Interface air far-field boundary PEC with dielectric coating non-perfect conductor surface of non-perfect conductor

Training Manual Aug HF Electromagnetics - New Excitations Waveguide Ports New parallel-plate waveguide –Can be used to simulate problems like micro-strip. All four types of waveguides –Z axis can be in either the wave propagation direction or the opposite direction. X-axis must be parallel to width of port. –Origin for rectangular waveguide is at center, different from 5.6. x y z Rectangular Waveguide Parallel-Plate Waveguide Circular Waveguide Coax Waveguide new x y x y x y z x y z

Training Manual Aug HF Electromagnetics - New Excitations...Waveguide Ports Higher-order modes are now available at 5.7:

Training Manual Aug HF Electromagnetics - New Excitations...Waveguide Ports HFPORT,Portnum,Porttype,Local,Mode,Portbc, VAL1,VAL2,VAL3,VAL4,VAL5 New HFPORT command replaces PORTOPT. Port boundary conditions by Portbc in HFPORT: –IMPDMatching the impedance of the single mode. –SEXTTerminating the port w/ PML layers. An invisible port to extract S-parameters. –SOFTEquivalent current excitation. Allow multiple ports & multiple modes. Can extract S-parameter. –HARDFixed electromagnetic field at port.

Training Manual Aug HF Electromagnetics - New Excitations...Waveguide Ports Schematics of four Portbc options for waveguides in HFPORT command port SEXT port IMPD HARD incident wave reflection wave SOFT incident wave PML2 PML1

Training Manual Aug HF Electromagnetics - New Excitations Plane Wave New PLWAVE command replaces PLANEWAVE: –PLWAVE, EX, EY, EZ, AngX, AngZ EX, EY and EZ are the electric field amplitudes in X, Y and Z directions. AngX and AngZ are the angles of the wave to X-axis and Z- axis. –Used for scattering analysis in EMC/EMI analysis

Training Manual Aug HF Electromagnetics - New Excitations Source Terms You can now specify the following excitation sources (using the BF family of commands): –Magnetic field (H) at a surface. –Electric field (EF) at a surface. –Current density (JS) at a point, line, surface, or volume.

Training Manual Aug HF Electromagnetics Element Enhancements New 2.5-D, 8-node HF118 element –Extract eigenvalues of guided wave structures (waveguides or transmission lines). –Applicable for modal analyses (Block Lanczos). –Quadrilateral or triangular shapes. –Both 1st order and 2nd order available. –To calculate cutoff frequencies and propagating constants used together with HFEIGOPT.

Training Manual Aug HF Electromagnetics … Element Enhancements HF119 (10-node tet) gets new 2nd-order option –Applicable to both modal and full harmonic analyses –Keyopt(1) = 2 –Better accuracy compared with 1st order element, especially for complex geometry HF120 (20-node brick) gets improved 2nd-order option –DOFs from 36/element to 54/element –Complete vector basis functions –Better accuracy for higher-order modes

Training Manual Aug HF Electromagnetics Solution and Postprocessing Sparse solver is now the default (not frontal). –ICCG and FRONTAL also available as before Choosing analysis types –Harmonic analysis (Antype, harmic) HFSCAT,SCAT must be specified for RCS calculation –Modal analysis (Antype,modal) 3D or 2D modal analysis

Training Manual Aug HF Electromagnetics … Solution and Postprocessing New commands to review far-field results: –PLHFFAR to display the electromagnetic far field, radar cross-section (RCS), and antenna pattern (PATT) –PRHFFAR for listings RCS of a metal plate with incident plane wave

Training Manual Aug HF Electromagnetics … Solution and Postprocessing New HFNEAR command to calculate near-field results (EF & H). –Options to calculate at a specified point or along a path. New PRHFFAR calculates/prints far field beyond FEA domain. Other: –HFSYM to set symmetry planes for postprocessing calculations in near and far field –Current density can be shown graphically –Calculated parameters: SPARM: magnitude and phase angle of S-parameter (both single and multiple ports)