Solution Types in HFSS

Solution Types

HFSS

This enables the Driven Options Modal and Terminal.

HFSS selection enables Mesh Fusion for FEM components. You can add padding to the mesh bounding volume. The finite array is disabled, and the Hybrid folder is removed from the project tree. The FEBI boundary becomes a regular boundary instead of hybrid region. When there are components set up for mesh fusion, the solution setup only allows direct solver and no derivatives.

HFSS with Hybrid and Arrays

This enables the Driven Options Modal and Terminal.

HFSS with Hybrid and Arrays selection enables mesh assembly for hybrid components. You cannot add padding to the mesh assembly bounding volume. The finite array is enabled, and the Hybrid folder is added to the project tree, along with the tab for Hybrid in the solution setup.

HFSS Transient Transient - For calculating problems in the time domain. It employs a time-domain ("transient") solver. For Transient your choice of Composite Excitation or Network Analysis affects the options for the setup. If you select Network Analysis the setup includes an Input Signal tab for the simulation.

Typical transient applications include, but are not limited to:

  • Simulations with pulsed excitations, such as ultra-wideband antennas, lightning strikes, electro-static discharge;
  • field visualization employing short-duration excitations;
  • time-domain reflectometry.
HFSS SBR+

This option simplifies design creation for SBR+ users. HFSS can use EMA3D shooting and bouncing ray (SBR) technology to calculate the far field from current sources and defined geometry via a one-way coupling. With this solution type, you do not need to specify explicit SBR+ Hybrid Regions. The Driven option for this solutions is Network Analysis only, with no Auto-Open Region. For details, see Design Flow for SBR+ Solution Type. You can also use parametric antennas in SBR+ solutions. For SBR+ solutions, you see an option in Initial Mesh Settings to Allow tolerant meshing in SBR+ regions.

For HFSS SBR+solutions, you can also choose to import STL files as Lightweight Geometry.

HFSS Eigenmode For calculating the eigenmodes, or resonances, of a structure. The Eigenmode solver finds the resonant frequencies of the structure and the fields at those resonant frequencies. Eigenmode designs cannot contain design parameters that depend on frequency, for example a frequency-dependent impedance boundary condition.
HFSS Characteristic Mode

This option is used for calculating the characteristic modes of a structure. The structure can be metal or dielectric. The solution reports the Number of Modes, the characteristic angle and current (amp/meter), the modal significance and quality factor, and the voltage per port based in edit sources weighting. The Selecting Characteristic Modes changes the Solution Setup criteria and dialog.

You specify the minimum modal significance (default 0.02). Convergence is based on Max E rather than Max S (default (0.02).

Only discrete sweeps are supported. Only the CMA solver is supported. Only lossless boundaries are allowed. Finite conductivity boundaries are allowed but are converted to lossless. The half-space boundary is not allowed.

 

Driven Modal

Choose the Driven Modal option for HFSS Driven when you want HFSS to calculate the modal-based S-parameters of passive, high-frequency structures such as microstrips, waveguides, and transmission lines. The S-matrix solutions will be expressed in terms of the incident and reflected powers of waveguide modes. Network Analysis is the default and functions as before.

Composite Excitation provides a method for solving fields in a large frequency domain problem.

Driven Terminal

Choose the Driven Terminal option for HFSS Driven when you want HFSS to calculate the terminal-based S-parameters of single and multi-conductor transmission line ports. The S-matrix solutions will be expressed in terms of voltages and currents on the terminals. Network Analysis is the default and functions as before.

Composite Excitation provides a method for solving fields in a large frequency domain problem.

  • Auto-Open Region
  • For open region problems (typically antennas), you can choose Auto-Open Region. The option is available for HFSS Driven modal, terminal and transient solutions. This automatically creates an open region and a predefined Analysis setup for the project. You can select whether the region is Radiation, FE-BI, or PML. This simplifies the design process. If you do not choose Auto-Open Region, you must create an airbox and then assign a radiation boundary, either manually, or using the Create Open Region command. For more information on this Solution setting, see Using Auto-Open Region for the Solution Type for Antenna Designs.