RF Module Updates


For users of the RF Module, COMSOL Multiphysics® version 6.3 introduces an interface for computing RLGC parameters for multiconductor transmission lines. Additionally, a new logarithmic default plot offers intuitive visualization, while several example models have been extended to include uncertainty quantification analysis, showcasing how to account for robustness and reliability of RF analyses. Learn more about these updates below.

New Predefined Multiphysics Interface for Transmission Line Parameter Analysis

The new Transmission Line, RLGC Parameters interface is used to compute multiconductor transmission line parameters, including series resistance, inductance, shunt conductance, and capacitance per unit length, as well as the characteristic impedance and propagation constant. This interface combines the Electric Currents and Magnetic Fields interfaces for frequency-domain modeling, supporting 2D analysis of transmission line cross sections. The new Transmission Line Parameters of a Coaxial Cable tutorial model showcases this interface.

The COMSOL Multiphysics UI showing the Model Builder with the Global Evaluation node highlighted, the corresponding Settings window, and a coaxial cable model in the Graphics window.
Surface plot of the electric potential and streamline plot of the electric field of a coaxial cable.

New Default Plot for More Intuitive Visualization

A new default plot, Electric Field, Logarithmic, has been added to the Electromagnetic Waves, Frequency Domain interface. This plot is based on the characteristics of physics features and selections in the model and uses a logarithmic scale to provide more intuitive visualization of field intensity decay. It also emphasizes conductive surfaces via perspective that enhances 3D perception. All 3D tutorial models computed with an Electromagnetic Waves, Frequency Domain interface and Frequency Domain study have been updated to showcase this new plot.

The new default plots of a branchline coupler tutorial model and a Wilkinson power divider tutorial model.

Uncertainty Quantification of Microwave Components

The RF Module Application Library has been extended to introduce uncertainty quantification for microwave devices, examining how variations in input parameters, such as material properties or geometric variations, affect the device's performance in terms of the S-parameter. The analysis includes a screening study to identify which parameters most significantly influence key performance metrics. It also evaluates the relative effects of these parameters and their interactions in sensitivity analysis. Reliability analysis assesses the robustness of the final design with respect to variations in design parameters by determining the probability of achieving the specified performance criteria. The Bow-Tie Antenna Optimization and Uncertainty Quantification Study for a Microstrip Patch Antenna tutorial models showcase this new functionality.

The COMSOL Multiphysics UI showing the Model Builder with the Uncertainty Quantification node highlighted, the corresponding Settings window, and four Graphics windows.
An uncertainty quantification analysis performed on a microstrip patch antenna.

Matched Boundary Condition Added to the Electromagnetic Waves, Frequency Domain Interface

The Matched Boundary Condition feature has been added to the Electromagnetic Waves, Frequency Domain interface, making boundaries transparent to waves with a known scattered direction, minimizing reflections. For scenarios with an incident field, a Reference Point subnode can be used to define the phase of the incident wave.

New and Updated Tutorial Models

COMSOL Multiphysics® version 6.3 brings several new tutorial models to the RF Module.