The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics® software and available from the File menu.

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Finding the Impedance of a Coaxial Cable

The coaxial cable (coax) is one of the most ubiquitous transmission line structures. It is composed of a central circular conductor, surrounded by an annular dielectric, and shielded by an outer conductor. This model computes the electric and magnetic field distribution inside of the coaxial cable, analyzes the impedance, and compares the result with the analytic solution.

Computing the Radar Cross Section of a Perfectly Conducting Sphere

A classic benchmark problem in computational electromagnetics is to solve for the radar cross section (RCS) of a sphere in free space illuminated by a plane wave. This model solves for the RCS of a metallic sphere that has a very high conductivity, which can be treated as a material with infinite conductivity. Results are compare to the analytic solution, and agreement is shown.

Modeling of a UHF RFID Tag

UHF RFID tags are widely used for identifying and tracking animals. This model simulates a passive radio-frequency identification (RFID) tag for the UHF frequency range. With respect to the chip transponder’s complex impedance, a reflection coefficient is computed. This is done using an approach that differs from the conventional scattering parameter analysis method by a real reference impedance ...

Frequency Selective Surface Simulator

Frequency selective surfaces (FSS) are periodic structures that generate a bandpass or a bandstop frequency response. They are used to filter or block RF; microwave; or, in fact, any electromagnetic wave frequency. For example, you see these selective surfaces on the doors of microwave ovens, which allow you to view the food being heated without being heated yourself in the process. The ...

Substrate Integrated Waveguide

A waveguide-type structure can be fabricated on a substrate by adding vias between the microstrip line and the ground plane. Such a device will behave as a high-pass filter and is attractive because it is easy to fabricate. A model is set up that shows the S-parameters as a function of frequency. A sharp cutoff is shown at the expected frequency.

A SMA Connector on a Grounded Coplanar Waveguide

SMA connectors are popularly used on printed circuit boards (PCB) for testing. This model shows how to excite an SMA connector on a microwave substrate and how to terminate a grounded coplanar waveguide (GCPW) with 50 ohm using a lumped port and an air-bridge.

Connecting a 3D Electromagnetic Wave Model to an Electrical Circuit

A model built with the RF Module can be connected to an electrical circuit equivalent, if there is some structure outside of the model space that you wish to approximate as a circuit equivalent. In this model, the 3D model of a coaxial cable is connected to a voltage source, in series with a matched impedance, and sees a load, also of matched impedance.

Coupled-Line Bandpass Filter

It is possible to realize a narrowband bandpass filter using cascaded microstrip coupled lines. In this example, a design composed of cascaded microstrip lines, each approximately a half wave length in size at the resonant frequency, is analyzed. The model is solved for the S-parameters and a very narrow bandwidth is observed.

Waveguide Adapter

This is a model of an adapter for microwave propagation in the transition between a rectangular and an elliptical waveguide. Such waveguide adapters are designed to keep energy losses due to reflections at a minimum for the operating frequencies. To investigate the characteristics of the adapter, the simulation includes a wave traveling from a rectangular waveguide through the adapter and into ...

Detecting Orientation of a Metallic Cylinder Embedded in a Dielectric Shell

A metallic cylindrical rod is hidden inside a spherical dielectric shell and its orientation is unknown. By studying the polarization-dependent scattered field of a cylindrical object and performing a parametric sweep as a function of polarization angle, the rod is detected for the polarization angle where the scattered field is highest. The model uses a linearly polarized plane wave for the ...