Model Gallery

The Model Gallery features COMSOL Multiphysics model files from a wide variety of application areas including the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use models and step-by-step instructions for building the model, and use these as a starting point for your own modeling work. Use the Quick Search to find models relevant to your area of expertise, and login or create a COMSOL Access account that is associated with a valid COMSOL license to download the model files.

Lossy Circular Waveguide

In mode analysis it is usually the primary goal to find a propagation constant. This quantity is often, but not always, real valued; if the analysis involves some lossy part, such as a nonzero conductivity or an open boundary, the eigenvalue is complex. In such situations, the real and imaginary parts have separate interpretations: The real part is the propagation constant The imaginary part is ...

H-bend Waveguide 2D and 3D

These examples show how to model a rectangular waveguide for microwaves in 2D and 3D. A single hollow waveguide can conduct two kinds of electromagnetic waves: transversal magnetic (TM) or transversal electric (TE) waves. The models examine a TE wave that has no electric field component in the direction of propagation. More specifically, for the models, you select the frequency and waveguide ...

Tunable Evanescent Mode Cavity Filter using a Piezoelectric Device

An evanescent mode cavity filter can be realized by adding a structure inside of the cavity. This structure changes the resonant frequency lower than the dominant mode of the unfilled cavity. A piezo actuator is used to control the size of a small air gap which provides the tunability of the resonant frequency.

Dielectric Resonator Antenna (DRA) with Parasitic Array

A dielectric resonator placed near a radiating element can be used to increase directivity and gain. Here, a block of quartz dielectric, with additional passive metallic antenna elements, is placed above a slot antenna. The fields in and around the antenna are solved for. The far field pattern and impedance is computed and improved performance is seen.

Wilkinson Power Divider

Some conventional three-port power dividers are resistive power dividers and T-junction power dividers. Such dividers are either lossy or not matched to the system reference impedance at all ports. In addition, isolation between two coupled ports is not guaranteed. The Wilkinson power divider outperforms the lossless T-junction divider and the resistive divider and does not have the issues ...

Radome with Double-layered Dielectric Lens

A radome minimizes losses and improves radiation characteristics of an antenna through its design. The structure can be optimized to minimize the transmission loss and also designed to improve radiation characteristics including antenna directivity and side lobes. Shown in the model is the surface current density on the patch antenna, the magnitude of the electric potential on the antenna's ...

Transient Modeling of a Coaxial Cable

Simulation of Maxwell’s equations in the time domain is useful if the objective of the analysis is to observe a transient phenomenon, to find the time it takes a signal to propagate, or if the materials being modeled are non-linear with respect to the electric or magnetic field strength. This model simulates a pulse propagating down a coaxial transmission line and observes the time it takes for ...

Finding the Impedance of a Parallel-Wire Transmission Line

A parallel wire transmission line is composed of two conducting wires in a dielectric such as air. The fields around such a transmission line are not directly confined by the conductors, and extend to infinity, although they drop off in rapidly away from the wires. This model demonstrates how to compute the fields and impedance of such an unshielded transmission line, and compares to the analytic ...

Defining a Mapped Dielectric Distribution of a Metamaterial Lens

This example demonstrates how to set up a spatially varying dielectric distribution, such as might be engineered with a metamaterial. Here, a convex lens shape is defined via a known deformation of a rectangular domain. The dielectric distribution is defined on the undeformed, original rectangular domain and is mapped onto the deformed shape of the lens. Although the lens shape defined here is ...

Connecting a 3D Electromagnetic Waves Model to an Electric 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.

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