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.

Dipole Antenna with a Quarterwave Coaxial Balun (1:1)

An antenna balun blocks undesirable currents on the outside of a cable. A quarter-wave coaxial balun (1:1) is one of the easiest designs: it works as a transformer and makes the input impedance from the inner conductor to the outer conductor infinite. This model simulates an antenna prototype including a SMA Receptacle, an ABS enclosure and a quarter-wave coaxial balun. The frequency is tuned to ...

Antenna Decoupling Using Electromagnetic Band Gap (EBG) Metamaterial

An Electromagnetic Band Gap (EBG) structure can be used to increase the isolation between antennas close to each other. The decoupling effect is not only a function of frequency but also polarization and coupling-plane configuration. When designing an EBG structure, one needs to make sure to not apply an incorrect frequency and polarization, since this would increase the coupling between ...

Branch Line Coupler

A Branch Line Coupler (Quadrature 90° Hybrid) is a four-port network device with a 90° phase difference between two coupled ports. The device can be used for a single antenna Transmitter/Receiver system or an I/Q signal splitter/combiner. The objective of this model is to compute the S-parameters and to observe the matching, isolation, and coupling around the operating frequency.

Vivaldi, Tapered Slot Antenna (TSA)

A tapered slot antenna, also known as a Vivaldi antenna, is useful for wide band applications. Here, an exponential function is used for the taper profile. The objective of this model is to compute the far-field pattern and to compute the impedance of the structure. Good matching is observed over a wide frequency band.

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 Slab Waveguide

A planar dielectric slab waveguide demonstrates the principles behind any kind of dielectric waveguide such as a ridge waveguide or a step index fiber. This model solves for the effective index of a dielectric slab waveguide, as well as the fields, and compares to analytic results.

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.

Optimizing a Bowtie Antenna

A bowtie antenna patterned on a dielectric substrate is optimized by changing the length of the arms and the flare angle to reduce the magnitude of S11, the reflection coefficient. The two geometric dimensions that are used as design variables directly control the size and shape of the antenna, and also affect the dimensions of the dielectric substrate. The gradient-free Nelder-Mead optimization ...

Three-Port Ferrite Circulator

A microwave circulator is a multiport device in which a wave incident on Port 1 is coupled only into Port 2; a wave incident on Port 2 is coupled only into Port 3; and so on. Circulators are used to isolate microwave components, for example, to couple a transmitter and a receiver to a common antenna. They typically rely on anisotropic materials, most commonly ferrites. This model simulates the ...

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 ...

Quick Search