# Application Gallery

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.

RF Modulex

### Evanescent Mode Cylindrical Cavity Filter

An evanescent-mode cavity filter is resonant at a frequency lower than its original fundamental mode frequency. Evanescent mode resonance can be realized by creating a discontinuity or reactance inside the cavity. The basic model was modified by the addition of a metal box at either ... Read More

### Designing a Waveguide Diplexer for the 5G Mobile Network

A diplexer is a device that combines or splits signals into two different frequency bands, widely used in mobile communication systems. This model simulates splitting properties using a simplified 2D geometry. The computed S-parameters and electric fields at the lower and upper bands ... Read More

### Sierpinski Fractal Monopole Antenna

A fractal is a mathematical form showing self-repeating patterns. By virtue of its geometrical properties, a fractal structure can generate multiple resonances in RF applications. This antenna model uses a 3rd order Sierpinski triangle and the calculated S-parameters shows good input ... Read More

### Modeling a Biconical Antenna for EMI/EMC Testing

Biconical antennas are popular for very high frequency (VHF) measurement because they support a wide frequency range. They are also useful for electromagnetic compatibility (EMC) testing where the antenna can be used as an RF source in susceptibility or immunity test. This model ... Read More

### Thermal Drift in a Microwave Cavity Filter

Microwave filters are used to eliminate unwanted frequency components in the output from microwave transmitters. They are typically inserted between a power amplifier and an antenna. The amplifiers are nonlinear and produce harmonics that must be eliminated with filters that have a ... Read More

### Microwave Filter on PCB with Stress (ODB++, ECAD Import)

Microstrip filters can be fabricated directly on a printed circuit board (PCB) with a microstrip line going from the input to the output. Along the microstrip line there are a number of stubs of certain lengths and widths. The design of the filter involves choosing the impedance of the ... Read More

### Quarter-Wave Transformer

Transmission lines are used when the frequency of the electromagnetic signals is so high that the wave nature of the signals must be taken into account. A consequence of the wave nature is that the signals are reflected if there are abrupt changes of the characteristic impedance along ... Read More

### Simulating a Corrugated Waveguide and Its Impedance

This example exemplifies how to model the impedance of a waveguide of varying cross sectional area. A more detailed description of the phenomenon and the modeling process can be seen in the blog post "[Computing the Impedance of a Corrugated Waveguide](https://www.comsol.com/blogs/computing-impedance-corrugated-waveguide/) ... Read More

### Filter Characterized by Imported S-Parameters via a Touchstone File

A Touchstone file describes the frequency responses of an n-port network circuit in terms of S-parameters. This can be used to simplify arbitrarily complex circuits. The Touchstone file can be obtained from numerical simulations or network analyzer measurements. The obtained file for a ... Read More

### Magnetic Frill

Feeding antennas with proper signals can be difficult. The signal is often described as a voltage, and voltages are not well defined in electromagnetic wave formulations. There are several tricks to model voltage generators in such situations, and one is the magnetic frill. This model ... Read More

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