# Application Gallery

The Application Gallery features COMSOL Multiphysics tutorial and demo app files pertinent to the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use tutorial models and demo apps with step-by-step instructions for how to create them yourself. The examples in the gallery serve as a great starting point for your own simulation work.
Use the Quick Search to find tutorials and apps relevant to your area of expertise. Log in or create a COMSOL Access account that is associated with a valid COMSOL license to download the MPH-files.

### Balanced Patch Antenna for 6 GHz

Patch antennas are becoming more common in wireless equipment, like wireless LAN access points, cellular phones, and GPS handheld devices. The antennas are small in size and can be manufactured with simple and cost-effective techniques. Due to the complicated relationship between the geometry of the antenna and the electromagnetic fields, it is difficult to estimate the properties of a certain ...

### Coaxial to Waveguide Coupling

Feeding a waveguide from a coaxial cable is a straightforward way to achieve electromagnetic waves inside a waveguide. Due to its small size and circular shape, the cable contributes significantly to the overall size of the problem. It is therefore necessary to keep the cable as short as possible. This model shows how to use pairs and the Port boundary conditions to feed a rectangular ...

### 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.

### 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 ...

### 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.

### Two-Arm Helical Antenna

A helical antenna has two major modes. One is normal mode and the other is axial mode. When the helical antenna is operating at the normal mode, its far-field radiation pattern is similar to the torus shaped pattern of a classic dipole antenna. At the axial mode, the helical antenna is resonant at a much higher frequency band than the normal mode operation, and works similarly to an end-fire ...

### Dipole Antenna with a Quarter-Wave Coaxial Balun

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 ...

### 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.

### Biconical Antenna

A Biconical antenna is a type of wideband antenna with omni-directional radiation pattern in the H-plane similar to a dipole antenna. A coaxial feed is connected to the radiators using two 90 degree bent arms. The model shows that the biconical antenna works well in applications requiring an omnidirectional radiation pattern and wide bandwidth.

### Tunable Evanescent Mode Cavity Filter Using a Piezo Actuator

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.