Galleria dei Modelli

La Galleria dei Modelli raccoglie un'ampia varietà di modelli realizzati con COMSOL Multiphysics in diversi ambiti applicativi, inclusi quelli elettrico, meccanico, fluidico e chimico. E' possibile scaricare i file .mph dei modelli pronti all'uso e le istruzioni step-by-step per costruirli, e utilizzarli come punto di partenza per le proprie simulazioni. Lo strumento di Ricerca Rapida permette di trovare i modelli che si riferiscono alla propria area di interesse. Per scaricare i file .mph dei modelli è necessario effettuare il login o creare un account COMSOL Access associato a un numero di licenza valido.

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.

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 an ...

Second Harmonic Generation of a Gaussian Beam

Laser systems are an important application area in modern electronics. With nonlinear materials it is possible to generate harmonics that are a multiple of the frequency of the laser light. This model shows how a second harmonic generation can be set up as a transient wave simulation, using nonlinear material properties. A YAG (lambda=1.06 microm.) laser beam is focused on a nonlinear ...

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 ...

Electromagnetic and Structural Analysis of a Microwave Filter on a PCB

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 microstrip line, the impedance of the stub microstrips, and the length of the stubs. This particular filter ...

Step Index Fiber

The transmission speed of optical waveguides is superior to microwave waveguides, because optical devices have a much higher operating frequency than microwaves, enabling a far higher bandwidth. This model is an example of a single step-index waveguide made of silica glass. The inner core is made of pure silica glass with refractive index n1 = 1.4457 and the cladding is doped, with a refractive ...

Modeling of Pyramidal Absorbers for an Anechoic Chamber

In this model, a microwave absorber is constructed from an infinite 2D array of pyramidal lossy structures. Pyramidal absorbers with radiation-absorbent material (RAM) are commonly used in anechoic chambers for electromagnetic wave measurements. Microwave absorption is modeled using a lossy material to imitate the electromagnetic properties of conductive carbon-loaded foam.

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 ...

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.

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 ...

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