Microwave Heating of a Cancer Tumor
Electromagnetic heating is ideally suited for modeling in COMSOL Multiphysics. This model shows the area of hyperthermic oncology but the modeling issues and techniques are generally applicable to any problem involving electromagnetic heating. The purpose of this model is to compute the radiation field and the Specific Absorption Rate (SAR) in liver tissue for a thin coaxial slot antenna used ...
Radar Cross Section
This tutorial model demonstrates the use of a background field in an electromagnetic scattering problem. Although this example is a boat hit by a radar, this same technique can be used in any situation where an isolated object meets electromagnetic waves from a distant source. For example, several orders of magnitude smaller, an equally common application is plasmon resonant nanoparticles. ...
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 ...
Fresnel Equations (RF)
A plane electromagnetic wave propagating through free space is incident at an angle upon an infinite dielectric medium. This model computes the reflection and transmission coefficients and compares to the Fresnel equations.
Coplanar Waveguide Bandpass Filter
Coplanar waveguide (CPW) bandpass filters can be designed using interdigital capacitors (IDCs) and short-circuited stub inductors (SSIs). This is a very efficient manufacturing method for producing bandpass filters, which can readily be implemented on a GaAs wafer. The Coplanar Waveguide Bandpass Filter tutorial model presents a design that is compact in relation to its resonant frequency and ...
H-Bend Waveguide 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 ...
MRI Birdcage Coil
Magnetic resonance imaging (MRI) systems generate a magnetic flux density (B-field) to create images. Providing a homogeneous field distribution within a birdcage coil is a key factor for improving the quality of the scanned data. A homogeneous magnetic field can be found through quadrature excitation, in combination with the appropriate number of lumped elements. In this model, the magnetic ...
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.
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.
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 ...
