A lossy ferrite circulator at 3GHz is modeled. Geometrical design parameters are varied to match the impedance for minimal reflection of the fundamental TE10 rectangular waveguide mode.
Frequency selective surfaces (FSS) are periodic structures with a bandpass or a bandstop frequency response. This model shows that only signals around the center frequency can pass through the periodic complimentary split ring resonator layer.
A classic benchmark example in computational electromagnetics is to find the resonant frequency and Q-factor of a cavity with lossy walls. Here, models of rectangular, cylindrical, and spherical cavities are shown to be in agreement with analytic solutions.
The dipole antenna is one of the most straightforward antenna configurations. It can be realized with two thin metallic rods that have a sinusoidal voltage difference applied between them. The length of the rods is chosen such that they are quarter wavelength elements at the operating frequency. Such an antenna has a well known torus-like radiation pattern.
RF coils are important in numerous applications ranging from wireless technology to MRI scanning equipment. This introductory tutorial model demonstrates how to find the fundamental resonance frequency of an RF coil as well as how to perform a frequency sweep to extract the coil's Q-factor.
Scientists use the SAR (specific absorption rate) to determine the amount of radiation that human tissue absorbs. This measurement is especially important for mobile telephones, which radiate close to the brain. The model studies how a human head absorbs a radiated wave from an antenna and the temperature increase that the absorbed radiation causes. The increasing use of wireless equipment has ...
This model demonstrates the calculation of the scattering of a plane wave of light off of a gold nanosphere. The scattering is computed for the optical frequency range, over which gold can be modeled as a material with negative complex-valued permittivity. The far-field pattern and the losses are computed.
A plane wave is incident on a wire grating on a dielectric substrate. Coefficients for refraction, specular reflection, and first order diffraction are all computed as functions of the angle of incidence. The model is set up for one unit cell of the grating, flanked by Floquet boundary conditions describing the periodicity. As applied, this condition states that the solution on one side of the ...
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.
The microstrip patch antenna is used in a wide range of applications since it is easy to design and fabricate. The antenna is attractive due to its low-profile conformal design, relatively low cost and very narrow bandwidth. It is known that the antenna impedance will be higher than an accepted value if fed from the edge, and lower if fed from the center. Therefore, an optimum feed point ...