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Characteristic Parameters of a Coaxial Cable
Electrical cables, also called transmission lines, are used everywhere in the modern world to transmit both power and data. These cables carry electromagnetic energy, but instead of dealing with the full complexity of the electromagnetic fields, they are more commonly classified according to parameters such as capacitance, inductance, and impedance. In this model of a coaxial cable, we ...
Log-Periodic Antenna
The shape of a log-periodic antenna resembles that of a Yagi-Uda antenna, but is composed of a coplanar array to achieve a wider bandwidth. It is also known as a wideband or frequency-independent antenna. All metallic parts are modeled using the perfect electric conductor (PEC) boundary conditions. The antenna is excited by a lumped port while a lumped element with a resistor is used to ...
Transmission Line Butler Matrix Beamforming Network
A Butler matrix is a passive beamforming feed network. It is a cost-effective feed network for phased array antennas because the circuit can be fabricated in the form of microstrip lines and is a viable solution for performing beam scanning without deploying expensive active devices. This example shows how to design such a circuit using the *Transmission Line* interface. The results show the ...
Double-Ridged Horn Antenna
A double-ridged horn antenna is popularly used in anechoic chambers to characterize an antenna under test (AUT), from S-band to Ku-band, due to its reliable performance in a wideband frequency range. This tutorial models a double-ridged horn antenna and computes the voltage standing wave ratio (VSWR), far-field radiation pattern, and antenna directivity. A lumped port is assigned on the ...
Rat-Race Coupler
A 180° Ring Hybrid (Rat-Race Coupler) is a four-port network with 180° phase difference between two ports. It is cheaper to manufacture this type of microstrip line component compared to a wave guide 180° hybrid junction, so called magic-T. The objective of this model is to compute the S-parameters and to observe the matching, isolation, and coupling around the operating frequency.
Radome with Double-layered Dielectric Lens
A radome minimizes losses and improves radiation characteristics of an antenna through its design. The structure can be optimized to minimize the transmission loss and also designed to improve radiation characteristics including antenna directivity and side lobes. Shown in the model is the surface current density on the patch antenna, the magnitude of the electric potential on the antenna's ...
Time-Domain Modeling of Dispersive Drude-Lorentz Media (RF)
This tutorial shows how to solve the full time-dependent wave equation in dispersive media such as plasmas and semiconductors. The 2D TM in-plane wave model solves for the vector potential from the wave equation and for an auxiliary electric polarization density from an ordinary differential equation. The geometry consists of a single dispersive slab with a sub-wavelength slit in it. Periodic ...
Fast Numerical Modeling of a Conical Horn Lens Antenna
An axisymmetric 3D structure such as a conical horn antenna can be simulated in a fast and efficient way using only its 2D layout. In this model, the antenna radiation and matching characteristics are computed very quickly with respect to the dominant TE mode from the given circular waveguide by simulating the 2D axisymmetric geometry of an 3D antenna structure.
Time-to-Frequency Fast Fourier Transform of a Coaxial Low-Pass Filter
A very wide band coaxial low-pass filter is designed using a 2D axisymmetric model. To address the wide band frequency response with a fine frequency resolution, the model is built with a transient physics interface first. Then, S-parameters are calculated using a time-to-frequency Fourier transform. To achieve a low-pass frequency response, an air-filled coaxial cable is tuned with five ...
Car Windshield Antenna Effect on a Cable Harness
Modern cars have rear-windshield FM antennas to play FM radio. The radiation emitted from an antenna induces an electric current on the outer surface of any cable harnesses in the car, which can have negative effects. This model uses the RF Module to compute the far-field radiation pattern of the antenna, by enclosing the car in perfectly matched layers separated by an air domain. The electric ...
