A bowtie antenna patterned on a dielectric substrate is optimized by changing the length of the arms and the flare angle to reduce the magnitude of S11, the reflection coefficient. The two geometric dimensions that are used as design...
A cascaded cavity filter provides much better bandpass filter performance compared to a single cavity. Out-of-band rejection improves dramatically using a cascaded design. This model uses three rectangular cavity filters coupled via...
This model of a circular waveguide demonstrates how to use ports with numerical solution of the port modes. It illustrates how to align the polarization of degenerate port modes and in particular how to model and excite the TE11 mode of...
A Branch Line Coupler (Quadrature 90° Hybrid) is a four-port network device with a 90° phase difference between two coupled ports. The device can be used for a single antenna Transmitter/Receiver system or an I/Q signal...
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...
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.
A bird-cage coil is used in Magnetic Resonance Imaging (MRI) applications as a receiving antenna. This particular coil would sit around limbs and be used to scan a leg or arm. The COMSOL Multiphysics with RF Module model...
Laser systems are an important application area in modern electronics. There are several ways to generate a laser beam, but they all have one thing in common: the wavelength is determined by the stimulated emission, which depends on...
Transmission lines are used when the frequency of the electromagnetic signals is so high that the wave nature of the signals must be taken into account. A consequence of the wave nature is that the signals are reflected if there are...
A spiral slot antenna provides a conformal design and can be used for communication, sensing, tracking, positioning, and many applications in different microwave frequency bands due to its wide-band frequency response. This model shows...
