An example of a User-Defined Lumped Port geometry. This option is appropriate if you need to manually enter these settings, like in the geometry shown below and as demonstrated in this example of a dipole antenna. The User-Defined option allows you to manually enter the height and width of the feed, as well as the direction of the electric field vector. Uniform Lumped Ports are commonly used to excite striplines and coplanar waveguides, as discussed in detail here.
![cst microwave studio for low frequencies edaboard cst microwave studio for low frequencies edaboard](http://www.mweda.com/cst/cst2013/mergedprojects/cst_microwave_studio/special_overview/debye1st.png)
Cst microwave studio for low frequencies edaboard software#
The electric field is assumed to be uniform in magnitude between the bounding faces, and the software automatically computes the height and width of the Lumped Port face, which should always be much smaller than the wavelength in the surrounding material. The Uniform option can be used if you have a geometry as shown below: a surface bridging the gap between two electrically conductive faces. For a coaxial cable, we always need to apply the boundary condition at an annular face, but we can also use the Lumped Port boundary condition in other cases. The excitation options for this condition are that the excitation can be specified in terms of a cable impedance along with an applied voltage and phase, in terms of the applied current, or as a connection to an externally defined circuit. So, since we know the shape of the electric field at the cross section of a coax, we can apply this as a boundary condition using the Lumped Port, Coaxial boundary condition. However, there also exists an analytic solution for this problem.
![cst microwave studio for low frequencies edaboard cst microwave studio for low frequencies edaboard](https://reizeclub.com/wp-content/uploads/2020/12/feat2.jpeg)
That is, the electric and magnetic fields both lie entirely in the cross-sectional plane. Over its range of operating frequencies, a coax operates in Tranverse Electro-Magnetic TEM mode, meaning that the electric and the magnetic field vectors have no component in the direction of wave propagation along the cable. A coaxial cable is a waveguide composed of an inner and outer conductor with a dielectric in between. We can begin our discussion of the Lumped Port boundary condition by looking at the fields in a coaxial cable. Let us look at what these boundary conditions mean and when they should be used. These situations call for the use of the Lumped Port and the Port boundary conditions.
![cst microwave studio for low frequencies edaboard cst microwave studio for low frequencies edaboard](https://i.redd.it/91ajvcokk2471.jpg)
There are many other such cases where we know the form but not the magnitude or phase of the electromagnetic fields at some boundaries of our modeling domain. We know that the electromagnetic fields in the incoming and outgoing cables will have a certain form and that the energy is propagating in the direction normal to the cross section of the coax. Consider, for example, a coaxial splitter as shown herewhich splits the signal from one coaxial cable coax equally into two.
![cst microwave studio for low frequencies edaboard cst microwave studio for low frequencies edaboard](https://www.3ds.com/typo3temp/pics/frequency-domain-solver-cst-st_2b9c6a38b7.png)
When modeling electromagnetic structures e. When using the COMSOL Multiphysics software to simulate wave electromagnetics problems in the frequency domain, there are several options for modeling boundaries through which a propagating electromagnetic wave will pass without reflection. By continuing to use our site, you agree to our use of cookies. This website uses cookies to function and to improve your experience.