HFSS: Conical Horn Antenna Simulation

For the following simulation, the solution type is Driven Modal. Driven modal gives solutions in terms of power, as opposed to Driven Terminal which displays results in terms of voltages and currents. The units are set to inches.

The first step is to create the circular waveguide with a radius of .838 inches and a height of three inches:


To make the building process easier, a relative coordinate system is implemented through the Modeler window. The coordinate system is moved up to z = 3. A conical transition region (taper) is built at that origin point. The lower radius is 0.838 and the upper radius is 1.547. The height is 1.227. The coordinate system is then adjusted to be on top of the taper.


The “throat” is created by placing yet another cylinder on top of the taper. The height is 3.236. Now, all the objects are selected and a Boolean unite is performed. All units can be selected by using the shortcut “CTRL + A”. From this point, a single object is obtained and name “Horn_Air”. This can be seen in the project tree on the left.


The coordinate system is displaced back to the standard origin and “pec” is selected as the default material (perfect electrical conductor). This will be used to create the horn wall, shown below. A Boolean subtract is performed between the vacuum parts and the conductive portion to create a hollowed out antenna.


Because the simulation is of a radiating antenna, an air box of some sort must be implemented. In our case, we use a cylindrical radiation boundary. The bottom of the device is chosen for the waveport. Upon assigning the two mode waveport, the coordinate system is redefined for the radiation setup. For the radiation, the azimuthal angle is incremented from 0 to 90 in one 90 degree increment and the elevation angle is incremented from -180 to 180 with a step size of 2:


The simulation is done at 5 GHz with 10 as the maximum number of passes. The S-Matrix data is shown below.


As well as the convergence plot:


The radiation pattern is shown for the gain below:


The plot is in decibels and is swept over the elevation angle. Both the lefthand and righthand polarized circular wave patterns are shown at angles phi = 90 and phi = 0. The two larger curves are the RHCP and the two smaller are LHCP.

HFSS – Simulation of a Square Pillar

The following is an EM simulation of the backscatter of a golden square object. This is by no means a professional achievement, but rather provides a basic introduction to the HFSS program.


The model is generated using the “Draw -> Box” command. The model is placed a distance away from the origin, where the excitation is placed, shown below. The excitation is of spherical vector form in order to generate a monostatic plot.


The basic structure is a square model (10mm in all three coordinates) with an airbox surrounding it. The airbox is coated with PML radiation boundaries to simulate a perfectly matched layer. This is to emulate a reflection free region. This is necessary to simulate radiating structures in an unbounded, infinite domain. The PML absorbs all electromagnetic waves that interract with the boundary. The following image is the plot of the Monostatic RCS vs the Incident wave elevation angle.


The subsequent figure was generated by using a “bistatic” configuration and is plotted against the elevation angle.


HFSS RCS Backscatter Analysis

RF/Photonics Lab UMASS Dartmouth, Advisor Dr. Yifei Li
October 2019
Michael Benker
HFSS RCS Backscatter

Below is an RCS backscatter simulation of a cylinder up to 100 GHz. The main goal of this task was to gain a comfort level using HFSS to perform further RCS backscatter simulations in the future. Using HFSS has been interesting, especially due to the amount of computing strength it may require at times. I look forward to using this program more in the future.

Attached is also a PDF guide (not my own) that can be useful for performing a similar simulation: Getting_Started_with_HFSS