Welcome to Ozen Engineering Webinar

Hello, everybody. Welcome to the OSA Engineering webinar session. Today's topic is Antenna Simulation with ANSYS HFSS. Today, I'll briefly go through the HFSS capability on antenna design and the workflow on the slides.

I'll show the audience hands-on examples on how to do post-processing once you have an antenna simulated and introduce you to a convenient tool, the ANSYS Antenna Design Toolkit. Today, we're focusing on the ANSYS HFSS product, a high-frequency simulation tool.

There are various applications that can be simulated in this tool, including biomedical high-frequency antennas, transmitters, and more. There are three major solvers in this tool: finite element, integral equations, and physics-based simulation.

Each solver has its strengths, and today we'll be using the finite element method, which can efficiently handle complex material geometries and is a volume-based mesh and field solver. The finite element method is a high-frequency structure simulator and a full-wave 3D electromagnetic field solver.

It's also an industry-leading EM simulation tool with strengths in simulation-driven product development, shortening design cycles, and high fidelity on first-pass design success.

Another strength of the ANSYS product is its adaptive mesh refinement, which provides automatic, accurate, and efficient solutions for meshing.

This is different from mechanical and fluid products, as most electromagnetic products in ANSYS use adaptive meshing, so users don't have to do the meshing manually. Now let's look at the integral equation solver.

The technology behind it is a 3D method of moments integral equation technique, where the equation is on the right side of the slide. It uses the equivalence principle to solve only surfaces.

One typical application for this solver is radar or LIDAR on aircraft or helicopters, where the performance on those radars will be affected by the metal shielding of those electrically large vehicles. It can also deal with antenna placement, radar cross-section, and S-parameters.

The advantage of this solver is automated results with accuracy and effective utilization of automated adaptive meshing techniques from HFSS, which is the same for the other solvers. It employs adaptive cross approximation techniques for larger simulations.

In general, this solver is intended to solve large electrical problems. Some other highlights in the HFSS product include pre-testing, parametric modeling, parametric sweep, optimizations, sensitivity, and statistical analysis, as well as integration with ANSYS Design Explorer.

Now let's look at a typical overview of a solution process in HFSS. We start with a design, where we look at the initial project setup. Then, we specify the solution type for the problem, enter the model setup, set materials and boundaries, and create the geometry.

Next, we enter the solution setup and do the analysis, either a frequency sweep or a transient. The software will use adaptive meshing to evaluate the solution, refine itself, and update the solution until it converges. This refinement process is called the automated solution process.

As you can see, we start with the geometry, then have an initial mesh, and the mesh refines itself until we get a converged mesh.

The mashing around the antenna becomes denser and higher quality, and the convergence plot shows that the max magnetic delta S is getting smaller, indicating that the solution isn't changing significantly.

Adaptive meshing provides an accurate, automated, and efficient solution, removing the requirement for manual meshing expertise. Now let's take a look at the software itself. We start with the electronic desktop, a platform for the entire ANSYS electromagnetic product.

Before opening any projects, we set up requirements or options, such as boundary assignment, data input, duplicating boundaries, and more. After opening a project, we insert a new HF Assist design project and decide on the solution type. In this example, we're using the finite element method.

We insert a new project, select the solution type, and set up the airbox, a boundary setup for your problem. Lastly, we set up an excitation, such as a lump port excitation applied to a rectangular area between each arm of the dipole to provide an RF excitation to the antenna element.

Now we can take a look at the software itself. We start with the electronic desktop, where we open a project and set up requirements or options. After setting up the project, we create an open region, which is the airbox we mentioned earlier.

We want this open region to be radiation operating at one gigahertz. After setting up the boundary conditions, we can click on the boundary conditions on the left-hand side of your screen and visualize them.

All boundary conditions defined in the model can be accessed under the Design Boundaries branch in the project manager. Now let's set up a solution and specify the solution frequency, maximum delta S, and maximum number of passes.

The smaller the maximum delta S, the more accurate the solution will be. The maximum number of passes indicates the maximum number of times through the adaptive meshing process before proceeding to the frequency sweep analysis.

After setting up the solution, we can click OK and proceed to set up a frequency sweep. Now everything is all set. We can hit analyze, save the project, and validate the setup. After analyzing, we can look at the solution data to determine whether it's converged or not and how to post-process it.

Now let me switch the window to the actual project. We can kind of understand how to post-process our solutions. We have a dual polarized probe patch antenna. We want to look at whether the solution is convergent. First, we can look at the solution data and go through the data profile.

We can see the number of passes, adaptive passes that converge, and the time elapsed. If the maximum number of passes is less than the set value, the solution is considered converged. We can also generate a plot of S11 versus adaptive pass.

When the S parameters stop changing, it's safe to say that the adaptive meshing process has converged. After checking the convergence, we might want to evaluate the S parameter data. Let's generate a passive S parameter plot, just to give you guys an idea of how to do it.

We can see that at 9 gigahertz, the return loss is about negative 32 dB, which tells us that the antenna will radiate best at 9 gigahertz. Now let's create an active S-parameter.

The difference between an active parameter and a passive S-parameter is that the active S-parameter characterizes the return loss seen at each port given the device's active excitation. For this solution, we have two excitations, which means there are two ports.

The active S-parameter characterizes the return loss seen at each port given the device's active excitation.

When more than one port is simultaneously excited, the signal propagating out of any port consists of the superposition of its own passive self-reflection and a couple of signals from the other ports. The excitation applied to every port is controlled through the HFSS field and added source.

We can access this window by clicking on the source, right-clicking excitation, and selecting added source. For this solution, we don't have the active S-parameter, so we can just simply click on the active S-parameter and see any excitations applied to port two.

If we change the excitation applied to port two, we can see that the S11 has changed. Now let's evaluate the solved fields. Sometimes we want to look at a counter plot of electric field around the antenna based on the solution we just solved.

We can solve the problem of the electric field and then plot the field, selecting magnetic electric field I mean magnitude electric field. By creating this 3D field overlay contour of the electric field magnitude, we can see the electric field around the two ports on the substrate.

From here, we can also generate an animation from the contour plot. This animation can depict the field as the excitation phase progresses from zero degree to 170 degree. The animation can be exported as an AVI or GIS file format. Thank you for attending this webinar.

If you have any further questions, feel free to email support at ozeninc.com. We'll be happy to answer your questions. Wish you a happy and nice day.