“Equation Based Surface” for Conformal and Non-Planar Antenna Design

ANYSY HFSS provides many options for creating non-planar and conformal shapes. In MCAD you may use shapes such as cylinders or spheres, and with some steps, you can design you antennas on various surfaces. In some applications, it is necessary to study the effect of curvatures and shapes on the antenna performance. For example for wearable antennas it is important to study the effect of bending, crumpling and air-gap between antenna and human body.

Equation Based Surface

One of the tools that HFSS offers and can be used to do parametric sweep or optimization, is “Draw equation based surface”. This can be accessed under “Draw” “Equation Based Surface” or by using “Draw” tab and choosing it from the banner (Fig. 1)

Fig. 1. (a) Select Draw -> Equation Based Surface
Fig. 1. (b) click on the icon that is highlighted

Once this is selected the Equation Based Surface window that opens gives you options to enter the equation with the two variables (_u, _v_) to define a surface. Each point of the surface can be a function of (_u,_v). The range of (_u, _v) will also be determined in this window. The types of functions that are available can be seen in “Edit Equation” window, by clicking on “…” next to X, Y or Z (Fig. 2). Alternatively, the equation can be typed inside this window. Project or Design Variables can also be used or introduced here.

Fig. 2. (a) Equation Based Surface window
Fig. 2. (b) Clikc on the “…” next to X and see the “Edit Equation: window to build the equation for X

For example an elliptical cylinder along y axis can be represented by:

This equation can be entered as shown in Fig. 3.

Fig. 3. Elliptical surface equation

Variation of this equation can be obtained by changing variables R1, R2, L and beta. Two examples are shown in Fig. 4.

Fig. 4. Elliptical surface equation

Application of Equation Based Surface in Conformal and Non-Planar Antennas

To make use of this function to transfer a planar design to a non-planar design of interest, the following steps can be taken:

  • Start with a planar design. Keep in mind that changing the surface shape can change the characteristics of the antenna. It is a good idea to use a parameterized model, to be able to change and optimize the dimensions after transferring the design on a non-planar surface. As an example we started with a planar meandered line antenna that works around 700MHz, as shown in Fig. 5. The model is excited by a wave port. Since the cylindrical surface will be built around y-axis, the model is transferred to a height to allow the substrate surface to be made (Fig 5. b)
Fig. 5. Planar meandered antenna (a) on xy plane, (b) moved to a height of 5cm
  • Next, using equation based surface, create the desired shape and with the same length as the planar substrate. Make sure that the original deisgn is at a higher location. Select the non-planar surface. Use Modeler->Surface->Thicken Sheet … and thicken the surface with the substrate thickenss. Alternatively, by choosing “Draw” tab, one can expand the Sheet dropdown menu and choose Thicken Sheet. Now select the sheet, change the material to the substrate material.
Fig. 6. Thicken the equation based surface to generate the substrate
  • At this point you are ready to transfer the antenna design to the curved surface. Select both traces of the antenna and the curved substrate (as shown in Fig. 7). Then use Modeler->Surface->Project Sheet…, this will transfer the traces to the curved surface. Please note that the original substrate is still remaining. You need not delete it.
Fig. 7. Steps for transferring the design to the curved surface (a)

Fig. 7. Steps for transferring the design to the curved surface (b)

Fig. 7. Steps for transferring the design to the curved surface (c)
  • Next step is to generate the ground plane and move the wave port. In our example design we have a partial ground plane. For ground plane surface we use the same method to generate an equation based surface. Please keep in mind that the Z coordinate of this surface should be the same as substrate minus the thickness of the substrate. (If you thickened the substrate surface to both sides, this should be the height of substrate minus half of the substrate thickness). Once this sheet is generate assign a Perfect E or Finite Conductivity Boundary (by selecting the surface, right click and Assign Boundary). Delete the old planar ground plane.
Fig. 8. Non-planar meandered antenna with non-planar ground

Wave Port Placement using Equation Based Curve

A new wave port can be defined by the following steps:

  • Delete the old port.
  • Use Draw->Equation Based Curve. Mimicking the equation used for ground plane (Fig. 9).
Fig. 9. Use Equation Based Curve to start a new wave port (a) Equation Based Curve definition window (b) wave pot terminal created using equation based curve and sweep along vector
  • Select the line from the Model tree, select Draw->Sweep->Along Vector. Draw a vector in the direction of port height. Then by selecting the SweepAlongVector from Model tree and double clicking, the window allows you to set the correct size of port height and vector start point (Fig. 10).
  • Assign wave port to this new surface.
Fig. 10. Sweep along vector to create the new wave port location

Similar method can be used to generate (sin)^n or (cos)^n surfaces. Some examples are shown in Fig. 11. Fig. 11 (a) shows how the surface was defined.

Fig. 11. (a) Equation based surface definition using “cos” function, (b), (c), & (d) three different surfaces generated by this equation based surface.

Effect of Curvature on Antenna Matching

Bending a substrate can change the transmission line and antenna impedance. By using equation based port the change in transmission line impedance effect is removed. However, the overall radiation surface is also changed that will have effects on S11. The results of S11 for the planar design, cylindrical design (Fig. 8), cos (Fig. 11 b), and cos^3 (Fig. 11 c) designs are shown in Fig. 12. If it is of interest to include the change in the transmission line impedance, the port should be kept in a rectangular shape.

Fig. 12. Effect of curvature on the resonance frequency.

Equation based curves and surfaces can take a bit of time to get used to but with a little practice these methods can really open the door to some sophisticated geometry. It is also interesting to see how much the geometry can impact a simple antenna design, especially with today’s growing popularity in flex circuitry. Be sure to check out this related webinar  that touches on the impact of packaging antennas as well. If you would like more information on how these tools may be able to help you and your design, please let us know at info@padtinc.com.

You can also click here to download a copy of this example.

All Things ANSYS 034 – Celebrating 25 Years of ANSYS Simulation: Changes In The Last Quarter Century & Where The Future Will Take Us

 

Published on: April 8th, 2019
With: Eric Miller, Ted Harris, Tom Chadwick, Sina Ghods, & Alex Grishin
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Ted Harris, Tom Chadwick, Sina Ghods, and Alex Grishin, for a round-table discussion on their experience and history with simulation, including what has changed since they started using it and what they’re most impressed and excited by, followed by some prediction and discussion on what the future may hold for the world of numerical simulation.

Thank you again for those of you who have made the past 25 years something to remember, and to those of you who have come to know PADT more recently, we look forward to what the next 25 will bring.

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All Things ANSYS 033 – Using ANSYS Simulation to Disrupt the World of Capacitor Technology

 

Published on: March 25th, 2019
With: Eric Miller & Sean Katsarelis
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by Sean Katsarelis form Polycharge for a discussion on how they leverage the ANSYS Startup Program and simulation tools to disrupt the world of capacitor technology.

Listen as they discuss the various capabilities and applications best suited for this market, along with updates on the worlds of PADT and ANSYS.

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Introducing ANSYS 2019 R1

PADT is excited to announce the release of ANSYS 2019 R1, the first group of updates for the suite of ANSYS simulation software this year. The release features updates for a wide variety of applications, including simulation for fluids, structures, electronics, 3D design, and much more.

We will be hosting a series of live webinars over the course of 2019 that will allow you to learn about what’s new in this release, from PADT’s team of expert support engineers.

Take a look at the following upcoming product update webinars for 2019 R1 and register by clicking the links below.

There is more to come, so stay tuned


Fluent Updates in ANSYS 2019 R1
Wednesday, February 13th – 11:00 am – 12:00 pm MST AZ

Computational Fluid Dynamics (CFD) is a tool with amazing flexibility, accuracy and breadth of application. Serious CFD, the kind that provides insights to help you optimize your designs, could be out of reach unless you choose your software carefully. Experienced engineers need to go further and faster with well-validated CFD results across a wide range of applications, and with ANSYS Fluent users are able to do just that; delivering reliable and accurate results.

Join Padt’s CFD Team Lead Engineer, Clinton Smith for a look at what new capabilities are available for the latest version of Fluent, in ANSYS 2019 R1.

Register Here


Mechanical Updates in ANSYS 2019 R1
Wednesday, March 13th – 11:00 am – 12:00 pm MST AZ

From designers and occasional users looking for quick, easy, and accurate results, to experts looking to model complex materials, large assemblies, and nonlinear behavior, ANSYS Mechanical enables engineers of all levels to get answers fast and with confidence. With applications for everything form strength analysis to topology optimization, it’s no wonder this comprehensive suite of tools continues to serve as the flagship mechanical engineering software solution.

Join PADT’s Simulation Support Manager, Ted Harris for a look at what new capabilities are available for ANSYS Mechanical, in the latest version; 2019 R1.

Register Here


High Frequency Electromagnetics Updates in ANSYS 2019 R1
Wednesday, April 10th – 11:00 am – 12:00 pm MST AZ

In today’s world of high performance electronics and advanced electrification systems, the effects of electromagnetic fields on circuits and systems cannot be ignored. ANSYS software can uniquely simulate electromagnetic performance across component, circuit and system design, evaluating temperature, vibration and other critical mechanical effects.

Join PADT’s Electrical Engineer, Michael Griesi for a look at what new capabilities are available with regards to High Frequency Electromagnetics, in the latest version of ANSYS; 2019 R1

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Discovery Updates in ANSYS 2019 R1
Wednesday, May 8th – 11:00 am – 12:00 pm MST AZ

The ANSYS 3D Design family of products enables CAD modeling and simulation for all design engineers. Since the demands on today’s design engineer to build optimized, lighter and smarter products are greater than ever, using the appropriate design tools is more important than ever.

Join PADT’s Simulation Support Manager, Ted Harris for a look at what exciting new features are available for design engineers in both Discovery Live and AIM, in ANSYS 2019 R1.

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You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!


All Things ANSYS 028 – A Year in Review: Predictions for ANSYS in 2019

 

Published on: January 7th, 2019
With: Eric Miller, Joe Woodward, & Ted Harris
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Simulation Support Manager Ted Harris, and Specialist Mechanical Engineer Joe Woodward, for a discussion on their predictions for ANSYS in 2019, and a look back at our predictions from 2018.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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All Things ANSYS 024 – An Interview with TriLumina on using ANSYS to help develop LiDAR components

 

Published on: November 5th, 2018
With: Eric Miller & Jeff Earls
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by Jeff Earls of TriLumina for a discussion on how they use ANSYS simulation tools on their disruptive new design for laser arrays used in LiDAR applications, such as autonomous vehicles. All that, followed by an update on news and events in the respective worlds of ANSYS and PADT.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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All Things ANSYS 023 – Exploring the Latest & Greatest in ANSYS 19.2

 

Published on: October 22nd, 2018
With: Eric Miller, Joe Woodward, Ted Harris, & Tom Chadwick
Description:  

In this episode the technical support staff at PADT returns to join your host and Co-Founder of PADT, Eric Miller for a discussion on their favorite additions in ANSYS 19.2. This conversation includes PADT’s Specialist Mechanical Engineer Joe Woodward, Simulation Support Manager Ted Harris, & Senior CFD Engineer Tom Chadwick, and is followed by an update on news and events in the respective worlds of ANSYS and PADT.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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All Things ANSYS 021 – Introducing the ANSYS Innovation Conference

 

Published on: September 24th, 2018
With: Eric Miller, Arkajyoti Chang, Chris Grieve, Aaron Edwards, and Andy Bauer
Description: In this episode your host and Co-Founder of PADT, Eric Miller is joined by Arkajyoti Chang of Benchmark Electronics, Chris Grieve of Optis World, and Aaron Edwards & Andy Bauer of ANSYS Inc., for a discussion on where their companies fit into the world of simulation, focusing on applications such as autonomous vehicles, chip packaging, antenna design, and more, as well as a brief synopsis of what they will be discussing at the upcoming Arizona ANSYS Innovaiton Conference on Wednesday, October 3rd. All that, followed by an update on news and events in the respective worlds of ANSYS and PADT.

For more information on the Arizona ANSYS Innovation Conference & a link to register visit: https://www.padtinc.com/AZInnovation18.html

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How to Accelerate & Simplify your Antenna Impedance Matching Network Design – Webinar

Don’t miss this informative presentation – Secure your spot today!
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All Things ANSYS 012 – Live From New Mexico: A Look at What’s New in ANSYS 19

 

Published on: January 30, 2018
With: David Mastel, Joe Woodword, Manoj Mahendran, Matt Sutton, Michael Griesi, Tom Chadwick, Ted Harris, Eric Miller
Description: In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s David Mastel, Joe Woodword, Manoj Mahendran, Matt Sutton, Michael Griesi, Tom Chadwick, and Ted Harris, for a discussion on what is new and improved in the recently released ANSYS 19.
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Introducing the 2017 ANSYS Arizona Innovation Conference

As the world of manufacturing continues to grow and change, engineers are being challenged to design, test, and evaluate products in increasingly complex environments. In such a time it is necessary to rely on an all-encompassing simulation platform that can handle a variety of physics efficiently, operating as a one stop shop for complete virtual prototyping. ANSYS is that platform!

Join us for this informative seminar including presentations from customers and ANSYS technical experts, focusing on how to effectively implement the ANSYS platform and productivity enhancement tools into your work-flow.

Through this free event we hope to inform you on how a single consolidated platform for complete virtual prototyping can help to drive efficiency across your company!

Date: October 4, 2017

Time: 9:00 AM – 4:30 PM MST AZ

Location: ASU SkySong – Building 3
1365 N. Scottsdale Rd.
Scottsdale, AZ 85257

Check out the full agenda, with presentations covering a plethora of topics including:

  • ANSYS Solutions for Additive Manufacturing
  • Wireless Connectivity with RF Engineering
  • Commercial Antenna Array Work Flow Using ANSYS Electromagnetic Tools

This event will include presentations from customers and ANSYS technical experts alike, focusing on how to effectively implement the ANSYS platform and productivity enhancement tools into your work-flow.

We look forward to seeing you there – Secure your spot today!