Ansys Assistant will be unavailable on the Learning Forum starting January 30. An upgraded version is coming soon. We apologize for any inconvenience and appreciate your patience. Stay tuned for updates.
PCB Design

PCB Design

  1. All Categories
  2. Electronics - PCB Design
  3. In HFSS 3D, the default port impedance is 50 ohms. However, the user may want set the port impedance to a complex number like R-jX ohms to account for matching circuits. At times, if reactance is set in the port settings, it may trigger positive S parameters. In this document we explore how correctly set the port to a non 50-ohm termination and obtain the correct S parameters.

In HFSS 3D, the default port impedance is 50 ohms. However, the user may want set the port impedance to a complex number like R-jX ohms to account for matching circuits. At times, if reactance is set in the port settings, it may trigger positive S parameters. In this document we explore how correctly set the port to a non 50-ohm termination and obtain the correct S parameters.

Tagged: 17.2, Electromagnetics & Electronics, excitations, hfss, Other
    • May 25, 2023 at 7:30 am
      SolutionSolution
      Participant

      To model R-jX ohms for port impedance, the recommended method to modeling complex port impedance is to 1.Divide the port into 3 rectangles; two rectangles for the capacitors and one for the port itself. We use two capacitors instead of one for a balanced feed as shown in the attached PDF. 2.The port and two capacitors are in series. 3.Calculate the capacitance C= 1/(2*pi*f*X) and where X is the imaginary part of the required port impedance. C1 = C2 = 2C 4.The port should be set to the real part of the required port impedance (R) and be normalized to 50 ohms (network analyzer).

      Attachments:
      1. How%20to%20Set-up%20a%20non%2050%20Ohm%20Port.pdf

Featured Articles

Introducing Ansys Electronics Desktop on Ansys Cloud

The Watch & Learn video article provides an overview of cloud computing from Electronics Desktop and details the product licenses and subscriptions to ANSYS Cloud Service that are...

How to Create a Reflector for a Center High-Mounted Stop Lamp (CHMSL)

This video article demonstrates how to create a reflector for a center high-mounted stop lamp. Optical Part design in Ansys SPEOS enables the design and validation of multiple...

Introducing the GEKO Turbulence Model in Ansys Fluent

The GEKO (GEneralized K-Omega) turbulence model offers a flexible, robust, general-purpose approach to RANS turbulence modeling. Introducing 2 videos: Part 1 provides background information on the model and a...

Postprocessing on Ansys EnSight

This video demonstrates exporting data from Fluent in EnSight Case Gold format, and it reviews the basic postprocessing capabilities of EnSight.

© 2026 Copyright ANSYS, Inc. All rights reserved.