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See what market experts predict for various markets related to SI, PI and EMI applications.

Catching the Wave: Perfect Your Port Designs

August 24, 2021

Fueled by 5G, artificial intelligence, product autonomy, augmented reality and the growth of consumer applications like Zoom and Netflix, global demand for faster data rates is an urgent pressure. Developers of high-speed, high-performance interconnect solutions, need to rapidly and continuously innovate to keep the world’s data centers running as fast, and as reliably, as possible.

For  engineering teams, that means optimizing signal channels to deliver reliable product performance at data rates of 224 Gbps and above. As electronics package sizes become smaller and more densely packed, it is necessary to optimize the entire signal path to reduce signal loss and eliminate interference. 

Samtec does not develop “off the shelf” commodity interconnect solutions; instead, it designs niche products that meet highly specific customer needs. Since 2010, Samtec has relied on port modeling capabilities in Ansys HFSS to make tradeoffs and optimize its interconnect designs in a risk-free virtual landscape. Using simulation instead of iterative physical prototypesmakes it possible to cut significant time and costs from this customized design process, while also supporting a high level of product innovation. 

Perfecting the Port to Improve Accuracy and Performance

Every element of the interconnect design process is critical in supporting multi-gigabit per second performance. When simulating interconnect designs with Ansys HFSS, ports are an especially important consideration. The port definition can have a significant impact on the simulation response from HFSS and, if not defined properly, can lead to errors. With proper port definition, the models extracted from an HFSS simulation can be effectively used in a broader system-level simulation. By optimizing their port setups, Samtec engineers can confidently design for multi-frequency applications and high data rates in the smallest possible technology packages, with optimized signal transmission.

This means making thoughtful decisions at certain stages of the simulation. For example, the size of a port is a critical consideration. Ports need to be large enough to correctly capture the transmission line field behavior, or the “wave” along a connector’s nets, but not so large as to electromagnetically interfere directly with the electromagnetic fields of the connector itself. If the port size is incorrectly defined, characteristic impedance and unphysical reflections may result, creating unacceptable and incorrect signal losses through mismatch. Given the much tighter tolerances in device design today, providers must deliver more exacting, highly optimized engineering connector models for every design ― and proper HFSS port definitions are key to achieving this goal.

Ansys HFSS leverages a variety of port types — including lumped ports and circuit ports ― but Samtec particularly relies on Ansys’ wave port technology for modeling accurate, well matched feeds to its high-speed connector designs. Samtec is an expert user of this capability and recently co-presented a webinar with Ansys featuring “tips and tricks” on wave port modeling.

By applying the Transfinite Element Method to wave ports, Ansys HFSS supports a robust level of analysis. Ansys HFSS enables exact numerical port truncation with a very low noise floor. For computational efficiency, the HFSS simulation engine is capable of automatically and directly solving only for S-parameters, so engineers can quickly identify, understand, and address performance degradation caused by wave scattering. When electromagnetic (EM) engineers use tools that do not leverage the Transfinite Element Method, this calculation is much more time-consuming and less accurate, with a higher noise floor.

The wave port solver in Ansys HFSS enables performance predictions that replicate real-world physical testing. This enables Samtec to meet the highly precise performance expectations of the world’s leaders in data center technology. When these high tech manufacturers also utilize wave ports in their advanced designs, the resulting technology platform has the signal integrity to easily support ambitious data speeds of 224 Gbps and above.

More Information   

To learn more about the theoretical basis of various port types, and how to use them in real designs to deliver maximum accuracy, watch the on-demand webinar, “Practical Ports for Perfect Performance,” co-hosted by Samtec and Ansys. While this webinar does highlight expert wave port modeling practices that were pioneered by Samtec, it covers other port types as well.

You can also learn more about the role played by various design components — including ports, meshes and boundary conditions ― in optimizing signal integrity by enrolling in “Ansys HFSS 3D Components” at the Ansys Training Center. This on-demand course covers fundamental concepts in fully arbitrary 3D electromagnetic simulation via Ansys HFSS. Port-specific topics include wave port sizing, 2D port fields, modes, integration lines and de-embedding. 



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