Items Tagged with 'transmission line'

ARTICLES

thumb rev

Those Pesky Half-Wave Resonances

“Over the years I’ve come to realize that, particularly in signal integrity, half-wave resonances are often the cause of ugly S-parameters. You can argue that any type of resonance would cause problems, and you would be right. However, half-wave resonances are easily formed in topologies.” This article summarizes observations from Gustavo Blando on the formation and mitigation of half-wave resonances, and includes an in-depth study on the topic in PDF format from the author.


Read More
Bert_4597 Thumb

Stackup Beware: Case Study of the Effects on Transmission Line Losses Due to Mixed Reference Plane Roughness

Designing the right PCB stackup can make or break product performance. If the product has circuitry that is impedance and transmission loss sensitive, then paying attention to conductor surface roughness is paramount. Sometimes, however, the roughness of adjacent reference plane(s) is overlooked. If the adjacent high-speed signal layer uses smoother copper than one or both reference planes, a higher insertion loss than expected for that layer will occur and possibly cause a product to fail compliance. So, how is this determined before finalizing the stackup? Read on to find out.


Read More
Thumb

A Guide for Single-Ended to Mixed-Mode S-parameter Conversions

Signal integrity engineers almost always have to work with S-parameters. If you have not had to work with them yet, then chances are you will sometime in your career. As speed moves up in the double-digit GB/s regime, many industry standards are moving to serial link-based architectures and are using frequency domain compliance limits based on S-parameter measurements.


Read More
thumb rev

How to Reduce Attenuation in a Differential Channel

The attenuation in a uniform differential pair has two root causes: conductor loss and dielectric loss. By understanding how design decisions affect these two fundamental root causes, we can develop a few simple guiding principles which point us in the right directions to reduce the attenuation of a channel. These are the directions to follow when loss is important. In some cases, increasing the differential impedance will decrease loss, and in some cases it will increase the loss. Read on to see why.


Read More