The Impact of Plated Through Hole Via’s on RF Performance

Plated through hole (PTH) via’s are commonly used for RF Printed Circuit Board (PCB) applications. The use of PTH via’s for grounding or repetitive grounding is typically less concerning, however when PTH via’s are used to transition a signal trace from one copper layer to another, the via property can have a significant impact on signal integrity. This webinar will give an overview of several studies done to evaluate the impact of PTH via’s on RF performance when transitioning the signal trace to different copper layers within a multilayer PCB. The agenda is:

• Basics of RF transmission line circuitry
• Overview of the RF properties of a simple PTH via
• Variables associated with obtaining accurate impedance measurements
• Details of the test vehicle used in this study
• Signal launch experiments
• Measured RF data showing different PTH via designs for transitioning a signal trace between inner copper layers of a multilayer PCB

The test vehicle is a multilayer circuit and is a stripline configuration. The circuit is designed to show the impact of transitioning the signal trace from one copper layer to another, while maintaining the stripline structure. These signal transitions are less problematic at lower microwave frequencies (< 2 GHz) however at higher frequencies these transitions can cause reflections, poor return loss, impedance ringing and degraded insertion loss. This study will demonstrate with measured results, several different PTH via designs used to transition a signal trace to different copper layers with improved bandwidth and signal integrity.

Presenter Bio:

John Coonrod is a Technical Marketing Manager for Rogers Corporation, Advanced Connectivity Solutions. John has been involved with the Printed Circuit Board industry for over 28 years. The initial 11 years was spent in the Flexible Printed Circuit Board industry responsible for circuit design, applications, processing and materials engineering. Following this experience, John supported the High Frequency Rigid Printed Circuit Board materials made by Rogers in regards to circuit fabrication, application support and electrical characterization studies of these materials. John is the Vice Chair on the IPC D24C High Frequency Task Group and holds a degree from Arizona State University in Bachelor of Science, Electrical Engineering.