Right Angled Tracks (90 Degree Traces) – Are they Good or Evil?

There has been many rumors and myths flying around about right angled tracks on PCB being bad for PCB. You may hear people say that they are bad for EMI (Electromagnetic Interference) and reflections.

90 Degree traces pcb 45
90 Degree traces pcb 45

According to Studies UltraCAD Design, Inc, they compared and tested both 45 degree and 90 degree corners in microstrip traces [1]. The 90 degree corner didn’t show an increase in radiated emissions. All  trace geometries produced radiated emissions that were 35-50 dB below the emissions of a 3-cm long monopole antenna and only slightly above those from a straight trace with no corners.

Another paper by M.I Montrose confirms the experiments by UltraCAD, by testing the trace geometries in both the Time and Frequency domain for Signal Integrity as well as EMC compliance respectively [2].

Therefore there is absolutely design laws that say that you should not use right angled tracks. Here are my personal reasons for not using 90 degree traces or tracks

  1. They look cleaner on the PCB,
  2. The 45 degree trace geometry offers a shorter path between components,
  3. Its common practice.

So with that being said, I will leave it up to you to decide what trace geometries you would prefer for PCB design.

By Ritesh Kanjee

[1] Doug Brooks, "The Final Turn" UltraCAD Design Inc, URL: http://www.ultracad.com/articles/90deg.pdf
[2] M. I. Montrose, "Time and frequency domain analysis for right angle corners on printed circuit board traces,"Electromagnetic Compatibility, 1998. 1998 IEEE International Symposium on, Denver, CO, 1998, pp. 551-556 vol.1. doi: 10.1109/ISEMC.1998.750154 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=750154&isnumber=16215

Ritesh Kanjee has over 7 years in Printed Circuit Board (PCB) design as well in image processing and embedded control. He completed his Masters Degree in Electronic engineering and published a paper for IEEE called Vision-based adaptive Cruise control using Pattern matching (on Google Scholar). His work was implemented in LabVIEW. He works as an Embedded Electronic Engineer in defence research. He has experience in FPGA design with programming in both VHDL and Verilog.