This page is a list of embedded animations and video which is part of the “Absolute Beginner’s Guide to RF and Microwave PCB Design”, a full-day design workshop presented at the PCBWest conference, 2020, and as a half-day workshop in 2019.
Attendees viewing this year’s presentation online will need to link back to this page to witness the interactive parts of the presentation, because the presentation system employed by UP Media for the conference is not capable of supporting the animations within the presentation slide deck.
Just as a test – here’s the first embedded video from my YouTube channel:
If you can play that video, great! You’re all set. Let’s go…
Electromagnetics Basics Recap
Figure 1: EM Basics – radiating dipole
Figure 2: Perpendicularity of E and M fields
Another more frequent way of visualizing a traveling plane-wave through space is the orthogonal E and M traveling waves. In this case the wave is representing a SIN wave E field and M field of particular amplitude but with modulation (ie. carrying data) the waves would no longer be simple sinewaves.
Figure 3: Sinewave EM propagation
Figure 4: Charge Carriers (electrons/holes) moving in a conductor. I HIGHLY recommend watching those ancient Canadian Air Force training videos on Doug’s channel. They are one of the best resources I’ve seen to illustrate the essential physics in a totally intuitive way. Yet to be topped by 3B1B or any others IMHO.
Figure 5: Demonstrating “CURL” in a 2D animated vector field
Figure 6: Putting it all together, you can visualize this as ‘plane wave’ propagation.
Figure 7: MEEP simulation (FDTD) of a plane wave from a bar source propagating laterally through two different dielectrics – εr =1 and εr = 4.8. You can clearly see the slower velocity of propagation which leads to shorter wavelength in the material.
Figure 7a: Current and Inductance
Figure 8: An “incident” wave represented as a sinewave voltage moving down a matched transmission line and load – all energy is delivered to the load in the ideal scenario.
Figure 9: A digital pulse traveling down a line that encounters an impedance anomaly will cause all sorts of reflections. In this case, the dotted line is the distance at which the impedance suddenly becomes higher.
Figure 10: If the load on the end of a transmission line is not “matched” to the system impedance, some of the energy must be reflected back up the line.
Figure 11: A line with an short circuit at the end will produce this ‘standing wave’, with a node 1/2 wavelength back from the end. Note the voltage is 2x the incident – thus if you transmit from a radio amplifier into no load you are likely to blow up the output stage.
Figure 12: Similar to Figure 11, only this time we are sending into an open circuit. This time the first voltage node is 1/4 wavelength back from the end and the end of the line exhibits the voltage peak 2x the incident.
Figure 13: When the load at the end of the line is reactive (ie. capacitive or inductive) the peaks and nodes are some fraction of a wavelength back. The voltage of the peak and the node and it’s location will tell us how well the match is, and whether it’s inductive or capacitive. This ratio of peak to valley is the “votlage standing wave ratio” or VSWR, or simply SWR. VSWR value =1 for a perfectly tuned (matched) system.