PCB Antennas April 25, 2008
From time to time, I get questions about antennas (particularly PCB antennas), so I figured I would at least make a small “stub” of a post to serve as a place to discuss the topic.
For example, Sia writes “How can we find the impedance?”
For antenna impedance (and other antenna properties), there is no one simple answer. The impedance of an antenna varies with the geometry of the antenna, frequency used, and proximity to ground planes and other nearby conductive objects. That is what makes them fun to learn about for some people and evil black magic to others.
The best thing I can recommend is to do a Google search on “antenna impedance” and become familiar with the various standard geometry antennas that you will find (e.g. quarter wave, half wave dipole, folded dipole, yagi, loop, etc.). Each type has specific impedance, gain, directionality, and other properties, so you can make some design trade-offs. Since you asked about impedance, you may also want to Google “RF impedance matching”.
The actual math behind antennas is pretty esoteric (3-D partial differential equations) and is usually taught in the 3rd or 4th year of electrical engineering programs, and even then, only if RF is selected as the area of concentration. It is worth noting that specialized software is often used to solve these kinds of problems.
Since this is a stub article, at this point I will open the floor to reader comments!
- Posted in : Electrical Engineering, PCB
- Author : Brad
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