All About Circular Polarization and the Axial Ratio (Download)
When using antennas for communication, it’s important to get the polarization right between the transmitter and receiver. Most engineers are familiar with horizontal and vertical polarization and understand that it’s best if the transmit and receive antennas have the same polarization. In fact, if the transmitter is using a vertically polarized antenna while the receiver uses a horizontally polarized antenna, it’s unlikely that a communication link can be established at all.
What some engineers may not know is that in addition to horizontal and vertical polarizations, there’s a technique called circular polarization. This article explains what that is, how it behaves, and how it can be measured.