Antennas: power loss on polarization mismatch

Most people in RC hobby knows that receiver and transmitter antennas should match polarization. But what would happen if there was a mismatch? For example when transmitter uses linear vertical and receiver circular left hand? There would be a loss of power, attenuation. How much? Look at table below. Remember: -3dBi means half of power is lost during polarization change and you need +6dBi power (4 times more) to increase range by factor of two.

 

Vertical Horizontal LHCP RHCP
Vertcal 0dBi -20dBi -3dBi -3dBi
Horizontal -20dBi 0dBi -3dBi -3dBi
LHCP -3dBi -3dBi 0dBi -20dBi
LHCP -3dBi -3dBi -20dBi 0dBi
  • -20dBi is practical value. In theory, all power should be lost during this conversion. But we are living in not perfect world and always some power will go though
  • Vertical – Linear Vertical Polarization
  • Horizontal – Linear Horizontal Polarization
  • LHCP – Left Hand Circular Polarized
  • RHCP – Right Hand Circular Polarized

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