Example 6: LHCP Omnidirectional FPV Antenna

This Example Test Report features a small LHCP omnidirectional antenna designed by the talented Maarten Baert. It is a sophisticatedly simple design with three PCBs on a semi-rigid coax and an SMA connector. This inexpensive antenna was designed for the 5.8 GHz WiFi market, targeting FPV (first person view or remote person view) drone control transceivers. When fitted with a plastic cover, these antennas earn the nickname “lollipop antennas” and are popular among hobbyist RC drone racers.

This antenna performs very well, and has essentially 0 dBi gain in the intended sideways directions, where its axial ratio is around 2 dB. Radiation is verified as LHCP with a cross-polarization rejection ratio (in the sideways directions) of close to 20 dB. Realized radiation efficiency is 78% at 5.8 GHz, impressive for an C band antenna made with inexpensive FR4 PCB material. 

The linked test report spreadsheet details full measured Gain Magnitude, LHCP, RHCP, and axial ratio data over the entire 3D sphere (approximately 400 physical test directions and 101 test frequencies). 

Excel data files are available for download here.

The 3D plotfile can be downloaded here. You can render rotatable and scalable 3D plots at any of the 101 test frequencies on your desktop with this free downloadable software.