Quadrifilar Helix Antenna is omnidirectional circularly polarized antenna. It's ability to receive or transmit a tight beam of circularly polarized radiation while minimizing unwanted radiation perfect fits especially for satellite communication. This 3D model helps to achieve correct shape of antenna segments which has crucial effect for correct circular polarization.
Antenna is made from 2 pcs of 0.8mm silver plated copper wire, with total length 357 mm and 339.4 mm.
Antenna feed
RG174 coaxial cable with SMA connector
Antenna spectral characteristic
Calculated in: http://jcoppens.com/ant/qfh/calc.en.php
Warning. 3D model add parasitic capacity to antenna which moves resonant frequency. This was corrected by calculating antenna for higher frequeny (913 MHz). Changing any parameter must be verified by measurement. https://github.com/cernohorsky/QFH-Antenna-868MHz/blob/master/pictures/QFH-Antenna-868MHz-Param.jpg
Original 3D model: http://www.thingiverse.com/thing:634205