This two-port dual circularly polarized X-band feed horn antenna (both LHCP and RHCP) is designed by the Czech amateur radio operator Zdenek (Zdeno) Samek OK1DFC, with a septum feed. The sample tested here at 10.368 GHz was built by the German amateur radio operator Hubert Tiedmann DJ3FI. This antenna was "patterned" in the anechoic chamber www.RTCE.com of Glenn Robb KS4VA, on behalf of Paul Wade W1GHz. The software used to plot the animated measured gain data is 4NEC2 (version 5.8.8 or higher), is written by the Dutch ham Arie Voors, and is available at ...
http://home.ict.nl/~arivoors/
Analysis: Absolute gain was measured at 57 different frequencies from 8 to 12 GHz (X-Band) in 360 "directions", as two polar cuts in the XZ and XY planes, at 2 degree resolution. Peak on-axis gain was +8.0 dBi. The 3dB-beam-width was 99 degrees in both planes.
Additionally, 3D gain data was taken at the same 57 frequencies in 2700 directions (5 degree resolution spherical co-ordinates). This allows both 3D visualization of the gain pattern, and the spherical integration of total isotropic gain (TIG) and calculation of radiation efficiency. At 10.368 GHz radiation efficiency was essentially 100%, and efficiency was within 1dB of 100% over the range of 9 to 11.5 GHz.
Also, axial ratio was measured with a Phi axis roll, and is graphed as a function of frequency for both ports. At 10.368 GHz, the axial ratio for Port A is 4.1 dB, and is 4.4 dB for Port B.
Full spreadsheet data and photographs are available at...
http://www.rtce.com/example_report_10.htm
