groundhog1
Electrical
- May 4, 2003
- 43
I built up a plain rectangular patch antenna with the probe feed on the diagonal to set up circular polarization.
Using my network analyzer, and putting itentical antennas on both ports, everything looks fine to me. I can rotate the antenna and at center freq, the insertion loss between the antennas (ant gain and space loss) looks fine and predictable.
The gain is slightly lower than I expect at around 1 dbi.
Then I sent one of the antennas to my buddy in another state. He has an antenna chamber. I also sent him with the antenna, a cavity backed wideband spiral RHCP antenna to use as a pickup.
He sends back data that doesn't make sense.
When he uses his horn pickup, and takes two cuts 90 degrees apart, the pattern looks ok. But when he uses the RHCP spiral as a pickup, the pattern is weird and very lossy. He also has a LHCP antenna and used that too to plot the opposite polarization. His plots of RHCP and LHCP gain are about the same in magnitude.
Any hints as to what could be causing this?
thanks,
gh