So, I came across, where antennas are being tested in a building ( a plant), where all sorts of big equipment are around and of course the ceiling. lot of multipath which can affect the performance of an antenna. What is the cheapest way if I can get any suggestions to test the antennas, if we do not want to go outside and does not have a budget for a big anechoic chamber? Any suggestions are going for helpful.
Thanks
Meenakshi Kohli you can use a plane wave test source in a room with the EM wave pointing towards the window side (open wall). Use low power at the test source. Keep the AUT in between the test source and window at far-field distance. This should work for small antennas whose dimensions are small compared to window opening. If the window can be opened, you can open it for tests.
Build an anechoic chamber approximation yourself. Everyone does exactly that, except it is considered a bad taste and not correct and... there are countless arguments against that, finishing with "FCC strongly forbids"... but believe me, everyone does it at home. Just buy a bunch of pyramidal absorbers in your band for covering the largest space available for your quasi-chamber. I recommend some plate foam carbon absorber behind these cones as a basis, and carbonized paper-fan absorbers in the corners. Do not screen the absorbers at the back with metal sheets, how strict rules require. It is not good for EMC, outside the "chamber", but improves the performance since the passed wave will scatter away outside, reducing direct reflection. Buy an optical stepped rotation stage, compatible controller with pricision meter function, a National instruments GPIB controller (if it is GPIB and not Ethernet... try getting LabView compatible components which means better general support). Get a lot of polysterol foam, wooden bars, plastic screws for building stands, and two carbon tubes possibly with carbon tripod for antenna and DUT masts.
Then you can connect RF to a network/spectrum analyzer, and and everything to your PC with Excell installed. Then make a script in excell. I recommend reading network analyzer data in binary buffer mode, because it is 100 times faster than ASCII, and makes quick full-band synchronous scanning possible.
We can provide the testing in our lab ELARC with minimum costing.
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