Building a RF free space measurement and a waveguide setup

Thread Starter

olorenzen

Joined Nov 1, 2023
2
Hello!
I am doing a internship at the RF department of an university right now and got the following task today. I have to research on how to build two measurement setups for microwave measurements or respectively material measurements. The first setup should be a free space measurement system with two horn antennas for 1 to roughly 26 GHz with the option to change the angle of the antennas. I saw that there are systems using an arch for such an angle change and other use a table with a rotational axis for one of the antennas. The other setup should be a waveguide measurement setup for a bandwidth up to 20 GHz. When it comes to the budget I got the guideline that the free space measurement setup should cost not much more than 100k $.
I could really use some help/expertise for this task. Especially on which specific horn antennas I could use, which cables are suitable for this kind of setups, any tips on the construction of those kind of archs or tables for antenna rotation, ... . I would be very thankful for any kind of shared experience when it comes to building this kind of setups for precise measurements for research purposes.
(I know that there are companies that sell these kind of setups as a whole, but their prices are so high that it seems to be the more rational choice to build it yourself)
 

Janis59

Joined Aug 21, 2017
1,821
RE:""I know that there are companies that sell these kind of setups as a whole, but their prices are so high"" Absolutely understand You. BUT, ought to sniff the construction near as possible, probably is worth to visit personally and sniff what the producers are the details used in it. Just, You have to understand to the smallest detail how it must be built.

The one thing is rotation table. I would use the bakkelite plywood where with simplest electric hand overgrinder may be proceeded a round channel for balls. Two such plates and bunch of balls is damn effective, cheap and gives up to the 0.1 mm precisity. If not enoygh, make it on basis of duraluminium with the same tool (her how it looks www.kursi.lv/lv/virsfreze-bosch-pof-1200-ae). Simply add the rotational axis to those two needles and voila!

Then antenna is thing to make Yourself, hope the 3d encarver is well known tech and how to play with 3d-Mach.
The wavequides including the launcher, circulator and 3-knob matcher must be bought in specific USA firms for about 4 KEur. Firm names shall find by the wavequide name, Your second post I specified what You need.

Magsells.co.uk, dolphmw.com, indiamart, alibaba, markommicrowaves.com, ibf-electronic.de, pasternack.com, enerzi.co, vectortele.com, dolphmicrowave.com, and many more.
 
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Janis59

Joined Aug 21, 2017
1,821
About the FreeSpace. When I designed the Cleanroom at our lab, the cellar had very dirty environment thus I choiced to glue all walls with PE film, over which mount the AISI-306 plane steel, over what is going meander-shaped second AISI layer plates. Those tunnels between first and second layer is used to manage air re-circulation via the special filters by stainless radial fans. Large was my surprise when I noticed that involuntary I have obtained RF free space, yet not complete, but near to entrance doors are about -180 dB and deeper in room about -180 dB whilst outside -90 dB. Only defect is nearby staying 50 Hz mains substation transformer giving about 100 uT in near it wall and about 30 uT in far wall. But normally 50 Hz is so far from RF that isn`t the irritating at all. So... if interested, our universities may make a friending plan (on the concourse basis even it may be paid by EU), and use of freespace room will be free of charge in such case.
Which city You are from? I am from N56.94830136499251, E24.106349840420965
 
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