Hi, everyone. I have a question about the RF test cable. I am going to make a prototype of an antenna. The test device is the network analyzer with SMA connector.
I am wondering what type (model) of the RF test cable I can use.
The prefer cable should have one end with SMA connector, and the other end with bald end, which means that the inner conductor of cable can be extended out to be soldered on the antenna feed, and the outer conductor can be soldered to the PCB ground.
It depends on many things, but mainly on the frequency.
If the frequency is lower than 1 GHz you can use a RG142 cable, after 1 GHz use a semirigid cable as UT141.
Anyway to make this for frequencies higher than 1 GHz depends on many other parameters, as the exposed lenght, soldering, flux, etc.
Hi, Mandi. My project is working under 3GHz. And the cable should be easy to bend. The inner conductor exposed length is not quite long. I just want to solder the inner conductor to the feed of the antenna. So do you have any recommendation of the cables? Thanks very much for your help.
common RG, double braided coax cables may be used up to 5 GHz.
Phase and level stability are not excellent, but often good enough.
For istance, RG142 (PTFE) or RG223 (PE) are easy to connect, cheap, and lightweight solution.
Also their velocity is well kown so You can extend the VNA port along the cable.
I'm pretty sure a TRL calibration could be done here out to the end of your feed cable. You could use both methods. You can add in delay directly to the network analyzer to rotate the impedance into the proper place, which would negate the affects of your feed cable.
I'm a little rusty and haven't done this for 15 years, so I may have made a mistake.
you can use any cable you have as long as you calibrate you VNA with it.
I think the best cable is RG142, but you can use also RG55, if the cable needed is short use a semi-rigid.
Jayleung, I don't know if you're a student or a business or where you live, but as a student you could likely get a vendor/company to donate your cable requirements and get connectors. They may even possibly install them too. Installation can be a very strong learning experience as well!
Hi, Samurai. Yes, I am a student in US. Actually I have installed SMA connectors to the cable before following my fellows in our lab.
However, since right now that guy have graduated, I don't know where he ordered that kind of cable.
Actually the cable I used before has no copper braid but solid as outside surrounding conductor. And I just need to use a small knife to cut a portion of outer shield copper and isolator out and solder the SMA connector on it.
And since all the RG type cable are braid type, I really don't know what kind of cable it is.
If someone is doing the antenna prototype before, please help.
Well, now your an engineer. A big part of it is hunting parts. It takes a lot of time...... Google cables. If you want semi rigid, then there are companies out there. The rep will help you get what you want. I bet if you called the local Agilent representative, they'd tell you who to call or give you cable. Ask a professor for a local rep! Go to rfglobalnet or rfcafe.
Jayleung, thank you for the "helped" button pushes, I can't seem to be able to find that button when I want to push it for people. Can you tell me where it is located? Is it the donations button?
Thanks
Added after 3 hours 9 minutes:
found it. I didn't create the posts, so I couldn't see the button.
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