What are the limits for passing RF signal through a slip ring?
I do not know the reasons, but although there are slip rings supporting interfaces as 1 Gigabit Ethernet or even 10 Gigabit, slip rings are not used for passing RF.
Anyone knows the reason?
Slip rings, Rotary Joints, Ring, Transmission system, Systems, Schleifring, Joint, Electrical slip
RF rotary joints have to be compact and shielded, but they are available, and the above website is just one of several examples ..
IanP
They make circular waveguide "slip rings" that can pass pretty much any frequency (over a reasonable bandwidth) that you want. They also make quasioptical microwave "slip rings". They just do not have any contacting parts!
If you really want to make a physical slip ring, you have to realize that it will look like a circular resonator, and only work at a very limited bandwidth. Also, the position along the slip ring that you contact to will leave reactive loading that varies as position is varied. If they make such things for gigabit logic, they must be small radius, and must have some way to suppress the time domain ringing that they will invariably have.
I do not intend to make a slip ring. I will buy it.
I have been looking at several manufactures websites as Moog, Shleifring, Diammond Antenna, but I did not succed in finding the rationale for passing signals by the expensive Rotary Joint or by the cheaper Slip Ring.
biff44, which is the origin of the time domain ringing you mention? Is it a modulation due to the joint rpms?
MDL - Microwave Development Laboratories - The World Leader in Waveguide Components
Thank you biff44. Do you know MDL has also slip rings? I did not found them in their catalog. Anyway I will contact them.
Here is another source: Cobham has been absorbing various microwave companies and now includes Kevlin a long time rotary joint supplier. I took a quick liin at their site but it looks that a bit of digging will be needed to get to the right part. I suspect that your motivation to wade through the site is higher than mine. Have faith, Kevlin is still around, only a bit hidden.
As a general comment, if you are below 2 GHz you might be able to get away with using a slip ring channel. Above that good luck.
Regards,
Azulykit