High power ceramic RF filters/combiners

Jun 06, 2018 4 Replies
M

Can someone point me in the right direction to have a custom RF filter designed? Needs to be small, and high power. 20-watts (minimum), and covering several communication bands (we'll choose per design if need be), 600 MHz up to 3.5 GHz.



Maybe up to 5-bands (in parallel, with port-to-port isolation, etc) per design.



I have the 20-watt ceramics. The trick is to get all the combining/loading right without burning stuff up. And I need to keep the corresponding receiver noise floors down.



Looking to farm this out.



Thanks


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M

You have ceramic filters that can handle 20 Watts?

Prey tell.

m
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U

At such power levels, one would think about helical filters.

Are there any significant power levels in the stop band ?

Is it OK to just have some severe impedance mismatch in the stop band and simply reflect the unwanted power back or is some diplexer style construction needed to filter out the stop band to one port an dissipate in a power resistor ?

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J

I'm guessing he means ceramic capacitors rather than filters. :-)

Johnny B Good
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J

Possibly a superconducting filter made from YBCO (yttrium barium copper oxide), which is a ceramic. The losses are very low, but I'm not sure if the cryo cooling system can handle 20 watts. I couldn't find anything at cellular frequencies, but at 9.5GHz, this 3 pole BPF has a loss of 0.08 dB at

77 K and less than 0.04 dB below 60 K. 0.1dB is 2.28% power loss. At 20 watts in, that's 0.46 watts of heat. If the cryo fridge can handle 0.46 watts of internal heating, it should work.

Disclaimer: I'm guessing and have no idea if this is what the OP really wants.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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