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50/30 ohm coax adapter

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mhughes

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My system requires a 50 ohm input feed to a 30 ohm load. I am trying to design a coax adapter with the lowest possible mismatch...does anyone have any recommendations? Freq is 100MHz to 11GHz. Any help is appreciated.

Thanks!
Mike
 

"Minimum Loss Pad/Attenuator" may be a solution within this Bandwidth.
 

Minimum loss means 6.5 dB in this case. Is it acceptable for the application?
 

Thank you..I was thinking a 1/4 transformer at first, but with the bandwidth I don’t know it will work. The min loss pad could be the only solution...6.5dB is ok. Any idea how to proceed with this? This is always in a coax structure. Thanks
 

Thank you..I was thinking a 1/4 transformer at first, but with the bandwidth I don’t know it will work. The min loss pad could be the only solution...6.5dB is ok. Any idea how to proceed with this? This is always in a coax structure. Thanks

You can calculate the resistance values here..
https://home.sandiego.edu/~ekim/e194rfs01/minl_atten/minlosatten.html
Then you should find a tubular mechanical part that is convenient for your coaxial connectors ( N-Type, SMA etc) After that, prepare a PCB that will fit into this mechanical tubular structure and choose the resistances in according with your Power Level and attenuation accuracy.This is hand-made solution.
There may be-I don't know- ready to use solutions from different manufacturers.
 

Thank you BB! The pcb is an option...as a handmade solution.
 

100M to 11G

That is a big bandwidth. You can forget about a magnetic transformer, or quarterwave section.

You will need a broadband matching network.

But seriously, why do you care? That is a return loss of 12 dB. You can not take that sort of mismatch? If not, add a 2 dB attenuator pad in front of it, and the total return loss will now be 16 dB, and so on.
 

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