FR4 or RT substrates good for power divider fabrication

[shilpa.k]

what is the best substrate to fabricate a wilkinson power divider- FR4 or RT substartes like RT 5880/5870?

 

[BigBoss]

Rogers is of course better but more expensive.If your operating frequency is not too high ( up to 1-2GHz), FR-4 can also be used.
But Rogers has always lower loss than FR-4..

 

[volker@muehlhaus]

It depends what "better" means for you.

FR4 has higher permittivity, so the divider will be smaller than the RT5880 version.
RT5880 has lower loss, but also low permittivity, so the divider will be larger than the FR4 version.

RT5880 is teflon based - special manufacturing required - expensive.
There are other substrates that have high permittivity and low loss and cost effective manufacturing, for example Rogers RO4360G2 (er=6.15, tand=0.003)

 

[Tomsin yin]

hi shilpa.k
currently am designing a 4-way power divider with its frequency range 2~3Ghz.firstly i used FR-4(Er=4.4,H=1.6mm),but i can not get correct index,S21 is too weak,since the TanD is about 0.02 for FR4.its loss is very big.if ur work frequency is more rhan 3Ghz,u should not use FR4,beacause its Er will change(is not 4.4)

 

[shilpa.k]

Thank u
My wilkinson power dividers are for 1.8&2.6 GHz..i hve designed them using RT5880... But m unavailable to obtain d substrate now...so was thinking of variation if any

 

[Tomsin yin]

am sorry that what is the meaning of "d"?

 

[ge]

Have you looked at Ro4350? Er is somewhat close to FR4. Cost more than FR4 but much less than 5880. 4350 is very common in USA.