selection of substrate in microstrip design

[abhijitrc]

yes, thermal expansion is a big issue. But the real fact is that different expansion can cause grounding issue. That is fatal.

Dear sir,

Any other point which makes alumina more attractive than Rt-Duroid!!!

 

[volker_muehlhaus]

what is the advantage of using alumina substrate over other soft substrate?

The soft substrate is mechanically soft, so it is usually attached to some metal back for mechanical stability.

 

[abhijitrc]

I have a doubt in a typical application oriented issue:

1. I have been given the option of two substrate a. RT-duriod( 10.8 relative permitivity), b. alumina (9.8 permitivity), i have to design LNAs , Active multplier circuits etc at 17 GHz for receiver front end, once the package will be realized it has to under go temperature cycle( -30 c to +60 c). Which substrate will be best for me and which will cater all the problems.

 

[noor_]

beside the expensive of substrate materials
there is other disadvantage for using a thicker substrate,a thicker on will cause the excitation of surface waves

 

[Pcb Vision]

Dear guys,

Our factory can help you fabricate the PCB with Rogers substrates with good quality, and also, the technology for pressing FR-4 together with Rogers are in mature.
if you would like to get more, don't hesitate to make your comments .