how do I calculate micro-strip?

[gribi20]

hi , I'm going to use RO4003C substrate to design coupler 180 deg , that work from 2 to 4 GHz .I got the specification from the internet of the substrate from Rogers Corporation , how do I calculate the dimension of w/d and how to get effective dielectric constant ? to let me able to finish my design .notes plz im beginner

 

[DDavid]

in what cad u are working?

 

[gribi20]

well, so far I prefer to using manual calculation but I can use linecalc in ADS

 

[DDavid]

So if u have ADS u can do it with linecalc...

 

[gribi20]

well, I do have this parameters but I think they are not enough to do the rest of calculation

 

[DDavid]

u have all u need

first please define H of the wanted PCB
second T
take from table Er and Tang delta
dont forget to define u freq
and that's it
go to Linecalc...

 

[gribi20]

Thatz the question , how to calculate H and T ?

 

[DDavid]

U don't calculate
u take what from datasheet, Rogers give u

below to the table that u attached u can find
standard thickness that H
and standard copper cladding it T

 

[gribi20]

welll , thank you , but which one should I choose ? and what about Z0?

 

[volker_muehlhaus]

but which one should I choose ?

This is an engineering decision.

Thick substrate --> wider lines, wider gaps
Thin substrate --> narrower lines, narrow gaps

 

[DDavid]

if u want to design coupler for 2 - 4G
i would start with 32mil substrate 1oz T (1oz if u not going to work with high power signals),
height of the pcb can and will enflunce on your design (like volker_muehlhaus told it will define your line w), but once again 32mil it good start)
Zo depend on your system usually it 50 Ohm.

 

[OldRFguy]

Rogers Corporation have an excellent tool on their website for just this purpose, check it out:

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