strip width calculation

There are many tools and applets out there making use of (W/d) ratios to calculate the specific microstrip width for a specified characteristic impedance. All these formulas take into acount a relatively big ground plane. What if the ground plane was tapered and not considered to be big enough. Are there any formulas that calculate the width of the line for a specific impedance?

The application of this is a microstrip tapered balun.

I would use those tool as a initial value for full wave analysis. I think that is the best way for finite ground plane.

But at the end of a balun, the ground plane strip width (bottom conductor) is as wide as the upper conductor. How does one account for these width given a desired characteristic impedance?

I suggest you use the ADS to simulate that will be better!

Hi,

This might help.

flyhigh

It is a common problem. The best is to start with schematic simulation such as ADS or AWR or others. Next jump to an EM simulation. I like the Momentum of ADS, but there are others. In order to simulate an finit ground you have to define correctly the RF ports.

D.J

Do anybody know how to know the actual size of a triangle sierpinski fractal antenna?
Does it related to the operational frequency or anythings else?

Hope to get reply from u all, thanks,

My e-mail ... djtommy_bigtank@yahoo.com

when Wu/Wb>11(Wu|:upper strip width,Wb:bottom strip width),we can consider the bottom strip as the infinite-width!if you want detail,you can
read "Microstrip Transmission Line With Finite-Width Dielectric and Ground Plane" by CHARLES E.SMITH and RAY-SUN CHANG

Do anybody know the way to calculate the characteristic impedance of a sierpinski fractal antenna(triangle)?

And if i'm doing line-edge feed, how to calculate the dimension of the line?

have you any papers or text about Merchand Balun? please upload it!