// Microstrip Calculators 
// Copyright (c) 2008, CEPD Inc.
// http://www.cepd.com


function eff_w(w,t,h,eps) {
var T1,wef;
		
	T1= 4*Math.E/Math.sqrt(Math.pow(t/h,2) + Math.pow(Math.PI*(w/t+1.1),-2));
	wef = w+t*(1+1/eps)/2/Math.PI*Math.log(T1);
	return wef;
}

function CalcZ(form) {

	var w,h,t,eps,weff,Z;
	var T1,T2;

	w = parseFloat(form.w.value);
	h = parseFloat(form.h.value);
	t = parseFloat(form.t.value);
	eps = parseFloat(form.eps.value);
	weff = eff_w(w,t,h,eps);
	T1=(56+32/eps)*h/weff/11;
	T2=T1+Math.sqrt(Math.pow(T1,2)+Math.PI*Math.PI*(1+1/eps)/2);
	Z=42.4/Math.sqrt(1+eps)*Math.log(1+(4*h/weff*T2));
	form.Z.value=Z.toFixed(2);
 }
 
 function CalcDiffZ(form) {
	var h,s,Zo,Zd;
	
	h = parseFloat(form.hd.value);
	s = parseFloat(form.s.value);
	Zo= parseFloat(form.Zo.value);
	Zd=2*Zo*(1-0.48*Math.pow(Math.E,(-0.96*s/h)) );
	form.Zd.value= Zd.toFixed(2);
}