Sci-Wcalc: ic_microstrip

Sci-Wcalc: ic_microstrip_syn

ic_microstrip_syn - Integrated circuit microstrip transmission line synthesis

SYNOPSIS

[w_out, h_out, tox_out, l_out] = ic_microstrip_syn(z0, w, h, l, tmet, rho, rough, er, tand, f, flag)

PARAMETERS

INPUT PARAMETERS

z0 : desired characteristic impedance (Ohms)
w : width of ic_microstrip line (meters)
h : substrate thickness (meters)
l : lentgh of ic_microstrip line (meters)
tmet : metal thickness (meters)
rho : resistivity of wire (relative to copper)
rough : conductor surface roughness (meters-rms)
er : substrate relative permitivitty
tand : substrate loss tangent
f : synthesis frequency (Hz)
flag : indicates which parameters should be optimized
- flag=1 : synthesize the metal width
- flag=1 : synthesize the substrate thickness
- flag=2 : synthesize the oxide thickness

OUTPUT VALUES

w_out : calculated metal width
h_out : calculated substrate thickness
tox_out : calculated oxide thickness
l_out : calculated metal length

DESCRIPTION

Function to synthesize the physical dimenstions of a single ic_microstrip transmission line to achieve a desired characteristic impedance and electrical length. The desired characteristic impedance and some of the physical dimensions of the ic_microstrip line are given as inputs and the remaining dimensions are calculated. The model accounts for dispersion (frequency dependent propagation velocity).


                 |<--W-->|
                  _______    
                 | metal | <- tmet,rho,rough
    ----------------------------------------------
   {**************  Oxide (tox,eox) **************
    ----------------------------------------------
   (  substrate                          /|\     (
    )   es,sigmas                     H   |       )
   (                                     \|/     (
    ----------------------------------------------
    XXXXXXXXXXXXXXXXXX ground XXXXXXXXXXXXXXXXXXXX

EXAMPLE

 // desired impedance
z0=75;
 // desired electrical length (degrees)
elen=90;
 // micron to meters conversion factor
sf=1.0e-6;
 // width 
w=160e-6;
 // length
l=1000e-6;
 // oxide thickness
tox=1.0e-6;
 // oxide relative dielectric constant
eox=4.0;
 // substrate thickness
h=250e-6;
 // substrate relative dielectric constant
es=11.8;
 // substrate conductivity (1/(ohm-m))
sigmas=10;
 // metal thickness
tmet=1.6e-6;
 // metal resitivity (ohm-m)
rho=3e-8;
 // metal surface roughness
rough=0;
 // frequency
f=2.4e9;
 // synthesize width
flag=0;
[w_out,h_out,tox_out,l_out] = ...
    ic_microstrip_syn(z0,elen,w,l,tox,eox,h,es,sigmas,tmet,rho,rough,f,flag);
disp(sprintf('w   = %8.3g um', w_out*1e6));
disp(sprintf('h   = %8.3g um', h_out*1e6));
disp(sprintf('tox = %8.3g um', tox_out*1e6));
disp(sprintf('l   = %8.3g um', l_out*1e6));