Sci-Wcalc: coax

Sci-Wcalc: coax_syn

coax_syn - Coaxial transmission line synthesis

SYNOPSIS

[a_out, b_out, c_out, er_out, len] = coax_syn(a, b, c, t, rho_a, rho_b, er, tand, len, f, flag)

PARAMETERS

INPUT PARAMETERS

a : radius of inner conductor (meters)
b : inner radius of outer conductor (meters)
c : offset of the inner conductor from the center (meters)
t : thickness of shield (meters)
rho_a : resistivity of inner conductor (ohms/meter)
rho_b : resistivity of outer conductor (ohms/meter)
er : relative permitivitty of dielectric
tand : loss tangent of dielectric
len : physical length of line (meters)
f : operating frequency (Hertz)
flag : indicates which parameters should be optimized
- flag=0 : synthesize a
- flag=1 : synthesize b
- flag=2 : synthesize c
- flag=3 : synthesize er

OUTPUT VALUES

a_out : synthesized radius of inner conductor (meters)
b_out : synthesized inner radius of outer conductor (meters)
c_out : synthesized offset of the inner conductor from the center (meters)
er_out : synthesized relative permitivitty of dielectric
len : synthesized physical length of line (meters)

DESCRIPTION

Function to synthesize the physical parameters of a coaxial transmission line to achieve a given set of electrical characteristics.

EXAMPLE

 // mils to meters conversion factor
sf=25.4e-6;
 // desired characteristic impedance
z0=75.0;
 // desired electrical length (degrees)
elen=90.0;
 // radius of inner conductor
a=10.0*sf;
 // inner radius of outer conductor
b=100.0*sf;
 // offset of inner conductor
c=0*sf;
 // thickness of outer conductor
t=5.0*sf;
 // resistivity of inner conductor
rho_a=3.5e-8;
 // resistivity of outer conductor
rho_b=rho_a;
 // relative permitivitty of dielectric
er=9.5;
 // dielectric loss tangent
tand=0.01;
 // 100 MHz operation
f=100e6;
 // synthesize b
flag=1;
[a,b,c,er,len] = ...
   coax_syn(z0,elen,a,b,c,t,rho_a,rho_b,er,tand,f,flag);
disp(sprintf('z0   = %g Ohms',z0));
disp(sprintf('elen = %g degrees',elen));
disp(sprintf('a    = %g m',a));
disp(sprintf('b    = %g m',b));
disp(sprintf('c    = %g m',c));
disp(sprintf('er   = %g ',er));
disp(sprintf('len  = %g m',len));