NEC-LIST: coax line with strip center conductor ?

Dear Jos,
 
I found two more expressions for the impedance of coax lines with
center strip :
 
1.) Z line = (15*pi^2)/{ln[4/(1-b/d)]} for d/b ~ 1
 
              where d = inside diameter of coax
                    b = width of center strip
                    
     this is for eps r = 0 ( eps 0 = eps r )

     if eps r must be included, I believe the first term must
     be divided by the sqrt of eps r
 
2.) Z line = (60/sqrt eps r)* ln(2*d/b) for d/b > 2
 
     eps r included
 
Regards,
 
Max Schmitt
Cons.Eng.
Received on Mon May 01 2000 - 04:13:35 EDT