Coaxial Rod Array in Tube Section

Home

        Goto:   Inductance      Output Format        Notes

Definition:                           

Equation

Parameters

Diagram

Calculate Inductance:              top

Parameter

Value

Units

Special Values

Inputs:

Ra (array radius)
Rb (tube radius)
  Rc (rod radius)  
  N (# of rods)    
  er (diel. const.)    
  L (length)  
 

Outputs:  

L (inductance)

C (capacitance)

  Z (impedance)    

 

Output Format:                                                        top

Select Format: Scientific Engineering Fixed

 

Notes:                                                                       top

bullet
Leave length at 1 meter to get L' and C' in per meter units.
bullet
You can enter all radii as diameters instead, since ratios are taken.
bullet
Tube diameter can be smaller that array diameter, Ra and Rb are switched in this case.
bullet
The first term in the equation for L' is exactly the impedance of coax with Ra and Rb.  So, you can think of the second term as the addition inductance due to replacing one conductor with rods.
bullet
Sources: 
bullet
Ron Boller who gives his original source as "Russel".
bullet
Capacitance is my own derivation.

Copyright 2006  Raymond J. Allen