LCnetgen Example 2, E-Field Antenna

An E-field dipole probe consisting of two 10cm diameter spheres positioned vertically with centers 1 metre apart. The dipole center is 2.5 metres off the ground.

Input File

The input file dipole.in contains

   height = 2.5          ; Height of the dipole center
   sphere_diam = 0.1     ; 10cm diameter spheres
   spacing = 1.0         ; Sphere centers one metre apart
   preamp_diam = 0.05    ; Space for preamp at center of dipole
   
   electrode {
   
      name upper_sphere
   
      sphere {
         center 0, 0, height + spacing/2
         radius sphere_diam/2
      }
   
      wire {
         end1 0, 0, height + spacing/2 - sphere_diam/2
         end2 0, 0, height + preamp_diam/2
         wirad 24 awg
      }
   }
   
   electrode {
   
      name lower_sphere
   
      sphere {
         center 0, 0, height - spacing/2
         radius sphere_diam/2
      }
   
      wire {
         end1 0, 0, height - spacing/2 + sphere_diam/2
         end2 0, 0, height - preamp_diam/2
         wirad 24 awg
      }
   }
   
   ground {
      center 0, 0, 0
      axis 0, 0
   }
   
   field {
      electric 0, 0   ; Vertical E-field
   }
   

   lcng -o spice dipole

Test Circuit One

Create a test circuit with a resistor to ground from each sphere, representing the bias resistors of a differential front-end amplifier. The 5th pin of the sub-circuit is an input which sets the field strength. This is connected to a 1V AC source to represent a 1 V/m field in the model.

The file dipole-test.spice contains

   Dipole
   .OPTIONS NOMOD NOPAGE
   .AC DEC 10 1 10K
   .PRINT AC V(2) V(1)
   
   .INCLUDE dipole.spice
   
   * 1 volt AC applied to pin 3
   Vin 3 0 DC 0 AC 1.0 180
   
   X1 0 1 2 3 dipole
   RB1 0 1 1G
   RB2 0 2 1G
   
   .END

   ngspice -b dipole-test.spice > dipole-test.out