ELECTRIC FIELD SENSOR (D.) FREE FIELD   MODELS AD-20, AD-40, AD-55, AD-70, AD-80 & AD-100 PRODYN's AD Model electric field D-Dots are small to medium, free-space, high frequency sensors that measure time rate of change of electric displacement. Being differential, they have two asymptotic sensing elements accurately positioned on opposite sides of a common ground plate and have a radial output direction. Testing has shown the asymptotic design to have less capacitance and higher upper frequency characteristics, compared to the AFWL HSD design. The equation pertinent to this device is:                Vo =   R  Aeq     dD/dt   where        Vo                     =  sensor output (volts)      R                      =  sensor characteristic load impedance (100 ohms)      Aeq                    =  sensor equivalent area (m2)                                                       ®      ®      D                      =  magnitude of electric displacement vector (D =e o   E in Coul/m2)     The sensors are passive devices; therefore, an external power source is not required. The Model AD-20 39.4 cm output length can be increased to 1 meter maximum with SMA connectors. Model AD-40 and AD-100 are equipped with a 100 ohm twinaxial GR connector and with gas pressurization fittings. Length of output, output style, and connector type may be modified.   SPECIFICATIONS   Electrical AD-20 AD-80 AD-70 AD-55 AD-40 AD-100 Equivalent Area (Aeq) 1 x 10-4m2 3 x 10-4 1 x 10-3m2 3 x 10-3 1 x 10-2m2 1 x 10-1m2 Freq. Resp.(3 db pt.) >10 GHz >5.5 GHz >3.5 GHz >2 GHz >1 GHz >350 MHz Risetime (tr 10-90) <.029 ns <.064 ns <.11 ns <.17 ns <.29 ns <1.1 ns Maximum output (peak) + 150 V + 1 kV + 1 kV + 1.5 kV + 4 kV + 5 kV Output connector(s) SMA(Male) SMA(Male) SMA(Male) SMA(Male) GR-TCC* GR-TCC*   Physical     Mass 40g 260g 340g 448g 782g 2.8kg Dimensions A (cm) 39.40 17.78 38.58 36.35 47.50 61.60 B 2.54 5.08 7.60 10.16 14.00 28.26 C 1.09 1.95 3.31 5.66 10.00 31.12 D 0.16 0.32 0.32 0.48 0.51 0.64   * OTHER CONNECTOR TYPES ARE AVAILABLE