Coupled electric field sensors for DC target electric field detection
View Patent ↗In various embodiments, an apparatus for detecting electric fields is disclosed that includes an array of non-linear elements configured into an oscillator with each coupled to one or more electric-field sensing plates. In various embodiments, an output of the array produces a frequency that varies as a function of an electric field sensed by the one or more electric-field sensing plates.
1. An apparatus for detecting electric fields, comprising:
an array of an odd number of non-linear elements configured into an oscillator with each element coupled to a separate electric-field sensing plate, wherein an output of the array produces a frequency that varies as a function of an electric field sensed by the one or more electric-field sensing plates; and
wherein each element includes a control capacitor coupled to a respective sensing plate.
2. The apparatus of claim 1 , wherein each control capacitor has a toroidal configuration.
3. The apparatus of claim 1 , wherein each control capacitor has a control node configured to utilize charge density amplification to achieve electric field amplification.
4. The apparatus of claim 1 , wherein each nonlinear element further comprises:
an amplifier configured to receive an output of the control capacitor and to produce an output voltage;
an inner-loop feedback capacitor configured to receive the output voltage and to provide a feedback signal as an input to the amplifier;
a gain stage, the output of which is operatively coupled to an input of the control capacitor; and
a summing junction configured to provide as an input to the gain stage, the difference between the output voltage and an input voltage.
5. An apparatus for detecting electric fields, comprising:
an odd number of electric-field sensing plates;
an odd number of non-linear detection means serially configured into an oscillator with each non-linear detection means coupled to a separate electric-field sensing plate, and wherein an output of at least of the one non-linear detection means produces a frequency that varies as a function of an electric field sensed by the one or more electric-field sensing plates;
wherein each detection means includes a capacitive control means coupled to a respective sensing plate.
6. The apparatus of claim 5 , wherein each capacitive control means has a toroidal configuration.
7. The apparatus of claim 6 , wherein each capacitive control means has a control node configured to utilize charge density amplification to achieve electric field amplification.
8. The apparatus of claim 5 , wherein each nonlinear detection means further comprises:
an amplifier configured to receive an output of the capacitive control means and to produce an output voltage;
an inner-loop feedback capacitor configured to receive the output voltage and to provide a feedback signal as an input to the amplifier;
a gain stage, the output of which is operatively coupled to an input of the capacitive control means; and
a summing junction configured to provide as an input to the gain stage, the difference between the output voltage and an input voltage.