Sensing a time varying electric field includes a device or system including a spatial sensor array having one or more transistors, a circuit including a resistor connected to each of the transistors, an analog-to-digital converter (ADC) to each circuit which convert an analog voltage outputs to digital form, and an antenna to each of the transistors. The antennas sense the time varying electric field and modulate current through their respective transistors. The spatial sensor array may be stationary or in motion during the sensing.