To realize a compact device that detects phase or controls phase or an amplitude with high sensitivity, a signal controller includes: a linear conductor having a first end fixed to a negative electrode and a second end serving as a free end; a positive electrode facing the free end with a small gap therebetween; a first signal source that applies a voltage between the negative electrode and the positive electrode, the voltage applied being variable; a driving electrode that applies an electric field to a space around the conductor, the electric field having a component perpendicular to the lengthwise direction of the conductor; and a second signal source that applies an AC signal to the driving electrode. The signal processor can be a device for controlling or modulating phase or amplitude.

To realize a compact device that detects phase or controls phase or an amplitude with high sensitivity, a signal controller includes: a linear conductor having a first end fixed to a negative electrode and a second end serving as a free end; a positive electrode facing the free end with a small gap therebetween; a first signal source that applies a voltage between the negative electrode and the positive electrode, the voltage applied being variable; a driving electrode that applies an electric field to a space around the conductor, the electric field having a component perpendicular to the lengthwise direction of the conductor; and a second signal source that applies an AC signal to the driving electrode. The signal processor can be a device for controlling or modulating phase or amplitude.

To realize a compact device that detects phase or controls phase or an amplitude with high sensitivity, a signal controller includes: a linear conductor having a first end fixed to a negative electrode and a second end serving as a free end; a positive electrode facing the free end with a small gap therebetween; a first signal source that applies a voltage between the negative electrode and the positive electrode, the voltage applied being variable; a driving electrode that applies an electric field to a space around the conductor, the electric field having a component perpendicular to the lengthwise direction of the conductor; and a second signal source that applies an AC signal to the driving electrode. The signal processor can be a device for controlling or modulating phase or amplitude.