Design of field emitter devices for microwave and terahertz applications

Abstract

Simulations show that photomixing in resonant laser-assisted field emission can cause the emitted current to oscillate at frequencies from dc to over 100 THz, so this technique shows promise for new ultrawideband devices. However, it is necessary to find a means to couple these signals from the apex of the tip to an external load while avoiding the effects of dispersion of the bunched electron beam and the low-pass filter action caused by the series impedance of the electron beam and the shunting capacitance of the electrodes. We have designed a new type of device in which the signal would propagate as a surface wave on the emitting tip itself. The procedures for design are defined, and graphs are given to determine the dimensions. Examples of designs are presented, which include devices to generate signals from 10 GHz to 10 THz, from 100 GHz to 100 THz, and a device that would be simpler to construct for use from 10 MHz to 10 GHz.