Electromagnetic interference by high power microwaves

Abstract

High power microwave (HPM) radiation with frequency>1 GHz may penetrate electronic systems through front or backdoor openings and propagate like the genuine signal. Sometimes parasitic resonance may amplify the HPM signal and cause havoc to these systems. The surface currents caused by HPM can also interfere with the normal signals and upset the functioning of devices. The HPM incident upon electronic components may damage them through mechanisms like adiabatic heating of the junction or punch-through of the depletion layer. High power microwave radiation generation studies were performed using the intense electron beam from the KALI-1000 Pulse Accelerator by the virtual cathode oscillator method. Various axial resonant cavities were used to optimise the microwave emission. A maximum power of 500 MW around 5 GHz was generated by using an axial resonant cavity with a resonant frequency of 5 GHz. The HPM was also used to study the effects on some electronic devices. The HPM caused damage to the op-amps and stopped the functioning of the personal computers. The HPM can also cause breakdown in the low-pressure devices like hydrogen thyratrons and cause spurious triggering in the control circuits that use them.