Waveguide Energy-Selection-Filter Switch Array

This paper presents a waveguide energy-selection-filter switch (ESFS) array for high-power microwave protection, which has a nonlinear transmission response depending on the power intensity of the incident wave. A prototype of nine unit-cells loaded with pin diodes is designed and measured. First, the relationship between the unit-cell dimension and frequency response is analyzed by the full-wave simulation, and an equivalent circuit is studied with numerical fitting. Then, the non-linear characteristics of the unit-cell for different power levels are observed by using an electric field probe. Subsequently, the array structure is designed with equivalent circuits made to evaluate the performance and the coupling effects between the array elements. At the same time, the influence of the number of elements on the transmission coefficient is discussed. Finally, the nonlinear and adaptive transmission characteristics of the ESFS array are demonstrated by the waveguide measurements, which show an isolation improvement of 19.5 dB for high-power microwave protection compared to a single ESFS unit. In addition, the protecting band is wider than that of a single unit.