Interdigital microstrip filters as protection devices against ultrawideband pulses

Standard protection concepts against transients employing nonlinear elements like sparkgaps or Zener diodes cannot provide an optimal protection against interferences caused by ultrawideband (UWB) pulses. Therefore this paper discusses the use of linear filters as protection against UWB-pulses. Due to advantages in several areas for example cost-effective production and high voltage capability this study focuses an implementation of microstrip bandpass filters with very steep edges. To reduce the overall size of the filters, their realization as interdigital structures has been investigated. Finally, the filters are characterized in frequency domain and with UWB-stress in time domain.