Power-dependent bandstop filters for frequency-selective limiting

Abstract

Abstract-The use of a power-dependent coupling structure that allows a cul-de-sac bandstop filter topology to continuously transform between a resonant all-pass response and a bandstop filter response with increasing input power is shown. In contrast to limiter devices that provide a wideband short circuit or ferrite resonance under high-power excitation, the concept presented in this paper provides the ability to design limiters with frequencyselectivity and without magnetic materials. For verification, a third-order power-dependent bandstop filter was designed and fabricated. It has a center frequency of 2.15 GHz, 3 dB bandwidth of 400 MHz, 1 dB limiting threshold of approximately 25 dBm, a response time of 10 ns, and provides over 16 dB of limiting.