Multilayered Lossy -Bandstop- Filter- Based Negative-Group- Delay RF Circuit With Broadband Input-Reflectionless Behavior

A multilayered lossy-bandstop-filter-(BSF)-based negative-group-delay (NGD) RF circuit with wide-band input-reflectionless behavior is presented. It is designed by using a los-sy-complementary-diplexer-based topology, in which the NGD circuit is built with a microstrip lossy-BSF network printed on the top layer, whilst a resistively-terminated lossy vertical transition is exploited to absorb the reflected RF -input-signal energy to attain perfect matching at the center frequency to and broadband input-quasi-reflectionless behavior. The RF operational principle of the devised NGD circuit is detailed and its properties in terms of NGD profile and power-attenuation responses are graphically discussed. As practical validation, a two-layered microstrip-lossy-BSF -based NGD circuit prototype is developed and measured with power-attenuation level of 19.62 dB and NGD depth of −0.82 ns at 0.996 GHz, NGD bandwidth of 417 MHz (i.e., 41.8%), and input-power-matching levels above 9.18 dB from DC to 2.5 GHz.