MMIC gyrator bandstop filter with ultra-wideband tuning

This paper describes the first monolithic microwave integrated circuit bandstop filter using an inverted gyrator design. Operating up to 3 GHz it also represents the highest reported frequency application of a gyrator filter design. New active bias configurations were developed to achieve a stable gyrator response and assessment of the filters' tuning speed and control voltage requirements has shown its suitability for digital control in applications requiring frequency agility. The individual MMICs are capable of tuning a 3%, -30 dB attenuation bandwidth, over greater than an octave, and a series combination of two MMICs have a tuneable stopband from 0.7 to 3.3 GHz.