Tunable and reconfigurable bandstop filters enabled by optically controlled switching elements

The authors report a novel approach for designing tunable and reconfigurable bandstop filters by employing bias-free optically-controlled photoconductive radio frequency (RF) switching elements. To verify the effectiveness of approach, filter with two stopbands centred at 4.05 4.75 GHz was designed using split-ring-coupled microstrip transmission line on RO3010 substrates. enable reconfigurability, micromachined Si chip thickness ∼73 μm embedded in gap each resonator. tuning reconfiguring are accomplished selectively illuminating chips fibre-coupled laser diodes wavelength 808 nm. By turning off diode, stop bands can be dynamically reconfigured. In addition, suppression band continuously independently tuned changing light intensity from 0 to 20 W/cm2. With geometric scaling, this is promising realizing class compact high-performance and/or circuits microwave mmW-THz region.