Switchable waveguide iris filter using planar dipoles

A new concept of switching on and off high Q-factor bandpass filters is presented. Cheap, planar, low Q-factor circuits are proposed to disable 3D filters. Reconfigurable dipoles are used to disable resonance and turn the filter off, rather than adjusting the resonance frequency or coupling. Here wire bonded dipoles on quartz substrates inside the waveguide structure are used for switching the bandpass filters. 3-pole bandpass filters are proposed for concept demonstration. The dipoles are inserted in each cavity of the iris waveguide filter. Central frequency is 24GHz and bandwidth 500MHz. Simulation results show good performance. The fabricated filter shows good correlation between the measured and simulated performance. The bandpass response is completely off, when the dipoles are “switched on”/ connected with bondwires, confirming the introduced concept. The insertion loss is expected to be significantly reduced by choosing a superior fabrication method of the waveguide.