Miniaturized Coplanar Bandpass/Bandstop Filter Using Meander Serpentine Shape Shunt/Open-Stubs

This paper presents a design of a new compact bandpass filter in coplanar waveguide implementation composed of meander serpentine shape shunt-stubs. The meander serpentine shape shunt-stubs allow to increase the inductive loading and thus to reduce the size of the filter. The proposed filter has two transmission zeros on both sides of the passband. The equivalent circuit model has been proposed to describe the filter behavior. The measured center frequency, bandwidth and insertion loss are 5 GHz, 50% and 0.5 dB, respectively. The geometrical size of the proposed filter is 20times13.2 mm². Good agreements between both measured and simulated results have been observed. Finally, proposed bandpass filter has been transformed to bandstop filter and has been described.