Compact high rejection notch and DBR designed with slow-wave transmission lines

Shielded slow-wave coplanar waveguides are promising candidates for the development of miniaturized low-loss compact passive devices in millimeter-wave frequency band. In this paper, a high rejection notch based on a classical stub using a shielded slow-wave transmission line with high quality factor and slow-wave factor has been designed on a low-cost CMOS 0.35 μm technology, and characterized up to 30 GHz. This notch presents a very deep rejection of -20 dB at 10 GHz and a length reduction factor of 2 compared with a stub designed with classical transmission lines. These results open the opportunity to design, in CMOS technologies, filters based on slow-wave transmission lines, for frequencies above 10 GHz. Finally, based on these measurement results, a study for a dual behavior resonator filter working at 13.6 GHz has been carried out. The simulated filter exhibits a minimum insertion loss of 1.4 dB for a 28% relative bandwidth, leading to an unloaded quality factor equal to 20.