QUASI-STATIC DESIGN TECHNIQUE FOR MM-WAVE MICROMACHINED FILTERS WITH LUMPED ELEMENTS AND SERIES STUBS

This paper describes micromachined, membrane-supported low-pass and ba ndpass filters which are suitable for microwave and millimeter-wave (m m-wave) application, The designs are realized in coplanar-waveguide (C PW) form using short- and open-end series stubs with integrated metal- insulator-metal (MIM) capacitors, and are compact in lateral and longi tudinal dimensions, A computationally efficient analysis has been deve loped for the design and characterization of the filters, The techniqu e is based on a quasi-static coupled-line (CL) treatment of the series stubs, and uses normal mode impedance parameters, which are calculate d with the spectral-domain approach (SDA), Due to the broad TEM-bandwi dth of the membrane-supported transmission lines, the method can accur ately predict filter responses well into the rejection band, To demons trate the above claims, the measured and simulated S-parameters of a 0 .3 mm x 2.2 mm low-pass Alter with a cutoff frequency at 17 GHz, and a second passband at 115 GHz, are presented, The new approach is also u sed in the design of bandpass filters which exhibit 1.5-2-dB insertion loss and bandwidths around 10%.