First results on SiGe BiCMOS capacitively-loaded Split Ring Resonators transmission line filters

This work reports the design of a compact on-chip transmission line filter implemented by loading a CoPlanar Waveguide (CPW) with a Split Ring Resonator (SRR). In the proposed design, a CPW transmission line is implemented on the top-most metal layer of a standard 0.13 μm SiGe BiCMOS stackup. Loading the CPW with a single-stage SRR results in a pass-band effect. In general, it would not be possible to lower the pass-band frequency of such type of on-chip filter below V-band without dramatically increasing the size of the SRR. To overcome this limitation, in this work the resonant frequency of the SRR is decreased by loading the rings with MIM capacitors. Results will show how the loading effect halves the filter pass-band frequency with respect to the unloaded configuration.