A Compacted CMOS K-Band Bandpass Filter Using Meandering Thin Film Microstrip and UC-PBG Structures

A compacted CMOS K-band bandpass filter incorporating meandering thin film microstrip and defective uniplanar compact photonic bandgap (UC-PBG) slow-wave structures for size reduction are presented. Benefited from the multilayer metal technology of the standard 0.18-mum CMOS process, meandering thin film microstrip and broadside-coupled structures with large coupling degree are properly constructed to realize bandpass filters with small insertion loss. The slow-wave effect of UC-PBG structure is investigated and a center frequency drop of 14% is achieved by the use of UC-PBG ground. A 3.6-dB loss 18 GHz filter with two transmission poles has been designed and implemented in standard 0.18-mum CMOS technology and only with an area of 0.34 mm².