Reconfigurable and tunable filters with flexible frequency and bandwidth response characteristics for wireless handsets and mobile terminals

Various compact reconfigurable and tunable filters for wireless handsets and mobile terminals covering most of popular wireless bands are studied and demonstrated in this work. Techniques for center frequency tuning coupled with bandwidth control features including the enabling of increasing fractional bandwidth and constant absolute bandwidth (ABW) are shown. Techniques for bandwidth reconfiguration with widely variable bandwidth states, convenient control of inter-resonator coupling as well as input and output coupling, are investigated. Tunable filter capable of switching from dual band to mono-band, selectivity enhancement and independent control of both frequency bands is also illustrated.