AQ-Enhanced 3.6 GHz, Tunable, Sixth-Order BandpassFilter Using 0.18 μm CMOS

[摘要] An experimental filter was designed to operate at 3.6   GHz using mainstream 0.18  μm CMOS. In the design, theQ-enhancement technique was used to overcome the low-Qcharacteristics of the CMOS on-chip inductors. A sixth-order bandpass filterwith a wide passband and a high image rejection was built by cascading three stagesof second-orderQ-enhanced filters. A combination of three biquads with offset in centerfrequency provides wider tuning frequency and bandwidth. This high-performance filterprovides a 340   MHz tunable center frequency around 3.6   GHz, an imagerejection of 50   dB and a tunableQfrom 25 to 50 for a bandwidth adjustment from 95   MHz to 35  MHz. The filter achieves an18   dB voltage gain while consuming 130   mW of power at1.8   V DC supply. The chip occupies an area of900×900μm2including all the required bonding pads. The design provides a simplearchitecture to simplify tuning scheme for both frequency and bandwidth for practical use.The tunable ability of the design could be exploited in further study to be used asa channel-select filter in the gigahertz range.

[学科分类] 电子、光学、磁材料