Spyros Pipilos Yannis P. Tsividis Josef Fenk Yannis Papananos A Si 1.8 GHz RLC filter with tunable center frequency and quality factor. 1517-1525 1996 31 IEEE J. Solid State Circuits 10 https://doi.org/10.1109/4.540064 db/journals/jssc/jssc31.html#PipilosTFP96