Use of active networks to widen the spectrum of application of piezoelectric filters

This paper describes the design of active bulk acoustic wave (BAW) piezoelectric filters with properties that are unattainable with inductorless passive piezoelectric filters. Circuit realizations for wideband (fractional bandwidth of between 5% and 50%) bandpass filters (BPF), low pass filters (LPF), highpass filters (HPF), band reject filters (BRF), and tunable filter sections are proposed. This class of filter eliminates the characteristic restrictions related to the properties of the piezoelectric material. The proposed approach would be useful for the design of integrated circuit (IC) compatible thin film BAW piezoelectric filters over a wide frequency range of up to 1-2 GHz.<
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