Abstract: An apparatus and method for measuring a target environmental variable (TEV) that employs a film-bulk acoustic resonator with motion plate. The film-bulk acoustic resonator (FBAR) includes an acoustic reflector formed in an FBAR wafer and a surface. A first electrode is formed on the surface of the acoustic reflector and has a surface. A piezoelectric layer is formed on the surface of the first electrode and has a surface. A second electrode is formed on the surface of the piezoelectric layer. A motion plate is suspended in space at a predetermined distance relative to the surface of the second electrode and is capacitively coupled to the FBAR.

Abstract: Embodiments of the acoustic galvanic isolator comprise a carrier signal source, a modulator connected to receive an information signal and the carrier signal, a demodulator, and an electrically-isolating acoustic coupler connected between the modulator and the demodulator. The acoustic coupler comprises no more than one decoupled stacked bulk acoustic resonator (IDSBAR). An electrically-isolating acoustic coupler based on a single IDSBAR is physically small and is inexpensive to fabricate yet is capable of passing information signals having data rates in excess of 100 Mbit/s and has a substantial breakdown voltage between its inputs and its outputs.

Abstract: The band-pass filter has a stacked pair of film bulk acoustic resonators (FBARs) and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

Abstract: Embodiments of the acoustic galvanic isolator comprise a carrier signal source, a modulator connected to receive an information signal and the carrier signal, a demodulator, and, connected between the modulator and the demodulator, an electrically-isolating acoustic coupler comprising an electrically-isolating film acoustically-coupled transformer (FACT).

Abstract: The temperature-compensated film bulk acoustic resonator (FBAR) device comprises an FBAR stack. The FBAR stack comprises an FBAR and a temperature-compensating element. The FBAR is characterized by a resonant frequency having a temperature coefficient, and comprises opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element has a temperature coefficient on which the temperature coefficient of the resonant frequency depends at least in part. The temperature-compensating element has a temperature coefficient opposite in sign to the temperature coefficient of the piezoelectric element.

Abstract: The band-pass filter has an upper film bulk acoustic resonator (FBAR), an upper FBAR stacked on the lower FBAR, and, between the FBARs, an acoustic decoupler comprising a layer of acoustic decoupling material. Each of the FBARs has opposed planar electrodes and a piezoelectric element between the electrodes. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

Abstract: One embodiment of the film acoustically-coupled transformer (FACT) includes a decoupled stacked bulk acoustic resonator (DSBAR) having a lower film bulk acoustic resonator (FBAR) an upper FBAR stacked on the lower FBAR, and, between the FBARs, an acoustic decoupler comprising a layer of acoustic decoupling material. Each FBAR has opposed planar electrodes with a piezoelectric element between them. The FACT additionally has first terminals electrically connected to the electrodes of one FBAR and second terminals electrically connected to the electrodes of the other FBAR. Another embodiment has decoupled stacked bulk acoustic resonators (DSBARs), each as described above, a first electrical circuit interconnecting the lower FBARs, and a second electrical circuit interconnecting the upper FBARs. The FACT provides impedance transformation, can linking single-ended circuitry with balanced circuitry or vice versa and electrically isolates primary and secondary.

Abstract: The film acoustically-coupled transformer (FACT) has a first and second decoupled stacked bulk acoustic resonators (DSBARs). Each DSBAR has a lower film bulk acoustic resonator (FBAR), an upper FBAR atop the lower FBAR, and an acoustic decoupler between them FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. A first electrical circuit interconnects the lowers FBAR of the first DSBAR and the second DSBAR. A second electrical circuit interconnects the upper FBARs of the first DSBAR and the second DSBAR. In at least one of the DSBARs, the acoustic decoupler and one electrode of the each of the lower FBAR and the upper FBAR adjacent the acoustic decoupler constitute a parasitic capacitor. The FACT additionally has an inductor electrically connected in parallel with the parasitic capacitor. The inductor increases the common-mode rejection ratio of the FACT.

Abstract: Embodiments of an acoustically-coupled transformer have a first stacked bulk acoustic resonator (SBAR) and a second SBAR. Each of the SBARs has a lower film bulk acoustic resonator (FBAR) and an upper FBAR, and an acoustic decoupler between the FBARs. The upper FBAR is stacked atop the lower FBAR. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element is characterized by a c-axis. The c-axes of the piezoelectric elements of the lower FBARs are opposite in direction, and the c-axes of the piezoelectric elements of the upper FBARs are opposite in direction. The transformer additionally has a first electrical circuit connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR, and a second electrical circuit connecting the upper FBAR of the first SBAR to the upper FBARs of the second SBAR.

Abstract: The decoupled stacked bulk acoustic resonator (DSBAR) device has a lower film bulk acoustic resonator (FBAR), an upper FBAR stacked on the lower FBAR, and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler has acoustic decoupling layers of acoustic decoupling materials having different acoustic impedances. The acoustic impedances and thicknesses of the acoustic decoupling layers determine the acoustic impedance of the acoustic decoupler, and, hence, the pass bandwidth of the DSBAR device. Process-compatible acoustic decoupling materials can then be used to make acoustic decouplers with acoustic impedances (and pass bandwidths) that are not otherwise obtainable due to the lack of process-compatible acoustic decoupling materials with such acoustic impedances.

Abstract: The encapsulated film bulk acoustic resonator (FBAR) device comprises a substrate, an FBAR stack over the substrate, an element for acoustically isolating the FBAR stack from the substrate, encapsulant covering the FBAR stack, and an acoustic Bragg reflector between the top surface of the FBAR stack and the encapsulant. The FBAR stack comprises an FBAR and has a top surface remote from the substrate. The FBAR comprises opposed planar electrodes and a piezoelectric element between the electrodes. The acoustic Bragg reflector comprises a metal Bragg layer and a plastic Bragg layer juxtaposed with the metal Bragg layer.

Abstract: An apparatus and method for detecting a target environmental variable (TEV). A first film-bulk acoustic resonator (FBAR) oscillator that includes a first FBAR with a first response to the target environmental variable generates a first frequency. A second film-bulk acoustic resonator (FBAR) oscillator that includes a second FBAR with a second response to the target environmental variable generates a second frequency. A circuit that is coupled to the first FBAR oscillator and the second FBAR oscillator determines the target environmental variable (e.g., changes in the TEV) based on the first frequency and the second frequency.

Abstract: The film bulk acoustic resonator (FBAR) device comprises a substrate, an acoustic Bragg reflector over the substrate, a piezoelectric element over the acoustic Bragg reflector, and a remote-side electrode over the piezoelectric element. The acoustic Bragg reflector comprises a metal Bragg layer juxtaposed with a plastic Bragg layer. The large ratio between the acoustic impedances of the plastic material of the plastic Bragg layer and the metal of the metal Bragg layer provides sufficient acoustic isolation between the FBAR and the substrate for the frequency response of the FBAR device to exhibit minor, if any, spurious artifacts arising from undesirable acoustic coupling between the FBAR and the substrate.

Abstract: An apparatus including vertically separated acoustic resonators are disclosed. The apparatus includes a first acoustic resonator on a substrate and a second acoustic resonator vertically separated above the first acoustic resonator. Because the resonators are vertically separated above another, total area required to implement the resonators is reduced thereby savings in die size and cost are realized. The vertically separated resonators are supported by standoffs that are fabricated on the substrate, or on a resonator.

Abstract: The band-pass filter has first terminals, second terminals, a first decoupled stacked bulk acoustic resonator (DSBAR), a second DSBAR, and an electrical circuit connecting the first DSBAR and the second DSBAR in series between the first terminals and the second terminals. Each DSBAR has a first film bulk acoustic resonator (FBAR), a second FBAR and an acoustic decoupler between the FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes.

Abstract: The film acoustically-coupled transformer (FACT) has decoupled stacked bulk acoustic resonators (DSBARs), a first electrical circuit and a second electrical circuit. Each of the DSBARs has a lower film bulk acoustic resonator (FBAR), an upper FBAR and an acoustic decoupler. The upper FBAR is stacked on the lower FBAR and the acoustic decoupler is located between the FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The first electrical circuit interconnects the lower FBARs. The second electrical circuit interconnects the upper FBARs. The FBARs of one of the DSBARs differ in electrical impedance from the FBARs of another of the DSBARs. The FACT has an impedance transformation ratio greater than 1:m2, where m is the number of DSBARs. The actual impedance transformation ratio depends on the ratio of the impedances of the FBARs.

Abstract: Embodiments of an acoustically-coupled transformer have a first stacked bulk acoustic resonator (SBAR) and a second SBAR. Each of the SBARs has a lower film bulk acoustic resonator (FBAR) and an upper FBAR, and an acoustic decoupler between the FBARs. The upper FBAR is stacked atop the lower FBAR. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element is characterized by a c-axis. The c-axes of the piezoelectric elements of the lower FBARs are opposite in direction, and the c-axes of the piezoelectric elements of the upper FBARs are opposite in direction. The transformer additionally has a first electrical circuit connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR, and a second electrical circuit connecting the upper FBAR of the first SBAR to the upper FBARs of the second SBAR.

Abstract: An apparatus including vertically separated acoustic resonators are disclosed. The apparatus includes a first acoustic resonator on a substrate and a second acoustic resonator vertically separated above the first acoustic resonator. Because the resonators are vertically separated above another, total area required to implement the resonators is reduced thereby savings in die size and cost are realized. The vertically separated resonators are supported by standoffs that are fabricated on the substrate, or on a resonator.

Abstract: The band-pass filter has a stacked pair of film bulk acoustic resonators (FBARs) and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler has a single layer of acoustic decoupling material having a nominal thickness equal to an odd integral multiple of one quarter of the wavelength in the acoustic decoupling material of an acoustic wave having a frequency equal to the center frequency. The acoustic decoupling material comprises plastic. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

Abstract: An embodiment of the acoustically-coupled transformer has first and second stacked bulk acoustic resonators (SBARs) each having a stacked pair of film bulk acoustic resonators (FBARs) with an acoustic decoupler between the FBARs. Each FBAR has opposed planar electrodes with piezoelectric material between the electrodes. A first electrical circuit connects one FBARs of the first SBAR to one FBAR of the second SBAR, and a second electrical circuit connects the other FBAR of the first SBAR to the other FBAR of the second SBAR. The c-axis of the piezoelectric material of one of the FBARs is opposite in direction to the c-axes of the piezoelectric materials of the other three FBARs. This arrangement substantially reduces the amplitude of signal-frequency voltages across the acoustic decouplers and significantly improves the common mode rejection of the transformer. This arrangement also allows conductive acoustic decouplers to be used, increasing the available choice of acoustic decoupler materials.