Abstract: A bulk acoustic wave resonator includes a resonator region having electrodes and a piezoelectric layer among the electrodes. The piezoelectric layer has a groove that bounds at least part of an electroacoustically active region of the piezoelectric layer. A depth of the groove is at least 50% of a thickness of the piezoelectric layer.

Abstract: A module for a mobile radio device is proposed, whose central element is a multiswitch MS, which, as desired, can connect outputs for transmission and/or reception branches SZ, EZ of different mobile radio systems to an antenna ANT. The module is suitable for a multiband operation and, optionally, additional multimode operations and includes at least one pair of outputs for transmission and reception branches of a frequency duplexed mobile radio system. Between each output of the multiswitch and the antenna, a matching element is provided, which allows an electrical matching of the branches to be connected to it. The duplex operation is carried out via separate transmission and reception filters, or on the switch via separate outputs for transmission and reception branches.

Abstract: The invention relates to a bulk acoustic wave filter comprising at least one first resonator and at least one second resonator. A longitudinal acoustic mode for which normal dispersion is adjusted in the first resonator and abnormal dispersion is adjusted for the second resonator by selecting the material and the relative layer thicknesses, is able to propagate in the resonators, thus making it possible to improve especially the power compatibility of the filter at the higher frequency edge of the passband thereof.

Abstract: An electrical component includes a substrate, a first electrode layer, a structured growth layer that is thinner than the first electrode layer, a piezoelectric layer, and a second electrode layer. The growth layer is on the first electrode layer, the growth layer is structured relative to the first electrode layer, and the growth layer has a smaller surface area than the first electrode layer. The growth layer may be selected to support ordered growth relative to the piezoelectric layer.

Abstract: An electrical circuit that includes an electric four-terminal network is disclosed. The electric four-terminal network includes a first electrical port with a first terminal and a second terminal and a second electrical port with a first terminal and a second terminal. The electrical circuit also includes a first shunt branch between the second terminal of first electrical port and ground.

Abstract: A resonator operating with bulk acoustic waves includes a resonator stack. The resonator stack includes a resonator area configured to allow propagation of an acoustic main mode and an acoustic secondary mode. The resonator stack also includes an acoustic mirror that includes a first partial mirror for locking in the acoustic main mode in the resonator area and a second partial mirror for locking in the secondary mode in a resonator space.

Abstract: A filter for use with bulk acoustic waves includes an input port and an output port. The input port and the output port are symmetrically operable. Signal paths extend from a terminal of the input port to a terminal of the output port. Bulk acoustic wave resonators are in the signal pats. The bulk acoustic wave resonators are arranged symmetrically in the signal paths. A complex impedance associated with each signal path is provided for electrically matching to a corresponding connection.

Abstract: Disclosed is a resonator that is mounted on a substrate, operates with acoustic bulk waves, and is disposed above an acoustic mirror. According to the invention, the basic mode of the acoustic bulk wave that can be generated in the resonator is suppressed while a higher mode can be excited in parallel and be utilized for the resonator by adjusting the acoustic mirror.

Abstract: An arrangement includes a substrate, a filter, a first bulk acoustic wave resonator, a second bulk acoustic wave resonator, and a large surface covering. The first bulk acoustic wave resonator includes a first electrode and a second electrode and is arranged flatly on the substrate. The second bulk acoustic wave resonator includes a first electrode and a second electrode and is arranged flatly on the substrate. The large-surface covering includes a metal layer over the substrate. The metal layer is connected to a ground terminal.

Abstract: A frequency separating unit includes an antenna unit, a first signal path, a second signal path, a first band-pass filter in the first signal path, a second band-pass filter in the second signal path, and a matching circuit between the antenna unit and the second band-pass filter in the second signal path. The matching circuit includes a shunt arm to ground that includes a first impedance component, and a parallel circuit that includes an acoustic wave resonator and a second impedance component. The matching circuit in configured to operate as a phase shifter and to produce a substantially open circuit at an input of the second filter in a pass band of the first band-pass filter.

Abstract: A bulk acoustic wave resonator includes an acoustically active area where an acoustic wave is excitable, and a transition area adjacent to an outside edge of the acoustically active area. A critical frequency of the acoustic wave in the transition area differs from a critical frequency of the acoustic wave in the active area. The transition area includes an additional layer. The bulk acoustic wave resonator includes electrodes for electrically connecting to electrical supply lines. The additional layer is irregular in areas adjacent to junction areas between the electrical supply lines and the resonator.

Abstract: A bulk acoustic wave resonator includes a resonator region having electrodes and a piezoelectric layer among the electrodes. The piezoelectric layer has a groove that bounds at least part of an electroacoustically active region of the piezoelectric layer. A depth of the groove is at least 50% of a thickness of the piezoelectric layer.

Abstract: A functional block of a front-end circuit for a communication device, which is employed for multi-band and/or multi-mode operation, is proposed. By positioning, according to this invention, a pin diode switch in one of the parallel signal paths instead of positioning it on the input side before separating the signal paths, it is possible to do without an impedance transformation network on the input side and to thus reduce the signal loss and the space requirement of the circuit. In a further configuration, the signal paths preferably associated with the adjacent frequency bands are combined on the output side, whereby the further processing of the signals corresponding to the different frequency bands takes place in one path. This for example allows a chip set designed for (n?1) frequency bands to be used in a transmission system designed for n bands. Another embodiment of this invention enables monitoring of the received signal of a system even during operation of the other mode in a multi-mode system.

Abstract: A transceiver circuit includes a duplexer having a transmit band for transmit signals and a receive band for receive signals, and an antenna circuit electrically connected to the duplexer. The antenna circuit is configured to generate at least one stop band in a frequency range in which noise signals are received. An intermodulation product of the noise signals and the transmit signals is in the receive band of the transceiver circuit.

Abstract: The invention relates to a duplexer with a transmit-receive path, which branches on the output side into a receive path and a transmit path. The receive path is preferably designed on the input side for transmitting an asymmetric signal and on the output side for transmitting a symmetric signal. A receive filter, which operates with surface acoustic waves, is arranged in the receive path. A transmit filter, which operates with bulk acoustic waves, is arranged in the transmit path. The filters are preferably constructed as separate chips, which are mounted on a common carrier substrate.

Abstract: The invention pertains to an oscillator with a resonator element and a control element for adjusting the resonant frequency of the resonator element to a plurality of different values, wherein the resonator element consists of at least one resonator. The control element can be realized as a control layer for controlling the propagation speed of the acoustic wave in the resonator. The control element can alternatively be constructed as a switch element and be used for switching different sub-branches of a resonator element constructed as a resonator magazine or a resonator bank. A trimming element, with which fine-tuning of the oscillator frequency is possible, is preferably also provided.

Abstract: In an electrical component with thin-layer construction that has a piezoelectric functional layer, the layer quality of the functional layer is improved in that a growth layer is provided between the electrode layer and the piezoelectric layer. Thus the function of the electrode layer is separated from that of a growth-supporting layer, whereby the functions can be optimized using separate layers independent of one another. Inventive components can be embodied as BAW resonators, thin-layer piezo-actuators, or piezo-sensors.

Abstract: Overlapped electrodes of an electrical component are dimensioned in such a way that when there is translational displacement of one electrode in relation to the electrode situated opposite, their area of overlap remains within a manufacturing tolerance ?/2, and also remains constant within the tolerance limits when there is a simultaneous rotation of the electrodes with respect to one another. This is achieved in that the intersecting edge pairs of the overlapping electrodes are designed parallel to one another, whereby the length, measured in the direction parallel to the respective edge pair, of the corresponding electrode everywhere exceeds by ? the corresponding length of the area of overlap.

Abstract: A duplexer has an asymmetrical antenna port and a symmetrical reception output, and therefore can be interconnected (without any intermediate stages) to an amplifier with a differential input. A reception bandpass filter is arranged in the reception path of the duplexer. The reception bandpass filter can have the functionality of a balun. The transmission input of the duplexer can be designed symmetrically, in which case a transmission bandpass filter arranged in the transmission path should be designed symmetrically on the input side. The impedance of the antenna port of the duplexer can differ from the impedance of the reception output or the transmission input. No intermediate stages (such as a balun or—in cases of impedances that differ between the duplexer and its corresponding amplifier—an impedance transformer) are required between the duplexer and the amplifier that is interconnected (whether before or after) in the transmission or reception path.

Abstract: A functional block of a front-end circuit for a communication device, which is employed for multi-band and/or multi-mode operation, is proposed. By positioning, according to this invention, a pin diode switch in one of the parallel signal paths instead of positioning it on the input side before separating the signal paths, it is possible to do without an impedance transformation network on the input side and to thus reduce the signal loss and the space requirement of the circuit. In a further configuration, the signal paths preferably associated with the adjacent frequency bands are combined on the output side, whereby the further processing of the signals corresponding to the different frequency bands takes place in one path. This for example allows a chip set designed for (n?1) frequency bands to be used in a transmission system designed for n bands. Another embodiment of this invention enables monitoring of the received signal of a system even during operation of the other mode in a multi-mode system.