Abstract: A method of manufacturing a filter circuit including series and parallel coupled BAW resonators is given which compensates for frequency tolerances of the resonators which are due to the manufacturing process. The new method includes measuring a resonance frequency of at least one type of the BAW resonators produced on a wafer and defining a deviation from a desired frequency. A trimming layer is then deposited onto the entire wafer. At last, a thickness portion of the trimming layer is selectively removed, the portion being dependent on a location on the wafer and on the calculated deviation of the resonance frequency at this location.

Abstract: An impedance matching method which is used to save electrical energy by virtue of the fact that the method switches between modes for controlling impedance matching and modes for regulation of the impedance matching depending on the situation. An algorithm which, on the basis of control signals from an external circuit environment, controls or regulates the impedance of a variable-impedance circuit element is implemented in a logic circuit LC.

Abstract: An electroacoustic resonator includes a resonator area for propagating an acoustic wave and a resonator surface area configured so that, when an input signal power of 0 dBm is applied at a resonant frequency fr, power density in the resonator area does not exceed 40 dBm/m2. An electroacoustic resonator includes a resonator surface area configured so that a critical input signal power PIIPn at an nth-order intercept point IPn is at least 80 dBm for n=2 and/or 80 dBm for n=3.

Abstract: An impedance matching circuit for matching planar antennas includes a signal path with a signal path input and a signal path output. A first capacitive element with variable capacitance is connected between the signal path input and signal path output. A second capacitive element with variable capacitance is connected between the signal path and ground. A first inductive element is connected between the signal path input and ground. A second inductive element is connected between the signal path output and ground. An antenna line with an impedance between 30 and 60 ohm is connected to the signal path output.

Abstract: A circuit includes a signal path having a node between a signal path input and a signal path output. A first inductive element is connected between the signal path input and the node and a first capacitive element whose capacitance is variably adjustable is connected between the node and the signal path output. A second variable-capacitance capacitive element is connected between the signal path input and ground. A second inductive element is connected between the node and ground, and a third inductive element is connected between the signal path output and ground.

Abstract: A switchable capacitive element having an adjustable capacitance and an improved quality factor is specified. To this end, the characteristic variables of the switchable capacitive element are optimized in accordance with the equations cited in the description.

Abstract: The invention relates to a filter operating with bulk acoustic waves, comprising at least one first resonator and at least one second resonator. In the at least one first and second resonator, a longitudinal acoustic mode is capable of propagation, for which normal dispersion is adjusted in the first resonator and abnormal dispersion in the second resonator by selection of the material and the relative layer thicknesses. In particular, the power compatibility of the filter at the higher frequency edge of its passband can be improved.

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: An impedance matching method which is used to save electrical energy by virtue of the fact that the method switches between modes for controlling impedance matching and modes for regulation of the impedance matching depending on the situation. An algorithm which, on the basis of control signals from an external circuit environment, controls or regulates the impedance of a variable-impedance circuit element is implemented in a logic circuit LC.

Abstract: A highly integrated electrical module is specified which comprises a filter circuit and a balun circuit. The space requirement is reduced by circuit components of the balun circuit being arranged at least in part on an inner side of the housing of the filter circuit.

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 method of manufacturing a filter circuit including series and parallel coupled BAW resonators is given which compensates for frequency tolerances of the resonators which are due to the manufacturing process. The new method includes measuring a resonance frequency of at least one type of the BAW resonators produced on a wafer and defining a deviation from a desired frequency. A trimming layer is then deposited onto the entire wafer. At last, a thickness portion of the trimming layer is selectively removed, the portion being dependent on a location on the wafer and on the calculated deviation of the resonance frequency at this location.

Abstract: A method for the impedance matching of front end circuits to antennas in mutually different transmission and reception frequency ranges is specified. A suitable matching circuit is furthermore specified. The impedance matching in a transmission frequency range is determined such that an excessively poor impedance matching in a reception frequency range is prevented in this case.

Abstract: A circuit is proposed by means of which a ceramic component having two electrodes can be provided with a uniform, but periodically alternating BIAS voltage. The component has properties dependent on the level of the BIAS voltage and, for the purpose of an increased service life, is connected to a generator for generating a BIAS voltage and to means for periodically reversing the polarity of the BIAS voltage present at the electrodes. In a method for operating the component having variable properties, a uniform BIAS voltage, the polarity of which is periodically reversed, however, is applied to the electrodes, and the service life of the component is thus increased.

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: 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: 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: An electroacoustic resonator includes a resonator area for propagating an acoustic wave and a resonator surface area configured so that, when an input signal power of 0 dBm is applied at a resonant frequency fr, power density in the resonator area does not exceed 40 dBm/m2. An electroacoustic resonator includes a resonator surface area configured so that a critical input signal power PIIPn at an nth-order intercept point IPn is at least 80 dBm for n=2 and/or 50 dBm for n=3.

Abstract: The invention relates to a resonator operating with bulk acoustic waves (BAW resonator, BAW=Bulk Acoustic Wave) and band-pass filters constructed of such resonators. To increase the edge steepness of the transmission band of a BAW band-pass filter, the invention proposes reducing the effective coupling of a BAW resonator by using the connection in parallel of a BAW resonator and a capacitor instead of only one resonator. In addition, to increase the edge steepness of the transmission band, the use of a connection of coupled BAW resonators in the serial branch of a filter circuit with another resonator or resonator stack in the parallel branch of the filter circuit is proposed, the additional resonator or resonator stack being connected to the center electrode of the resonator stack specified initially.

Abstract: A frequency separating unit includes an antenna unit, a first signal path, a second signal path, 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 is 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.