Abstract: A duplexer for connection with an antenna comprises an antenna port, a transmitting filter comprising bulk acoustic wave (BAW) resonators having a first antenna side impedance coupled with the antenna port, a receiving filter comprising BAW resonators having a second antenna side impedance coupled with the antenna port, and a shunt inductance coupled between the antenna port and ground. The shunt inductance and the first and second antenna side impedances of the transmitting filter and the receiving filter are selected in such a way that the shunt inductance turns the first and second input impedance in a negative direction in a Smith diagram.

Abstract: A BAW resonator includes a resonator region having a piezo-electric layer between two excitation electrodes, wherein an acoustic standing wave forms when operating the BAW resonator at a resonant frequency. Furthermore, the BAW resonator includes a leaky wave reflection structure formed to reflect leaky waves generated when operating the BAW resonator, wherein the leaky waves propagate in a direction differing from a propagation direction of the acoustic standing wave.

Abstract: A filter circuit comprises a balanced port, an unbalanced port and a substrate. A series circuit of a filter stage and a balun is disposed between the balanced port and the unbalanced port. The balun and the filter stage are formed on the substrate.

Abstract: A description is given of a BAW apparatus having a first BAW resonator and a second BAW resonator which are connected antiparallel to one another so as to reduce non-linear effects, in particular harmonics.

Abstract: A piezoelectric resonator includes a piezoelectric layer having a first resonance frequency temperature coefficient of a first sign, a first and a second electrode, the piezoelectric layer being arranged between the first and second electrodes, and a compensation layer arranged between the first electrode and the piezoelectric layer, of a compensation material having a second resonance frequency temperature coefficient of a second sign opposite to the first one, wherein the compensation material is provided with a modification material to increase a conductivity of the compensation layer in a direction of the first electrode and the piezoelectric layer.

Abstract: A BAW resonator includes a resonator region having a piezo-electric layer between two excitation electrodes, wherein an acoustic standing wave forms when operating the BAW resonator at a resonant frequency. Furthermore, the BAW resonator includes a leaky wave reflection structure formed to reflect leaky waves generated when operating the BAW resonator, wherein the leaky waves propagate in a direction differing from a propagation direction of the acoustic standing wave.

Abstract: A BAW resonator includes a first piezoelectric layer made of a material oriented toward a first direction, and a second piezoelectric layer made of a material oriented toward a second direction which is opposed to the first direction. The first piezoelectric layer and the second piezoelectric layer are acoustically coupled with each other.

Abstract: A duplexer comprising a transmit resonator device and a receive resonator device for filtering transmit and receive signals. The resonator device has a first BAW resonator for generating an acoustic wave signal from an input electric signal, a first acoustic delay for delaying the acoustic wave signal, and an intermediate BAW resonator for receiving the delayed acoustic wave signal at one end and converting the delayed acoustic wave signal to an electric signal. Through electrical coupling, the electric signal also appears at another end of the intermediate BAW resonator for generating a further acoustic wave signal at the other end. The resonator further comprises a second delay for delaying the further acoustic wave signal, and a second BAW resonator for producing an output electric signal from the delayed further acoustic wave signal. The duplexer can be used in a transceiver in a mobile phone.

Abstract: In a method for generating a protective cover for a device, where a substrate is provided, which comprises the device, first, a sacrificial pattern is generated on the substrate. The sacrificial pattern covers at least an area of the substrate, which comprises the device. Then, a polymer layer is deposited, which comprises at least on sacrificial pattern. Then, an opening will be formed in the polymer layer to expose a portion of the sacrificial pattern. Then, the sacrificial pattern will be removed and the formed opening in the polymer layer is closed.

Abstract: A filter circuit comprises a balanced port, an unbalanced port and a substrate. A series circuit of a filter stage and a balun is disposed between the balanced port and the unbalanced port. The balun and the filter stage are formed on the substrate.

Abstract: A duplexer comprising a transmit resonator device and a receive resonator device for filtering transmit and receive signals. The resonator device has a first BAW resonator for generating an acoustic wave signal from an input electric signal, a first acoustic delay for delaying the acoustic wave signal, and an intermediate BAW resonator for receiving the delayed acoustic wave signal at one end and converting the delayed acoustic wave signal to an electric signal. Through electrical coupling, the electric signal also appears at another end of the intermediate BAW resonator for generating a further acoustic wave signal at the other end. The resonator further comprises a second delay for delaying the further acoustic wave signal, and a second BAW resonator for producing an output electric signal from the delayed further acoustic wave signal. The duplexer can be used in a transceiver in a mobile phone.

Abstract: A bulk acoustic wave (BAW) filter (40) is fabricated from thin film bulk acoustic wave resonators and a method eliminates unwanted side passbands. This BAW filter comprises a substrate (14) a resonator section (11) and an acoustic mirror section (12). Further it comprises a detuning component (31) positioned in the resonator section (11) to provide precise passband characteristics and an additional detuning component (41) in the acoustic mirror section (12) to suppress unwanted side-passband characteristics.

Abstract: A filter device comprises a substrate having a top surface and a bottom surface, and at least one acoustic wave situated on the top surface of the substrate, wherein the bottom surface of the substrate is roughened to reduce the reflection of an acoustic wave back to the acoustic wave filter. The effect achieved by the roughening of the bottom surface of the substrate that an acoustic wave which is generated by the acoustic wave filter and reaches the bottom surface of the substrate, is basically scattered so the acoustic wave that is actually reflected back to the acoustic wave device is reduced which, in turn, improves the performance characteristics of the acoustic wave filter.

Abstract: A BAW resonator includes a piezoelectric layer, a first electrode, a second electrode, a substrate, and an acoustic reflector disposed between the substrate and the second electrode. The acoustic reflector has a plurality of layers. A performance of the acoustic reflector is determined by its reflectivity for a longitudinal wave existing in the BAW resonator at the resonance frequency of the BAW resonator and by its reflectivity for a shear wave existing in the BAW resonator at the resonance frequency of the BAW resonator. The layers of the acoustic reflector and layers disposed between the acoustic reflector and the piezoelectric layer are selected, with reference to their number, material, and thickness, such that the transmissivity for the longitudinal wave and the transmissivity for the shear wave in the area of the resonance frequency is smaller than ?10 dB.

Abstract: The invention relates to bulk acoustic wave filters including at least two bulk acoustic wave resonators. Each of these resonators includes at least one first electrode, a piezoelectric layer, and a second electrode. At least two of the bulk acoustic wave resonators have effective resonator surfaces which differ in their surface form and/or surface content. The inventive design of the bulk acoustic wave resonators enables optimal suppression of interference modes without influencing the impedance level of the filter.

Abstract: In a method for producing a cover for a region of a substrate, first a frame structure is produced in the region of the substrate, and then a cap structure is attached to the frame structure so that the region under the cap structure is covered. Thus, sensitive devices may be protected easily and at low cost from external influences and particularly from a casting material for casting the entire packaged device, which results when a diced chip is cast.

Abstract: A semiconductor component is provided having a layer sequence for conversion of acoustic to thermal signals and electrical voltage changes to one another, as well as a process for its production. The layer sequence has a lower electrode, an upper electrode and a layer which is arranged between them and is piezoelectrical or pyroelectrical. An auxiliary layer is arranged between the lower electrode and the layer and is used for homogeneously oriented growth of the layer during the production process. The auxiliary layer preferably consists essentially of amorphous silicon, amorphous silicon oxide or amorphous silicon nitride.

Abstract: In a method for manufacturing a piezoelectric oscillating circuit in thin film technology, wherein the oscillating circuit includes a predetermined natural frequency and a plurality of layers, first of all at least a first layer of the piezoelectric oscillating circuit is generated. Subsequently, by processing the first layer a frequency correction is performed. Subsequently, at least a second layer of the piezoelectric oscillating circuit is generated and processed for performing a second frequency correction.

Abstract: A resonator device includes a piezoelectric resonator having a detuning layer sequence arranged on the piezoelectric resonator. The detuning layer sequence includes at least a first layer having a high acoustic impedance and a second layer having a low acoustic impedance.

Abstract: In a method for generating a protective cover for a device, where a substrate is provided, which comprises the device, first, a sacrificial pattern is generated on the substrate. The sacrificial pattern covers at least an area of the substrate, which comprises the device. Then, a polymer layer is deposited, which comprises at least on sacrificial pattern. Then, an opening will be formed in the polymer layer to expose a portion of the sacrificial pattern. Then, the sacrificial pattern will be removed and the formed opening in the polymer layer is closed.