摘要:
In a tester for a surface acoustic wave device used as a filter for high frequency bands in the field of mobile communications, the tester includes: an electron gun generating an electron beam to be first electrons; a condenser lens for converging the electron beam on a substrate; an electron beam scanning portion for scanning the electron beam on the substrate; a secondary electron detector detecting second electrons generating from the substrate by irradiated first electrons; a substrate holder holding the substrate; and a conductive grounding tool which can contact the metal film. The grounding tool includes a contacting head. The grounding tool includes: a contacting head that can contact the grounding tool and the metal film; an arm portion arranged at the end of the contacting head; a shaft arranged at the other end of the contacting head, and rotating the arm portion. The substrate has a two-layer structure, which includes: a circular piezo-electric substrate including lithium tantalate (LiTaO3); and a metal film including aluminum (Al) formed on the piezo-electric substrate.
摘要:
A passive filter arrangement and a method of providing such a filter is described. The frequency response of the filter arrangement is substantially the same as the frequency response of a first filter of an order having a first value, the frequency response of the first filter being representable by a first set of one or more poles and/or one or more zeros. Descriptions of a plurality of second filters are generated, each second filter having an order lower than the order of the first value, each second filter having a frequency response representable by a one or more poles and/or one or more zeros, the one or more poles and/or one or more zeros of each lower order filter being a subset of the first set. The lower order filters are cascaded.
摘要:
There is provided a piezoelectric substrate (12) in the form of a rectangular plate in which a Rayleigh wave is propagated and an IDT (13) and a reflector (14) provided by forming interdigital electrodes on the piezoelectric substrate. At least an end face on a shorter side of the piezoelectric substrate on a top side thereof is formed as a vertical smooth surface that is substantially in parallel with a conductor strip at an end of the reflector (14) in the position of an imaginary node (J) of a stress wave (T) exiting the conductor strip, there by providing a reflecting end face (15, 16) for reflecting the stress wave.
摘要:
This invention comprises in combination a body of piezoelectric material, means for propagating an acoustic wave in a first mode, means for converting a portion of the acoustic wave energy into an acoustic wave in a second mode, a resonant structure in which the acoustic wave energy in the second mode is resonant, means for reconverting the acoustic wave energy in the second mode into surface acoustic wave energy in the first mode, means for providing a predetermined phase shift of the reconverted acoustic wave energy relative to the original propagated acoustic wave energy, and means for recovering the combined acoustic wave energy of the original and phase shift reconverted acoustic wave energies as an electric output signal.
摘要:
Methods to design band-pass acoustic wave microwave filters are disclosed. A performance metric related to an input impedance of a baseline filter design is calculated, the baseline filter design including a plurality of series surface acoustic wave resonators and a plurality of shunt surface acoustic wave resonators, each surface acoustic wave resonator having a respective resonant frequency. One or more alternative filter designs is established, each alternative filter design derived from the baseline filter design by reordering the resonant frequencies of two or more of the plurality of series surface acoustic wave resonators and/or two or more of the plurality of shunt surface acoustic wave resonators. A respective performance metric related to an input impedance of each alternative filter designs is calculated. A final filter design is selected from among the baseline filter design and the alternative filter designs based on the respective performance metrics.
摘要:
Methods of designing band-pass filters are disclosed. A baseline filter design is established, the baseline filter design including a plurality of surface acoustic wave resonators having respective resonant frequencies, the surface acoustic wave resonators organized by resonant frequency into two or more groups. One or more alternative filter designs are established, each alternative filter design derived from the baseline filter design by reordering the resonant frequencies of two or more surface acoustic wave resonators within at least one of the two or more groups. A respective performance metric related to input impedance over a pass band is calculated for each of the baseline filter design and the alternative filter designs. A final filter design is selected from the baseline filter design and the alternative filter designs based on the respective performance metrics.
摘要:
A method for optimizing impedance of a connecting element between a first component and a second component of a high-frequency apparatus. The first component and the second component have at least two level states, wherein the connecting element has an input impedance and an output impedance. The first component has respective impedances in each of the at least two level states, wherein the second component has respective impedances in each of the at least two level states. The method comprising the steps as follows: determining a respective magnitude of a difference of the first component between the complex conjugated input impedance and a respective impedance of the first component, determining a respective magnitude of a difference of the second component between the complex conjugated output impedance and a respective impedance of the second component, and simultaneously minimizing the respective magnitudes of the first component and second component relative to the in- and output impedances of the connecting element.
摘要:
Multistage matching networks and analytical frameworks for improving and/or optimizingthe networks is provided. In one example, a framework relaxes the resistive constraint on the input and load impedances of the stages of a multistage matching network and allows them to be complex. Based on this framework, the design of multistage matching networks can be improved or optimized, such as using a method of Lagrange multipliers. A design optimization approach, for example, can be used to predict an optimum distribution of gains and impedance characteristics among the stages of a multistage matching network. The efficiency of matching networks designed using this example approach is compared with a conventional design approach, and it is shown that significant efficiency improvements are possible.
摘要:
A filter may be constructed from multiple acoustic elements in parallel. A filtering method may comprise passing a signal to be filtered through such parallel acoustic elements. Such filtering may be applicable to communication devices.
摘要:
Methods of designing band-pass filters are disclosed. A baseline filter design is established, the baseline filter design including a plurality of surface acoustic wave resonators having respective resonant frequencies, the surface acoustic wave resonators organized by resonant frequency into two or more groups. One or more alternative filter designs are established, each alternative filter design derived from the baseline filter design by reordering the resonant frequencies of two or more surface acoustic wave resonators within at least one of the two or more groups. A respective performance metric related to input impedance over a pass band is calculated for each of the baseline filter design and the alternative filter designs. A final filter design is selected from the baseline filter design and the alternative filter designs based on the respective performance metrics.