A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction The surface acoustic wave apparatus has at least one interdigital transducer; a region with the plurality of interleaved comb-shaped electrodes is formed with two regions which are a first overlapping region and a second overlapping region with overlapping-lengths weighted along a propagation direction of a surface acoustic wave; the first overlapping region and the second overlapping region are in contact or overlapped in a direction vertical to the propagation direction of the surface acoustic wave; and in either the first or the second overlapping region, an overlapping-length weighting envelope curve has at least two or more changing points in the propagation direction of the surface acoustic wave

Surface acoustic wave apparatus

The filter can be operated either symmetrically or in an unbalanced mode, and has at least two serial or parallel coupled filter units (F1,F2) on a piezo electrical substrate. Each filter unit has at least two acoustic transducers, between two reflectors (R), coupled to the inputs and outputs (IN,OUT) of the filter. At least two filter units, with at least one reflector between the units, are arranged side-by-side in a first track inline arrangement. The apertures of the filters are vertically arranged to the propagation direction of the acoustic surface wave, and are arranged on the same level. Preferably, the inputs of the two filter units of the first track, and the outputs of the filter units, are coupled in parallel.

Dual mode surface wave filter for high frequency applications

It consists of several channels (V1, V2) in parallel, which exhibit an inter-transducer gap difference (2 1 -4 1 ; 2 2 -4 2 ) equal to an even multiple of the half-wavelength (λ) at the central frequency, from one channel to the next, so as to cancel the delay line transfer function which corresponds to the direct path between transducers.

Surface wave filter filtering delay transfer function

An acoustic wave device (100) which utilities multiple localized reflections of acoustic wave for achieving an infinite impulse response while maintaining high tolerance for dampening effects, is disclosed. The device utilized a plurality of electromechanically significant electrodes (110, 120, 130) disposed on most of the active surface. A plurality of sensors utilizing the disclosed acoustic wave mode device are also described.

Multi-reflective acoustic wave device

A SAW filter is configured so that a resonator-type filter portion, in which a plurality of SAW resonators are connected in series and in parallel, and a 3-electrode type serially coupled filter portion, in which three IDTs for inputting and outputting signals are interposed between reflectors, are serially connected on one and the same substrate. The design parameters of the respective SAW resonators are adjusted so that the impedances of respective sides of the filter portions, when viewed from the node of the resonator-type SAW filter portion and the 3-electrode type serially coupled SAW filter portion, substantially have a complex conjugate relationship with each other in the pass frequency band.

Surface acoustic wave filter with different filter portions satisfying complex conjugate relationship of impedances

Digital structures of a surface wave filter are manufactured in a photolithographic method with a lift-off or with an etching technique. The surface wave filter comprises at least one resonator structure, this resonator structure having auxiliary coatings of the substrate surface allocated to it. These auxiliary coatings are continuations of existing, neighboring pads which compensate during an exposure step associated with manufacture of the digital structures.

Filter functioning with acoustic waves

A surface-wave resonator filter having at least two reflector structures and at least one interdigital transducer. At least a portion of one of the reflector structures has interruptions in the metallization strips thereof to define subsections of the metallization strip. Connecting metallizations are provided parallel to the wave propagation direction x between neighboring sub-sections of neighboring sub-divided metallization strips to electrically connect the neighboring sub-sections such that no two sub-sections of the same sub-divided metallization strip are electrically connected.

Surface-wave resonator structure having metallization strips interrupted in sub-sections in reflector fingers

An interdigital converter of a surface acoustic wave filter is internally protected against electrostatic discharges. The protection is provided by a resistor which is connected in parallel to the interdigital converter.

Component working with surface acoustic waves

A surface wave filter with an input transducer and an output transducer. The input and output transducers have finger weightings such that a finger-overlap profile of the input/output transducer repeats in multiple fashion in the output/input transducer.

Electrical filter with acoustic waves

A surface wave filter (1, 11, 21, 31, 41) having a shielding structure (13, 23, 33, 43, 53) arranged between the inter-digital, asymmetrically operating structures (2, 3), which encompasses two such sub-structures (14, 24, 34, 44, 44a) and/or (15, 25, 35, 45, 35a), which are individually connected with the finger structures of the adjacent transducer structure (2 and/or 3) that are at reference ground potential.

Peter Zibis

Papers

Filter functioning with acoustic waves

Surface-wave resonator structure having metallization strips interrupted in sub-sections in reflector fingers

Component working with surface acoustic waves

Electrical filter with acoustic waves

Electric filter employing acoustic waves