Improved surface acoustic wave structures (or elements) that can be used to realize any of a wide variety of dispersive or non-dispersive transversal SAW filters that are distinct from prior known means for producing such filters are disclosed. The devices and structures may include stepped acoustic wave delay modification elements that can be used to implement transversal filter impulse response functions in a manner analogous to the use of interdigital transducers. The structures disclosed are of particular usefulness to implement SAW devices at high frequencies where normal photolithographic resolution would prove limiting. Aspects and embodiments of the present invention would be useful to produce SAW devices for use in a wide variety of applications, including as components in cell phones, in radar and other communications and electronic systems, and as wired or wireless sensors or sensor-tags.

An electroacoustic filter has improved low-pass characteristics. The filter includes a first electroacoustic converter, an electroacoustic element and a grid structure between the converter and the element. The grid structure is acoustically active in one frequency range that lies above the acoustically active frequency range of the first electroacoustic converter.

A filter working with surface acoustic waves comprises a piezoelectric substrate (SU), a first transducer (IDT1) arranged in the acoustic track coupled to an input, having a first mean finger period (pi) assigned to a center frequency of a pass band of the filter and a second transducer (IDT2) arranged in the acoustic track coupled to an output, having the same first mean finger period (p1), and a reflector arranged between first and second transducer having a second mean finger period (p2) assigned to a stop band frequency different from the center frequency. Further, a new type of very broad bandwidth filters with small insertion loss and high return loss and high rejection are given that use a substrate that can propagate a PSAW and comprises fan shaped transducers.

In a filter device, a transversal elastic wave filter, which defines a delay element, is connected in parallel with a band pass filter. The transversal elastic wave filter has the same amplitude characteristic as and the opposite phase to the band pass filter at a desired frequency inside an attenuation range of the band pass filter. When a wavelength determined by an electrode finger period of IDTs and is denoted by , the distance between the first IDT and the second IDT of the elastic wave filter is about 12 or less.

Acoustic wave device is disclosed. the acoustic wave device can include a piezoelectric layer and an interdigital transducer electrode over the piezoelectric layer. The interdigital transducer electrode having a non-zero tilt angle. The non-zero tilt angle can between 5 to 15. The interdigital transducer electrode is configured to shift stopband of the acoustic wave device and to reduce a slanted stopband.

A surface acoustic wave device can have a piezoelectric layer and at least one interdigital transducer electrode thereon with a trapezoidal shape. This can be useful to fill dead space or voids between nonparallel elements on the layer. For example, an array with ranks of slanted interdigital transducer electrodes may not be aligned with non-slanted elements (e.g., a surface acoustic wave filter). This can leave voids or openings with unused portions of the piezoelectric layer. Trapezoidal elements such as those described here can solve this problem and help suppress transverse modes.