An acoustoelectric amplifier and a number of corresponding devices are disclosed, along with methods for making the same. The acoustoelectric amplifier employs wafer-scale bonding to heterogeneously integrate an epitaxial III-V semiconductor stack and a piezoelectric layer. To increase the acoustic gain with low power dissipation, the electromechanical coupling coefficient (k.sup.2) of the piezoelectric layer should be high to increase the acoustoelectric interaction strength. The semiconductor mobility should be high to reduce the voltage required to increase the carrier drift velocity. The conductivity-thickness product should be low to prevent screening of the acoustoelectric interaction. The acoustoelectric amplifier or its corresponding material structure may be used to form circulators, isolators, oscillators, mixers, and correlators, while interconnecting waveguides may be formed of the piezoelectric layer or the semiconductor stack. An exemplary piezoelectric layer is formed of LiNbO.sub.3, while an exemplary semiconductor stack is formed of InGaAs/InP.

The present invention discloses a type of ultra-wide band SAW filter which comprises a first SAW resonator group and a second SAW resonator group that are connected to form a ladder structure. Each SAW resonator in the said first SAW resonator group has the same film thickness; each SAW resonator in the said second SAW resonator group has the same film thickness; the film thickness of each SAW resonator in the said first SAW resonator group is the same as or different from the film thickness of each SAW resonator in the said second SAW resonator group. The SAW filter according to the present invention can realize the pass-band non-parasitic mode response and is a high-performance ultra-wide band filter with a bandwidth of 6-20% of the center frequency and an insertion loss of less than 2 dB, and the present invention features small size, low cost and a broad application prospect in the field of military and civilian communications equipment.

In an arrangement having a DMS filter, it is provided to symmetrically divide at least one of the transducers (W) of the DMS filter (DMS) into two sub-transducers (T,T) electrically connected in parallel and to shift them apart from each other by an amount of at least a half wavelength. This results in the signals of the two sub-transducers canceling each other out at a frequency in a stopband and thereby generating an attenuation pole in the upper blocking region.

An acoustic wave element of the present invention includes a substrate; and an IDT electrode on an upper surface of the substrate, including a first bus bar, a second bus bar arranged with a space in a first direction from the first bus bar, a plurality of first electrode fingers connected to the first bus bar, a plurality of second electrode fingers connected to the second bus bar, and a second dummy electrode finger facing a tip end of one of the first electrode fingers through a gap. In at least one of the second electrode fingers, a width in a region on the side closer to the second bus bar than a first virtual line connecting the tip ends of the plurality of first electrode fingers is wider than a width in a region on the side closer to the first bus bar than the first virtual line.

A SAW filter arrangement (FA) with a large bandwidth is specified, wherein a first filter (F1) and a second filter (F2) are connected in parallel between a first node (K1) and a second node (K2). The first filter (F1) and the second filter (F2) are both SAW filter configurations that are configured as DMS filters and both comprise two DMS tracks each, connected in series (S11, S12; S21, S22). The two filters (F1, F2) have different center frequencies and create a common passband together. The filter arrangement may comprise a serial resonator (RS) and shunting coils (L1, L2).