A system for a wireless communication infrastructure using single crystal devices. The wireless system can include a controller coupled to a power source, a signal processing module, and a plurality of transceiver modules. Each of the transceiver modules includes a transmit module configured on a transmit path and a receive module configured on a receive path. The transmit modules each include at least a transmit filter having one or more filter devices, while the receive modules each include at least a receive filter. Each of these filter devices includes a single crystal acoustic resonator device formed with a thin film transfer process with at least a first electrode material, a single crystal material, and a second electrode material. Wireless infrastructures using the present single crystal technology perform better in high power density applications, enable higher out of band rejection (OOBR), and achieve higher linearity as well.

An acoustic wave resonator includes: a substrate; a resonating portion formed on a first surface of the substrate; a metal pad connected to the resonating portion through a via hole formed in the substrate; and a protective layer disposed on a second surface of the substrate and including a plurality of layers, wherein the plurality of layers includes an internal protective layer directly in contact with the second surface of the substrate and formed of an insulating material including an adhesion that is stronger than an adhesion of other layers, among the plurality of layers.

A radio-frequency front end circuit includes an input terminal, output terminals, a first filter, a third filter, and a matching inductor. The first filter is connected between the input terminal and the output terminal and allows a first communication signal in a low band to pass. The first filter is defined by an elastic wave filter. The third filter is connected between the input terminal and the output terminal and allows a third communication signal in a high band to pass. The third filter is defined by a high pass filter including an inductor and capacitors. The matching inductor is connected between the filter and the input terminal.

An elastic wave device includes a piezoelectric substrate and an interdigital transducer (IDT) electrode. The IDT electrode is disposed on the piezoelectric substrate and includes an electrode layer including molybdenum as a main component. The duty ratio of the IDT electrode is about 0.3 to about 0.48.

There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The interleaved fingers of the IDT are substantially molybdenum. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. A thickness of the interleaved fingers of the IDT is between 0.25 times and 2.5 times a thickness of the piezoelectric plate.

A front end module includes a base filter configured to operate as a bandpass filter passing a pass band of an input radio frequency signal; a switch connected to the base filter, and a first notch filter and a second notch filter selectively connected to the base filter through the switch, wherein a stop band of the first notch filter and a stop band of the second notch filter overlap the pass band of the base filter in a band equal to or higher than a center frequency of the pass band of the base filter.

An electronic device package includes a lower surface for conducting electronic signals, a first solder bond pad having a first size disposed on the lower surface, and a plurality of second solder bond pads having second sizes smaller than the first size disposed on the lower surface and surrounding the first solder bond pad.

Various embodiments may relate to an acoustic resonator. The acoustic resonator may include a piezoelectric layer. The acoustic resonator may also include a first electrode in contact with a first surface of the piezoelectric layer. The acoustic resonator may further include a plurality of dielectric structures in contact with the first surface of the piezoelectric layer. The acoustic resonator may additionally include a second electrode in contact with a second surface of the piezoelectric layer opposite the first surface. The first electrode may include a plurality of electrode structures. A dielectric structure of the plurality of dielectric structures may be in contact with a pair of neighboring electrode structures of the plurality of electrode structures.

A multiplexer includes a first filter on a first path connecting a common terminal and a first terminal and defined by a band pass filter, a low pass filter, or a high pass filter, and a second resonator on a second path connecting the common terminal and a second terminal and defined by a band elimination filter including at least one elastic wave resonator. A pass band of the first filter and an attenuation band of the second filter overlap with each other, and a ripple of a first resonator closest to the common terminal is generated only outside pass bands of the first filter and the second filter.

A filter device provides a wideband passband of a communication device for a RF signal. The filter device includes a first filter circuit in parallel with a second filter circuit. The first filter circuit includes a first notch filter, and has a first notch. The second filter circuit includes a second notch filter in series with a reversal circuit for phase shifting the RF signal filtered by the second notch filter, the second filter circuit having a second notch. The first and second filter circuits form a band pass filter having a passband between a lower cutoff frequency defined by the second notch and an upper cutoff frequency defined by the first notch. The band pass filter provides low insertion loss in the passband, and high insertion loss in an adjacent lower stopband below the lower cutoff frequency and in an adjacent upper stopband above the upper cutoff frequency.