A method and apparatus for modifying or controlling a resonator connected to a signal loop having an input, an output, and a closed loop frequency response. The signal loop has a primary resonator having a primary frequency response. There is at least one adjustable resonator having an adjustable frequency and a secondary Q-factor. An adjustable scaling block applies a gain factor. A controller is connected to the at least one adjustable resonator and the adjustable scaling block. The controller has instructions to adjust the closed loop frequency response toward a desired closed loop frequency response by controlling the adjustable frequency of the at least one adjustable resonator and the gain factor of the adjustable scaling block.

A clock oscillator, a clock oscillator production method and use method, and a chip including the clock oscillator are provided. The clock oscillator includes a resonator, a shock-absorbing material layer, and a base, and at least a part of the shock-absorbing material layer is located between the resonator and the base. In the clock oscillator, the shock-absorbing material layer is added between the resonator and the base, and the shock-absorbing material layer can effectively prevent a mechanical wave from being conducted between the base and the resonator, so that the resonator is protected from external vibration. This can ensure, when there is external vibration, that an output frequency of the resonator is not deteriorated and improve shock absorption performance of the clock oscillator.

A filter module includes a filter provided on a path connecting an input/output terminal and an input/output terminal, a filter provided on a path connecting an input/output terminal and an input/output terminal, a switch that switches between electrical connection and electrical disconnection between a wire connected to the input/output terminal and a ground, and a switch that switches between electrical connection and electrical disconnection between a wire connected to the input/output terminal and the ground. When the wire and the ground are electrically connected by the switch, the wire and the ground are electrically disconnected by the switch, and when the wire and the ground are electrically connected by the switch, the wire and the ground are electrically disconnected by the switch.

A radio frequency filter includes at least a first sub-filter and a second sub-filter connected in parallel between a first port and a second port. Each of the sub-filters has a piezoelectric plate having front and back surfaces, the back surface attached to a substrate, and portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on the front surface of the plate, the conductor pattern includes interdigital transducers (IDTs) of a respective plurality of resonators, with interleaved fingers of each IDT disposed on a respective diaphragm of the plurality of diaphragms. A thickness of the portions of the piezoelectric plate of the first sub-filter is different from a thickness of the portions of the piezoelectric plate of the second sub-filter.

In certain aspects, a chip includes an acoustic resonator, and a mirror under the acoustic resonator. The mirror includes a first plurality of porous silicon layers, and a second plurality of porous silicon layers, wherein the mirror alternates between the first plurality of porous silicon layers and the second plurality of porous silicon layers, and each of the first plurality of porous silicon layers has a higher porosity than each of the second plurality of porous silicon layers.

Aspects of the disclosure relate to wireless communication, and high-frequency filters with resonators configured to systematically modify phase characteristics of an antenna reflection coefficient. One example is a wireless communication apparatus for a multi-band system comprising a frequency band filter circuit having a filter passband that includes a first band of the multi-band system. The frequency band filter circuit comprises a plurality of resonators coupled between an antenna port and a signal port and a resonant structure electrically coupled to the plurality of resonators. The resonant structure has a resonance outside of the first band and a second band of the multi-band system, the resonance being closer to the second band than to the first band.

A combination filter comprises a notch filter formed of acoustic wave resonators and a cavity filter electrically in series with the notch filter to provide for the combination filter to operate at higher powers and frequencies.

Aspects of the disclosure relate to wireless communication, and high-frequency filters with resonators configured to systematically modify phase characteristics of an antenna reflection coefficient. One example is a wireless communication apparatus for a multi-band system comprising a frequency band filter circuit having a filter passband that includes a first band of the multi-band system. The frequency band filter circuit comprises a plurality of resonators coupled between an antenna port and a signal port and a resonant structure electrically coupled to the plurality of resonators. The resonant structure has a resonance outside of the first band and a second band of the multi-band system, the resonance being closer to the second band than to the first band.

A radio frequency filter includes at least a first sub-filter and a second sub-filter connected in parallel between a first port and a second port. Each of the sub-filters has a piezoelectric plate having front and back surfaces, the back surface attached to a substrate, and portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on the front surface of the plate, the conductor pattern includes interdigital transducers (IDTs) of a respective plurality of resonators, with interleaved fingers of each IDT disposed on a respective diaphragm of the plurality of diaphragms. A thickness of the portions of the piezoelectric plate of the first sub-filter is different from a thickness of the portions of the piezoelectric plate of the second sub-filter.

A method and apparatus for modifying or controlling a resonator connected to a signal loop having an input (18828), an output (18822), and a closed loop frequency response. The signal loop has a primary resonator (18810) having a primary frequency response. There is at least one adjustable resonator (18812) having an adjustable frequency (f) and a secondary Q-factor. An adjustable scaling block (18824) applies a gain factor (g). A controller is connected to the at least one adjustable resonator (18812) and the adjustable scaling block (18824). The controller has instructions to adjust the closed loop frequency response toward a desired closed loop frequency response by controlling the adjustable frequency (f) of the at least one adjustable resonator (18812) and the gain factor (g) of the adjustable scaling block (18824).