A circuit includes a localized metal-insulator-metal (MIM) capacitor array in a radio frequency (RF) front end circuit, which is integrated on a first die, and includes a localized common shared ground node within the localized MIM capacitor array, a plurality of inductors, and a plurality of RF filters. Each of the plurality of RF filters includes a plurality of passive resonant frequency circuits, and each of the plurality of passive resonant frequency circuits is implemented utilizing one or more MIM capacitors in the localized MIM capacitor array, and one or more of the plurality of inductors. The plurality of inductors may be arranged at a periphery of the localized MIM capacitor array on the first die or integrated on a second die, which is coupled to the first die. Each of the MIM capacitors in the localized MIM capacitor array has a different capacitance value.

A radio frequency (RF) receiver, which has an RF filter and impedance matching circuit and an RF low noise amplifier (LNA), is disclosed. The RF filter and impedance matching circuit includes a first passive RF acoustic resonator; provides an RF bandpass filter having an RF receive band based on the first passive RF acoustic resonator; and presents an input impedance at an RF input and an output impedance at an RF output, such that a ratio of the output impedance to the input impedance is greater than 40. The RF LNA is coupled to the RF output.

RF communications circuitry, which includes a first tunable RF filter and a second tunable RF filter, is disclosed. The first tunable RF filter is coupled to the second tunable RF filter. The RF communications circuitry operates in one of a first operating mode and a second operating mode. During the first operating mode, the second tunable RF filter receives and filters an upstream RF signal to provide a filtered RF signal. Further, during the first operating mode, the first tunable RF filter augments a frequency response of the second tunable RF filter.

RF communications circuitry, which includes a first RF filter structure and control circuitry, is disclosed. The first RF filter structure includes a pair of weakly coupled resonators and a first tunable RF filter. The control circuitry provides a first filter control signal. The first tunable RF filter receives and filters an upstream RF signal to provide a first filtered RF signal, such that a center frequency of the first tunable RF filter is based on the first filter control signal.

A wide bandwidth multiplexer (MUX) is provided that performs carrier aggregation. The MUX combines at least a first LC filter that acts as a low band filter, at least a first composite filter that acts as a middle band filter, and at least one other LC or composite filter that acts as a high band filter. The wide bandwidth MUX has low insertion loss and provides sufficient attenuation at adjacent edges of adjacent pass bands to prevent overlap between adjacent pass bands.

A very wide bandwidth composite band pass filter with steep roll-off of a corresponding passband includes a band pass filter and a high-Q acoustic resonator. The band pass filter has a corresponding passband with a very wide bandwidth and a passband roll-off. The high-Q acoustic filter has a corresponding stopband with a roll-off steeper than the passband roll-off, the high-Q acoustic filter being connected in parallel with the band pass filter such that a portion of the stopband is within the passband of the band pass filter, forming a combined passband. A frequency range of the combined passband is approximately the same as a frequency range of the passband of the band pass filter, and a combined roll-off of the combined passband is steeper on one side than the passband roll-off of the band pass filter.

An LC parallel resonator includes a plurality of dielectric layers stacked on top of one another, a capacitor electrode, and an inductor electrode. The inductor electrode defines a loop including a connection point, as a start point, connected to the capacitor electrode. The inductor electrode includes a first line electrode, first via electrodes, and second via electrodes. The first line electrode extends in a direction perpendicular or substantially perpendicular to a stacking direction of the dielectric layers. The first via electrodes arranged in parallel or substantially in parallel with one another extend in the stacking direction of the dielectric layers, and connect the capacitor electrode to the first line electrode. The second via electrodes arranged in parallel or substantially in parallel with one another extend in the stacking direction of the dielectric layers and are connected to the first line electrode.

There is provided a filter for receiving a rectangular or stepped source voltage to be filtered and for providing an output voltage, the filter including means arranged to determine the output voltage in dependence on the frequency components of the source voltage within the filter passband, and independent of output current drawn.

A front-end circuit with a tunable filter is disclosed. In an embodiment, the front end circuit includes a first signal path connected to an antenna connection, a first filter arranged in the first signal path, wherein the first filter is tunable within a first frequency range, and an extra signal path and a first fixed filter arranged therein, wherein the first fixed filter has a passband for an extra frequency band, wherein the first fixed filter is not tunable, and wherein the extra frequency band is arranged outside or inside the first frequency range. The front end circuit further includes a narrowband antenna tuner configured to be set to a respective tunable frequency range, wherein the narrowband antenna tuner is arranged between the first filter, the first fixed filter and the antenna connection in the first and second signal paths.

A tunable duplexer is specified is disclosed. In an embodiment, the duplexer includes a transmission port, a reception port, a common port and a core having a first inductive element and a second inductive element. The duplexer further includes a first signal path electrically connecting the transmission port to the core, a second signal path electrically connecting the reception port to the core and a third signal path electrically connecting the common port to the core. A first tunable capacitive element electrically connects the first signal path to ground and a second tunable capacitive element electrically connects the second signal path to ground, wherein the first inductive element and the second inductive element are inductively and conductively coupled to one another.