RF communications circuitry, which includes a first tunable RF filter and a first RF low noise amplifier (LNA) is disclosed. The first tunable RF filter includes a pair of weakly coupled resonators, and receives and filters a first upstream RF signal to provide a first filtered RF signal. The first RF LNA is coupled to the first tunable RF filter, and receives and amplifies an RF input signal to provide an RF output signal.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

RF communications circuitry includes an RF filter structure, which includes a group of resonators, a group of cross-coupling capacitive structures, and a group of egress/ingress capacitive structures, is disclosed. Each of the group of cross-coupling capacitive structures is coupled between two of the group of resonators. A first portion of the group of egress/ingress capacitive structures is coupled between a first connection node and the group of resonators. A second portion of the group of egress/ingress capacitive structures is coupled between a second connection node and the group of resonators.

Certain aspects of the present disclosure provide methods and apparatus for calibrating a tunable active filter. One example apparatus is a filter circuit that generally includes a tunable active filter comprising at least one amplifier and a first feedback path coupled between an input and an output of the at least one amplifier, the first feedback path comprising at least one switch; and an amplitude limiter coupled to the tunable active filter and comprising at least one transistor disposed in a second feedback path coupled between the input and the output of the at least one amplifier.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

Embodiments of an apparatus that includes a substrate and an inductor residing in the substrate are disclosed. In one embodiment, the inductor is formed as a conductive path that extends from a first terminal to a second terminal. The conductive path has a shape corresponding to a two-dimensional (2D) lobe laid over a three-dimensional (3D) volume. Since the shape of the conductive path corresponds to the 2D lobe laid over a 3D volume, the magnetic field generated by the inductor has magnetic field lines that are predominately destructive outside the inductor and magnetic field lines that are predominately constructive inside the inductor. In this manner, the inductor can maintain a high quality (Q) factor while being placed close to other components.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

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.