Disclosed herein is a common mode filter that includes: a first conductor layer including a first coil pattern, a first connection pattern, and a first lead-out pattern connecting the first coil pattern and the first connection pattern; and a second conductor layer including a second coil pattern, a second connection pattern, and a second lead-out pattern connecting the second coil pattern and the second connection pattern. The extending direction of the first section of the first lead-out pattern and an extending direction of the second section of the second lead-out pattern are opposed to each other. The first section is longer than the second section. The second coil pattern is larger in diameter than the first coil pattern.

A signal processing circuit includes an input buffer circuit and a direct-(DC) voltage detector circuit. The input buffer circuit is coupled to a pin. The pin is configured to receive an input signal. The DC voltage detector circuit is coupled to the pin and the input buffer circuit. The DC voltage detector circuit is configured to detect the input signal to generate a mode signal and generate a bias of the input buffer circuit according to the mode signal.

An exemplary tunable circuit includes an inductor coupled to a node and a first capacitor coupled to the node. The tunable circuit also includes a variable capacitor coupled to the node, such that a total capacitance of the tunable circuit depends on a fixed capacitance of the first capacitor and a variable capacitance of the variable capacitor. In an example, the inductor and the first capacitor are both included in a passive device and the variable capacitor is in a semiconductor device. The variable capacitor allows the total capacitance to be modified for the purpose of, for example, calibrating the capacitance to account for manufacturing variations, and/or adjusting to a frequency range of operation used by wireless devices in a region of the world. The first capacitor may be a higher quality capacitor providing a larger portion of the total capacitance than the variable capacitor.

An exemplary tunable circuit includes an inductor coupled to a node and a first capacitor coupled to the node. The tunable circuit also includes a variable capacitor coupled to the node, such that a total capacitance of the tunable circuit depends on a fixed capacitance of the first capacitor and a variable capacitance of the variable capacitor. In an example, the inductor and the first capacitor are both included in a passive device and the variable capacitor is in a semiconductor device. The variable capacitor allows the total capacitance to be modified for the purpose of, for example, calibrating the capacitance to account for manufacturing variations, and/or adjusting to a frequency range of operation used by wireless devices in a region of the world. The first capacitor may be a higher quality capacitor providing a larger portion of the total capacitance than the variable capacitor.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

Disclosed is a gallium arsenide (GaAs) enabled tunable filter for, e.g., 6 GHz Wi-Fi RF Frontend, with integrated high-performance varactors, metal-insulator-metal (MIM) capacitors, and 3D solenoid inductors. The tunable filter comprises a hyper-abrupt variable capacitor (varactor) high capacitance tuning ratio. The tunable filter also comprises a GaAs substrate in which through-GaAs-vias (TGV) are formed. The varactor along with the MIM capacitors and the 3D inductors is formed in an upper conductive structure on upper surface of the GaAs substrate. Lower conductive structure comprising lower conductors is formed on lower surface of the GaAs substrate. Electrical coupling between the lower and upper conductive structures is provided by the TGVs. The tunable filter can be integrated with radio frequency front end (RFFE) devices.

Systems, devices, and methods for adjusting tuning settings of tunable components, such as tunable capacitors, can be configured for calibrating a tunable component. Specifically, the systems, devices and methods can measure a device response for one or more inputs to a tunable component, store a calibration code in a non-volatile memory that characterizes the device response of the tunable component, and adjust a tuning setting of the tunable component based on the calibration code to achieve a desired response of the tunable component.

A high-order filter with a capacitive inner tapping technique is disclosed. The filter includes an inductor and a first resonant circuit including a first portion of the inductor and a first capacitor. The first resonant circuit is configured to attenuate first frequency components of an input signal above a cutoff frequency to generate a filtered signal. The filter further includes a second resonant circuit coupled in parallel with the first resonant circuit and including the first portion of the inductor and a second capacitor. The second resonant circuit is configured to attenuate the first frequency components of the input signal to generate the filtered signal. A third resonant circuit includes a second portion of the inductor and a third capacitor, wherein the third resonant circuit is configured to attenuate second frequency components of the filtered signal above the cutoff frequency to generate an output signal.

A high-order filter with a capacitive inner tapping technique is disclosed. The filter includes an inductor and a first resonant circuit including a first portion of the inductor and a first capacitor. The first resonant circuit is configured to attenuate first frequency components of an input signal above a cutoff frequency to generate a filtered signal. The filter further includes a second resonant circuit coupled in parallel with the first resonant circuit and including the first portion of the inductor and a second capacitor. The second resonant circuit is configured to attenuate the first frequency components of the input signal to generate the filtered signal. A third resonant circuit includes a second portion of the inductor and a third capacitor, wherein the third resonant circuit is configured to attenuate second frequency components of the filtered signal above the cutoff frequency to generate an output signal.

Aspects of this disclosure relate to a radio frequency system with tunable notch filtering. The radio frequency system includes a first tunable filter and a second tunable filter. The first tunable filter is coupled between an output of a power amplifier and a radio frequency switch. The second tunable filter includes mutually coupled inductors and a tunable impedance circuit electrically connected to at least one of the mutually coupled inductors. The second tunable filter is coupled between an antenna switch and an antenna node. Related methods and wireless communication devices are also disclosed.