A high performance integrated tunable impedance matching network with coupled merged inductors. Embodiments include a combination of merged multiport constructively coupled spiral inductors and tunable capacitors configured to reduce insertion losses, circuit size, and optimization time while maintaining a high Q factor for the coupled spiral inductors. Some embodiments integrate one or more filter circuits with a tunable impedance matching network, useful in conjunction with such applications as radio frequency power amplifiers.

Multiple LC parallel resonators in which inductors and capacitors are connected in parallel are located inside a multilayer body. The inductors each include a loop inductor including a line-shaped conductor pattern and at least one pair of via conductors connected to the line-shaped conductor pattern. When the multilayer body is seen through in a height direction, in all the loop inductors of the LC parallel resonators, open via conductors are closer to a center of the multilayer body, and short-circuit via conductors are closer to an outer side of the multilayer body in at least one of a width direction and a length direction.

A front end circuit is disclosed. In an embodiment, the circuit includes a first antenna connection and first to third signal paths, each of which include a tunable filter and each of which is connected to the first antenna connection. The circuit further includes at least one phase shifter arranged in at least one of the signal paths between a respective filter and the first antenna connection and a control circuit configured to tune frequency bands of the filters, wherein the filters are operable in a FDD operating mode or a TDD operating mode, and wherein the front-end circuit is simultaneous operable in at least one transmission band and at least one reception band using all three filters and the associated signal paths.

Methods and apparatus, including computer program products, are provided filters. In some example embodiments, there is provided a radio frequency filter including at least one resonant circuit selectable to vary at least the selectivity of the radio frequency filter, wherein the selectivity is varied based on at least one of a first amount of transmit power being used at a user equipment and a second amount of received signal power. Related apparatus, systems, methods, and articles are also described.

A differential and common mode filter for an inverter, comprising an inductor having a core. The core comprises: an upper joke and a lower joke which comprise a first magnetic material; a first leg, a second leg and a third leg which extend between the upper and lower jokes and around which a first coil, a second coil, and a third coil are arranged, respectively, wherein at least one portion of the first, second and third legs, when seen in a transverse cross section, is made of one second magnetic material, and wherein the first magnetic material has a magnetic permeability higher than the second magnetic material; at least one unwound leg extending between the upper and lower jokes.

A phase characteristic measurement device includes a first detector 11 that receives and detects two patterns of three-tone signals of a first three-tone signal obtained by combining the three waves of angular frequencies .sub.1, .sub.2, .sub.3 (wherein .sub.2.sub.1=.sub.3.sub.2=) and a second three-tone signal obtained by changing a phase of one tone out of the first three-tone signal, a BPF 12 that allows only a beat component of an angular frequency difference of adjacent waves of the three-tone signal from the signal output from the first detector to pass therethrough, a second detector 13 that detects power of the beat component that has passed through the BPF 12, a voltmeter 14 that measures the voltage of the signal output from the second detector, and a phase calculator 15 that calculates the phase based on the measured voltage value.

In a multilayer filter, first and second resonant circuits are arranged in a direction crossing a stacking direction of a plurality of dielectric layers. An input/output portion includes an input/output port group including an unbalanced port and a pair of balanced ports or an input/output port group including two pairs of balanced ports. The second resonant circuit includes an inductor conductor, a first capacitor conductor, and a second capacitor conductor. The inductor conductor includes first and second ends. The first capacitor conductor is connected to the first end. The second capacitor conductor is connected to the second end. The second dielectric layer has a dielectric constant lower than that of the first dielectric layer. The first and second capacitor conductors are provided in the first dielectric layer. At least a part of the inductor conductor is provided in the second dielectric layer.

A filter includes a first port, a second port, and a high-pass filter provided between the first port and the second port in a circuit configuration. The high-pass filter includes a first capacitive element provided in a path connecting the first port and the second port, an inductor provided between the path and the ground, and a second capacitive element connected in parallel with the inductor.

Embodiments herein relate to an apparatus and method for calibrating a notch filter which filters a power supply signal for a voltage-controlled oscillator (VCO). In one aspect, a control circuit performs a number of calibration cycles for the filter to determine a value of a calibration code for the filter which minimizes a change in a frequency of the output signal of the VCO due to a change in the voltage of the power supply signal. After each calibration cycle, the calibration code is adjusted based on whether the frequency of the output signal increase or decreases. The calibration cycles can therefore converge on an optimal calibration code which minimizes the change in frequency due to the change in voltage. This minimizes a sensitivity of the VCO to noise in the power supply signal.

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.