A filter circuit includes a pair of balanced input ports, a pair of balanced output ports, and first and second resonators provided in parallel between the pair of balanced input ports and the pair of balanced output ports in a circuit configuration, the first and second resonators being magnetically coupled to each other. Between the first resonator and the second resonator, a capacitor is present but no inductor is present in the circuit configuration.

Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

A filter circuit includes a pair of balanced input ports, a pair of balanced output ports, first and second resonators provided in parallel between the pair of balanced input ports and the pair of balanced output ports in a circuit configuration, a first capacitor connected in parallel to the first resonator, and a second capacitor connected in parallel to the second resonator. The first and second resonators are magnetically coupled to each other and electrically connected to each other. The first and second capacitors are not electrically connected to ground.

The present disclosure provides a filter circuit and an electronic device, and relates to the field of filters. The filter circuit can include a filter and a suppression ring, the suppression ring can be arranged around a periphery of the filter, the filter can include several grounded ports, each of grounded ports can be electrically connected to the suppression ring, and each of grounded ports can be grounded. The out-of-band rejection capability of the filter can be greatly improved by providing the suppression ring on the periphery of the filter and connecting each of grounded ports to the suppression ring before grounding.

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.

A filter device includes a multilayer substrate, an inductor, and a first open stub. The multilayer substrate includes a first wiring layer, a second wiring layer including a first reference electrode to which a reference potential is supplied, and a plurality of first dielectric layers between the first wiring layer and the second wiring layer. The inductor has one end coupled to a first terminal and another end coupled to a second terminal. A portion of the first open stub is provided in the first wiring layer, and the first open stub has one end coupled to the one end of the inductor and another open-circuited end. When the multilayer substrate is viewed in plan view in a stacking direction, a capacitor is formed by the first reference electrode and the first open stub that mutually overlap. A resonant circuit is formed by the capacitor and the inductor.

In a multilayer filter, first to fourth resonant circuits are connected to an input/output portion. The 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. Each of the first to fourth resonant circuits includes an inductor conductor and first and second capacitor conductors. 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 and third resonant circuits are magnetically coupled to each other. The second and third resonant circuits are arranged between the first resonant circuit and the fourth resonant circuit in a first direction. Each of first and second electrodes of a jump capacitor conductor is connected to the inductor conductors of the first and fourth resonant circuits.

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.

Aspects of this disclosure relate to a radio frequency filter with two pass bands. The RF filter employs a first RF bandpass filter coupled to a common RF input and a common RF output. The RF filter further employs a second RF bandpass filter coupled to the common RF input and the common RF output. A first RF pass band of the first RF bandpass filter and a second RF pass band of the RF second bandpass filter are overlapping RF pass bands. Related methods and wireless communication devices are also disclosed.

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.