An adjustment circuit is connected between a power generation circuit that converts environmental energy into electric power and a power conversion circuit that converts the electric power generated by the power generation circuit into a desired form. The adjustment circuit includes a first circuit unit and a second circuit unit. The first circuit unit is configured to have an input connected to the power generation circuit and an output connected to the power conversion circuit. The second circuit unit is configured to have a connection point connected to the first circuit unit, a grounding point connected to a grounding electric potential, and a capacitor connected between the connection point and the grounding point. A magnitude of output resistance included in the second circuit unit is smaller than a magnitude of output resistance included in the power generation circuit. The capacitor is charged with the electric power output from the power generation circuit and outputs the charged electric power to the power conversion circuit.

Radio frequency (RF) systems with tunable filters are provided herein. In certain embodiments, an RF system includes a first RF processing circuit configured to process a first frequency band of a first communication standard and a second frequency band of a second communication standard. The first frequency band and the second frequency band are close in frequency and/or partially overlapping in frequency. The first RF processing circuit includes a tunable filter for changing the bandwidth of the first RF processing circuit to enhance the robustness of the first RF processing circuit to blocker or jammer signals of a third frequency band.

An apparatus includes a transceiver circuit, a series capacitor, and a shunt switch. The transceiver circuit may comprise a transmit chain including an output matching network and a receive chain including an input matching network. An output of the output matching network may be connected directly to an input/output of the transceiver circuit. The series capacitor may be connected between an input of the input matching network and the output of the output matching network. The shunt switch may be connected between the input of the input matching network and a circuit ground potential of the transceiver circuit.

A trap filter includes a first inductor, a second inductor, and a capacitor. A first end of the first inductor extends to a first connection portion, a third end of the second inductor is connected to a second end of the first inductor, and a fourth end extends to a second connection portion. The capacitor is connected in parallel with the second inductor. The first inductor and the second inductor are subtractive-polarity coupled. An inductance value of the second inductor is less than an absolute value of mutual inductance generated by coupling of the first inductor and the second inductor.

A multilayer substrate includes a pair of first capacitor electrodes, a pair of second capacitor electrodes, and a dielectric substrate. Electrodes of the pair of first capacitor electrodes are disposed in dielectric substrate so as to face each other in a thickness direction of the dielectric substrate. Electrodes of the pair of second capacitor electrodes are disposed in the dielectric substrate so as to face each other in the thickness direction. A first element and a second element that are disposed in or on the dielectric substrate, and the pair of second capacitor electrodes, the pair of first capacitor electrodes, and a ground electrode that are disposed in the dielectric substrate are arranged in the stated order in the thickness direction. The pair of second capacitor electrodes at least partially overlaps the pair of first capacitor electrodes when viewed in plan in the thickness direction.

A band pass filter includes: a first circuit unit including a first series LC resonant circuit disposed between a first terminal and a second terminal; a second circuit unit disposed between the first circuit unit and the second terminal, and including a first parallel LC resonant circuit; and a third circuit unit disposed between the first terminal and a ground, and including a second series LC resonant circuit, wherein a resonant frequency of the first circuit unit is in a pass band.

A low pass filter includes a first inductor, a second inductor magnetic-field-coupled to the first inductor, a third inductor, and a first capacitor. The first inductor is electrically connected between a first port and an intermediate node, being a node to which the second inductor is electrically connected, between the first inductor and the second port. The second inductor is electrically connected between the intermediate node and a ground terminal. The third inductor is electrically connected between the intermediate node and the second port, and a first parallel resonant circuit is defined by the third inductor and the first capacitor. The first inductor and the second inductor are coupled to each other in such a relationship that a negative inductance is generated between the intermediate node and the third inductor due to magnetic field coupling between the first inductor and the second inductor.

Aspects of the present disclosure provide three-dimensional (3D) through-glass-via (TGV) inductors for use in electronic devices. In some embodiments, a first portion of a 3D TGV inductor may be formed in a first wafer and a second portion of a 3D TGV may be formed in a second wafer. The first portion and second portion may be bonded together in a bonded wafer device thereby forming a larger inductor occupying relatively little wafer space on the first and the second wafers.

A band pass filter includes: a first circuit unit including a first series LC resonant circuit disposed between a first terminal and a second terminal; a second circuit unit disposed between the first circuit unit and the second terminal, and including a first parallel LC resonant circuit; and a third circuit unit disposed between the first terminal and a ground, and including a second series LC resonant circuit, wherein a resonant frequency of the first circuit unit is in a pass band.

A radio frequency (RF) filter circuit for rejecting one or more spurious components of an input signal has a first resonator circuit including a first capacitor and a first coupled inductor pair of a first inductor and a second inductor, and a second resonator circuit with a second capacitor and a second coupled inductor pair of a third inductor and a fourth inductor. First and second resonator coupling capacitors are connected to the first resonator circuit and the second resonator circuit. A first port and a second port are connected to the first resonator circuit and the second resonator, with the filtered signal of the input signal passed through both the first resonator circuit and the second resonator circuit being output.