The present disclosure provides circuits and methods for fabricating circuits. A circuit may include an insulator having a first surface, a second surface, a periphery, a first subset of circuit elements disposed on the first surface, a second subset of circuit elements disposed on the second surface, and at least one conductive sidewall disposed on the periphery, wherein the conductive sidewall electrically couples the first subset of circuit elements to the second subset of circuit elements.

A wireless communication device and a filter are provided. The filter has an input end and an output end and includes a first energy storage element, a first series resonant circuit, a second series resonant circuit, a first parallel resonant circuit and a second parallel resonant circuit. The first and the second series resonant circuits respectively have a first capacitor and a first inductor connected in series. The first and the second parallel resonant circuits respectively have a second capacitor and a second inductor connected in parallel. The first series resonant circuit and the first parallel resonant circuit are electrically connected in cascade between a first end of the first energy storage element and a ground, and the second series resonant circuit and the second parallel resonant circuit are electrically connected in cascade between a second end of the first energy storage element and the ground.

The present disclosure provides a variable filter circuit capable of controlling a band width and a center frequency of a pass band, and also capable of suppressing the total number of pieces of variable reactance. That is, a variable filter circuit includes a serial arm in which a plurality of circuit elements are connected in series with respect to a signal path and a parallel arm in which a plurality of circuit elements are connected in parallel with respect to the signal path, wherein the serial arm and the parallel arm each includes a variable reactance element, a series reactance element that is connected in series to the variable reactance element and resonates therewith, and a parallel reactance element that is connected in parallel to the variable reactance element and resonates therewith.

A filter includes shunt circuits coupled between a reference node and each of an input port, an output port, a first node, and a second node. Resonant networks are coupled between the input port and the second node, and between the first node and the output port. Storage element circuits are coupled between the input port and the first node, and between the second node and the output port. The shunt circuits have an equivalent shunt circuit frequency response that partly defines a high passband frequency of the filter, the resonant networks have an equivalent resonant network frequency response that partly defines a low passband frequency of the filter, and the storage element circuits have an equivalent storage element circuit frequency response that defines a stopband frequency of the filter between the low passband frequency and the high passband frequency.

A filter device includes a multilayer body in which multiple dielectric layers are stacked, a ground terminal, and a first LC parallel resonator, a second LC parallel resonator, and a third LC parallel resonator located in the multilayer body and magnetically coupled to each other. The first LC parallel resonator includes a first conductor, the second LC parallel resonator includes a second conductor, and the third LC parallel resonator includes a third conductor. The filter device further includes a connection conductor on a layer different from a layer on which the second conductor is located, a first via including one end connected to the first conductor and another end connected to the connection conductor, and a second via including one end connected to the third conductor and another end connected to the connection conductor. The connection conductor includes a first region that overlaps a portion of the second conductor in plan view of the multilayer body seen in a stacking direction.

A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

A multi-bit digital signal that is generated by modulating a baseband signal by a modulation circuit and includes components in a radio frequency band is amplified by switch-mode amplifiers (100-1, 100-2) on a bit-by-bit basis, amplified signals are band-limited by frequency-variable variable band limiting units (201-1, 201-2) and thereafter subjected to voltage-to-current conversion by voltage/current source conversion units (202-1, 202-2) provided with variable capacitances, the signals converted to current are synthesized at a synthesis point X, and a resultant signal is impedance-corrected by an impedance correction unit (203) and output as a transmission signal to an antenna of a load (300). Consequently, the present invention provides a transmitter capable of synthesizing output signals from a plurality of switch-mode amplifiers and transmitting a resultant signal while maintaining an impedance characteristic with respect to a plurality of transmit frequencies without increasing a circuit size.

A multilayer fringe capacitor includes first and second interdigitated capacitor electrodes, both parallel to and intersecting a first planar surface; third and fourth interdigitated capacitor electrodes, the first and second electrodes parallel to and separated by a non-zero distance from the third and fourth electrodes; a first set of coupling vias that electrically couples the first electrode to the third electrode; and a second set of coupling vias that electrically couples the second electrode to the fourth electrode.

RF circuitry, which includes a first passive voltage-gain network and a first MOS-based RF receive amplifier, is disclosed. The first passive voltage-gain network provides a first passive RF receive signal using a first RF receive signal, such that an energy of the first passive RF receive signal is obtained entirely from the first RF receive signal by the first passive voltage-gain network. A voltage of the first passive RF receive signal is greater than a voltage of the first RF receive signal. The first MOS-based RF receive amplifier receives and amplifies the first passive RF receive signal to provide a first amplified RF receive signal.

A filter circuit is provided which allows the pass band to be tuned to a desired communication signal while achieving increased attenuation in a given frequency band that lies outside the pass band. A filter circuit includes a fixed filter and a tunable filter. The fixed filter has a pass band wider than a frequency band corresponding to a predetermined communication signal and overlapping with the frequency band corresponding to the communication signal. The tunable filter has a stop band narrower than the pass band of the fixed filter and having tunable frequency. The fixed filter and the tunable filter are connected in series.