Examples provide a wideband filter structure and apparatus, a radio transceiver, a mobile terminal, and a method for filtering a radio signal. The wideband filter structure (10) for a radio signal comprises a combination of at least one acoustic resonator (12) and at least one analog resonator (14). The acoustic resonator (12) is coupled to the analog resonator (14). The wideband filter structure (10) comprises a further component (16), which is coupled to the combination of the acoustic resonator (12) and the analog resonator (14).

A resonant circuit includes a first inductor and a first capacitor which define a first series circuit and a second inductor connected in parallel to the first series circuit. The first inductor and the second inductor are coupled via a magnetic field in a direction in which magnetic fluxes passing through the inductor and the second inductor strengthen each other to effectively increase steepness in a transient band.

Certain aspects of the present disclosure provide a filter circuit and techniques for filtering using the filter circuit. The filter circuit generally includes a first filter stage having a first acoustic wave resonator coupled in a series path between a first port of the filter circuit and a second port of the filter circuit, a first inductor-capacitor (LC) tank circuit, a first capacitor coupled between a first terminal of the first acoustic wave resonator and the first LC tank circuit, the first LC tank circuit being coupled between the first capacitor and a reference potential node, and a second capacitor coupled between a second terminal of the first acoustic wave resonator and the first LC tank circuit. In some aspects, the filter circuit includes one or more other filter stages coupled to the first filter stage.

A planar structure for a planar radio frequency filter is configured to block the transmission of electromagnetic waves in at least two independent radio frequency bands, the planar structure comprising a periodic array of multipole inclusions, wherein the periodic array of multipole inclusions comprises a plurality of primary multipole inclusions having a plurality of primary poles to generate a lower frequency resonance and a plurality of secondary poles to generate a higher frequency resonance, wherein the periodic array of multipoles are arranged with arms of the plurality of primary poles overlapping with and substantially parallel to adjacent arms of the plurality of primary poles of adjacent multipole inclusions. The array of multipole inclusions may include a plurality of secondary multipole inclusions located between the plurality of primary multipole inclusions to tune the higher frequency resonance.

A multilayer filter includes an element body formed by stacking a plurality of insulator layers, and an input terminal, a first output terminal, and a ground terminal arranged on outer surfaces of the element body, a first LC resonance circuit provided in a line connecting the input terminal to the first output terminal and including a first inductor and a first capacitor, and an open inductor having one end connected to the ground terminal and the other end open are provided in the element body, and the open inductor is arranged to face the first output terminal or the first inductor.

A Wilkinson power divider includes: -type LPFs connected to an input terminal; a T-type HPF having one end connected to one of the -type LPFs and having another end connected to a carrier amplifier; another T-type HPF having one end connected to another one of the -type LPFs and having another end connected to a /4 line; and an isolation resistor connected to connection points.

A ladder-type filter includes: one or more series resonators connected in series between an input terminal and an output terminal; two or more parallel resonators connected in parallel between the input terminal and the output terminal; a first inductor connected in series between at least two nodes, each of the at least two nodes being located between a corresponding parallel resonator of at least two parallel resonators of the two or more parallel resonators and ground; and a first capacitor connected in series with the first inductor between the at least two nodes.

A Wilkinson power divider includes: -type LPFs connected to an input terminal; a T-type HPF having one end connected to one of the -type LPFs and having another end connected to a carrier amplifier; another T-type HPF having one end connected to another one of the -type LPFs and having another end connected to a /4 line; and an isolation resistor connected to connection points.

First to fourth filters of an electronic component are provided in a manner that a first path from the first filter to the second filter includes a second path from the third filter to the fourth filter and is also longer than the second path in a circuit configuration. First to fourth inductors of the first to fourth filters are arranged in a manner that an opening of the first inductor and an opening of the third inductor face each other, an opening of the second inductor and an opening of the fourth inductor face each other, and a pair of the second inductor and the fourth inductor is adjacent to a pair of the first inductor and the third inductor.

A multilayer circuit board with an LC resonant circuit that has an electronic component package including the multilayer circuit board with the LC resonant circuit are provided. The multilayer circuit board with the LC resonant circuit configured by alternately laminating conductive layers and insulating resin layers on both sides of a core substrate includes a first set of wiring lines, a set of vias, and a second set of wiring lines. The first set of wiring lines configures both ends of the LC resonant circuit and is formed in a first one of the conductive layers. The set of vias extends through the insulating resin layers. The second set of wiring lines is connected to an input/output terminal of the LC resonant circuit and is formed in a second one of the conductive layers. The first set of wiring lines is connected to the second set of wiring lines.