A band antenna EMP filter apparatus having HEMP protection capability is disclosed. The apparatus includes a discharging part, a band pass filtering part, and a residual current eliminating part. The discharging part primarily discharges a transient voltage due to a high altitude electromagnetic pulse (HEMP) when the HEMP is inputted through an input part receiving a radio frequency (RF) signal of an antenna. The band pass filtering part secondarily blocks a residual current primarily discharged by the discharging part and passes only a signal of a preset frequency band to output it through an output part. The residual current eliminating part limits a transient voltage of the HEMP by eliminating a residual current passing through the band pass filtering part.

In one embodiment, a tuning network includes: a controllable capacitance; a first switch coupled between the controllable capacitance and a reference voltage node; a second switch coupled between the controllable capacitance and a third switch; the third switch coupled between the second switch and a second voltage node; a fourth switch coupled between the second voltage node and a first inductor; the first inductor having a first terminal coupled to the fourth switch and a second terminal coupled to at least the second switch; and a second inductor having a first terminal coupled to the second terminal of the first inductor and a second terminal coupled to the controllable capacitance.

A filter includes an input terminal, an output terminal, a plurality sets of first capacitors that include first ends connected to a plurality sets of first nodes, respectively, at different locations in a path capable of transmitting a high frequency signal from the input terminal to the output terminal, and second ends commonly connected to a second node, a plurality sets of first inductors that include third ends connected to the first nodes, respectively, and the fourth ends commonly connected to a third node, a second inductor that includes a fifth end connected to the second node, and a sixth end grounded, and a third inductor that includes a seventh end connected to the third node, and an eighth end grounded.

In a multilayer filter, a first LC parallel resonance unit, a second LC parallel resonance unit, and an LC circuit unit are configured in an element body, in which the LC circuit unit is connected between the first LC parallel resonance unit and the second LC parallel resonance unit in a path between a first terminal electrode and a second terminal electrode, a conductor pattern constituting an inductor of the LC circuit unit is not disposed between a conductor pattern constituting a first inductor of the first LC parallel resonance unit and a conductor pattern constituting a second inductor of the second LC parallel resonance unit in the element body, and the first inductor of the first LC parallel resonance unit and the second inductor of the second LC parallel resonance unit are magnetically coupled.

A filter assembly is disclosed that includes a monolithic filter having a surface and a heat sink coupled to the surface of the monolithic filter. The heat sink includes a layer of thermally conductive material that can have a thickness greater than about 0.02 mm. The heat sink may provide electrical shielding for the monolithic filter. In some embodiments, the filter assembly may include an organic dielectric material, such as liquid crystalline polymer or polyphenyl ether. In some embodiments, the filter assembly may include an additional monolithic filter.

An even-mode resonator filter is disclosed. The even-mode resonator filter is provided with high stability, and comprises: a first even-mode resonance module, a second even-mode resonance module, a first filter unit and a second filter unit. In the present invention, the first even-mode resonance module comprises a first resonance unit and a second resonance unit, and the second even-mode resonance module comprises a third resonance unit and a fourth resonance unit. By letting the second resonance unit be coupled to the first resonance unit as well as making the third resonance unit be coupled to the fourth resonance unit, the even-mode resonator filter of the present invention has the advantage of eliminating unexpected resonance.

Aspects of this disclosure relate to a band pass filter that includes LC resonant circuits coupled to each other by a capacitor. A bridge capacitor can be in parallel with series capacitors, in which the series capacitors include the capacitor coupled between the LC resonant circuits. The bridge capacitor can create a transmission zero at a frequency below the passband of the band pass filter. The LC resonant circuits can each include a surface mount capacitor and a conductive trace of the substrate, and an integrated passive device die can include the capacitor. Band pass filters disclosed herein can be relatively compact, provide relatively good out-of-band rejection, and relatively low loss.

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.

A multilayer filter may include a plurality of dielectric layers stacked in a Z-direction. A first conductive layer may overlie one of the dielectric layers, and a second conductive layer may overlie another of the dielectric layers and be spaced apart from the first conductive layer in the Z-direction. A first via may be connected with the second conductive layer at a first location. A second via may be connected with the second conductive layer at a second location that is spaced apart in a first direction from the first location. The first conductive layer may overlap the second conductive layer at an overlapping area to form a capacitor. At least a portion of the overlapping area may be located between the first location and the second location in the first direction. The second conductive layer may be free of via connections that intersect the overlapping area.

A filter device includes a first port, a second port, a first high-pass filter, a first low-pass filter, and a stack. The first high-pass filter includes a first inductor. The first low-pass filter includes a first inductor. At least one second conductor layer constituting the first inductor of the first low-pass filter is located between at least one first conductor layer constituting the first inductor of the first high-pass filter and a ground conductor layer in a stacking direction.