A high frequency multilayer filter may include a plurality of dielectric layers and a signal path having an input and an output. The multilayer filter may include an inductor including a conductive layer formed over a first dielectric layer. The inductor may be electrically connected at a first location with the signal path and electrically connected at a second location with at least one of the signal path or a ground. The multilayer filter may include a capacitor including a first electrode and a second electrode that is separated from the first electrode by a second dielectric layer. The multilayer filter has a characteristic frequency that is greater than about 6 GHz.

A multilayer filter may include a dielectric layer having a top surface, a bottom surface, and a thickness in a Z-direction between the top surface and the bottom surface. The multilayer filter may include a conductive layer formed on the top surface of the dielectric layer. The multilayer filter may include a via assembly formed in the dielectric layer and connected to the conductive layer on the top surface of the dielectric layer. The via assembly may extend to the bottom surface of the dielectric layer. The via assembly may have a length in the Z-direction and a total cross-sectional area in an X-Y plane that is perpendicular to the Z-direction. The via assembly may have an area-to-squared-length ratio that is greater than about 3.25.

A multilayer band pass filter includes a first LC parallel resonator electrically connected to a first input/output terminal, a second LC parallel resonator electrically connected to a second input/output terminal, and a third LC parallel resonator is magnetically coupled to the first LC parallel resonator. The first LC parallel resonator includes a first inductor. The second LC parallel resonator includes a second inductor. The third LC parallel resonator is magnetically coupled to the second LC parallel resonator. A bypass connects the first inductor and the second inductor to each other.

A front end module includes a base filter configured to operate as a bandpass filter passing a pass band of an input radio frequency signal; a switch connected to the base filter, and a first notch filter and a second notch filter selectively connected to the base filter through the switch, wherein a stop band of the first notch filter and a stop band of the second notch filter overlap the pass band of the base filter in a band equal to or higher than a center frequency of the pass band of the base filter.

Filter circuits having acoustic wave resonators in a transversal configuration are disclosed. In the transversal configuration, the acoustic wave resonators are arranged transverse to an input and output port of the filter circuit. As such, all the acoustic wave resonators of the filter circuit are connected to the input port and connected to the output port. In the transversal configuration, the filter circuit can be designed for any transfer function without being restricted to a coupling coefficient of a piezoelectric material used in the acoustic wave resonators. In this regard, the filter circuit can achieve very wideband filter responses, multiband responses, and/or responses with arbitrary position of transmission zeros. The filter circuit having the transversal configuration can also be designed for complex transmission zeros for phase equalization.

A filter element is mounted on a module substrate. The filter element includes a ground terminal and a pair of signal terminals. The module substrate includes a ground plane, a ground land, and an inductance adjusting line that connects the ground land to the ground plane. The ground terminal of the filter element is connected to the ground land of the module substrate. The inductance adjusting line includes an in-plane extending portion that extends in an in-plane direction of the module substrate.

A filter device is mounted on a module substrate and is shielded by a shield member. The filter device has first and second side surfaces opposed to each other. A ground terminal and signal terminals are formed on a bottom surface of the filter device. The shield member includes side wall portions facing the first and second side surfaces. The filter device includes plural LC parallel resonance circuits therein. The inductors of the LC parallel resonance circuits are arranged in parallel with the first side surface and the bottom surface. Each inductor extends upward from its end portion electrically connected to the ground terminal, extends from the first side surface toward the second side surface, and then extends toward the bottom surface. The gap between the first side surface and the corresponding side wall portion is smaller than that between the second side surface and the corresponding side wall portion.

A diplexer having a low band filter and a high band filter is disclosed. The disclosure provides a diplexer having a low band filter and a high band filter for preventing the circuit damage due to an electrostatic discharge in the diplexer itself, and minimizing the signal loss according to addition of an electrostatic discharge prevention circuit.

A high pass filter includes: a first resonant circuit including an inductor and a capacitor in parallel between first and second terminals; a second resonant circuit including an inductor and a capacitor in series between a first end of the first resonant circuit and a ground; a third resonant circuit including an inductor and a capacitor in series between a second end of the first resonant circuit and the ground; a fourth resonant circuit disposed between the first end of the first resonant circuit and the first terminal, and including a first acoustic resonator; and a fifth resonant circuit disposed between the second end of the first resonant circuit and the second terminal, and including a second acoustic resonator. Attenuation regions respectively formed by the first, second, and third resonant circuits are arranged in lower frequency regions than attenuation regions respectively formed by the fourth and fifth resonant circuits.

A positive electrode side input loop line (10a) and a positive electrode side output loop line (10b), and a negative electrode side input loop line (11a) and a negative electrode side output loop line (11b) form two sets of coupling loops, and the loop lines of the two sets have the same winding direction, and have the same loop sizes of and relative relationship between the loop lines. A capacitor (3) is connected in series between the positive electrode side input loop line (10a) and the negative electrode side input loop line (11a).