Embodiments of radio frequency (RF) filtering circuitry are disclosed. In one embodiment, the RF filtering circuitry includes a common port, a second port, a third port, a first RF filter path, and a second RF filter path. The first RF filter path is connected between the common port and the second port and comprises a first pair of resonators and a first acoustic wave resonator. One of the first pair of resonators also includes a second acoustic wave resonator. The second RF filter path is connected between the common port and the third port. The second RF filter path includes a second pair of resonators. The first and second acoustic wave resonators of the first RF filter path increase roll-off greatly with respect to just an LC filter, and thereby allow for an increase out-of-band rejection at high frequency ranges.

A front end circuit is disclosed. In an embodiment, the circuit includes a first antenna connection and first to third signal paths, each of which include a tunable filter and each of which is connected to the first antenna connection. The circuit further includes at least one phase shifter arranged in at least one of the signal paths between a respective filter and the first antenna connection and a control circuit configured to tune frequency bands of the filters, wherein the filters are operable in a FDD operating mode or a TDD operating mode, and wherein the front-end circuit is simultaneous operable in at least one transmission band and at least one reception band using all three filters and the associated signal paths.

Systems and methods are provided for implementing bandstop filters (e.g., RF/microwave bandstop filters) that can automatically tune to a frequency of an interfering signal. Embodiments of the present disclosure provide automatically tunable signal-tracking bandstop filters with a significant reduction in response time, complexity, size, weight, and cost when compared to conventional devices.

A diplexer includes a multilayer substrate, first, second, and third terminals, and a ground terminal provided on the multilayer substrate. The first filter is between the first terminal and the second terminal, the second filter is between the first terminal and the third terminal. An interlayer spacing of the multilayer substrate includes a first filter ground electrode, a second filter ground electrode, and a shield ground electrode shielding between the first filter and the second filter. The ground terminal includes a first filter ground terminal connected to the first filter ground electrode, a second filter ground terminal connected to the second filter ground electrode, and a shield ground terminal connected to the shield ground electrode.

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.

Impedance matching circuit for radio-frequency amplifier. In some embodiments, an impedance matching circuit can include a primary metal trace having a first end configured to be capable of being coupled to a voltage source for the power amplifier, and a second end configured to be capable of being coupled to an output of the power amplifier. The impedance matching circuit can further include a secondary metal trace having first end coupled to the second end of the primary metal trace, and a second end configured to be capable of being coupled to an output node. The impedance matching circuit can further include a capacitance implemented between the first and second ends of the secondary metal trace, and be configured to trap a harmonic associated with an amplified signal at the output of the power amplifier.

A branching filter includes a first band-pass filter provided between a common port and a first signal port, and a second band-pass filter provided between the common port and a second signal port. The first band-pass filter includes a first LC resonant circuit and a first resonant circuit section provided in series. The first resonant circuit section includes a first acoustic wave resonator. The second band-pass filter includes a second LC resonant circuit and a second resonant circuit section provided in series. The second resonant circuit section includes a second acoustic wave resonator and an inductor connected in parallel.

A filter circuit in a radio frequency power detection circuit includes input and output lines, wherein: an input terminal of the input and output lines is connected with a first capacitor, the first capacitor is connected with a first filtering sub-circuit; the first filtering sub-circuit is connected with a third capacitor, the third capacitor is connected with a second filtering sub-circuit; the second filtering sub-circuit is connected with an output terminal of the input and output lines. The filter circuit of the present invention is able to effectively improve the detection accuracy of the radio frequency electric source output power, thereby improving the power output accuracy of the radio frequency electric source.

Systems and methods are provided for implementing bandstop filters (e.g., RF/microwave bandstop filters) that can automatically tune to a frequency of an interfering signal. Embodiments of the present disclosure provide automatically tunable signal-tracking bandstop filters with a significant reduction in response time, complexity, size, weight, and cost when compared to conventional devices.

An electronic component is mounted on a circuit board such that a mounting surface of an element body to which a first outer electrode and a second outer electrode are exposed is directed toward the circuit board. A coil is formed of a spiral coil in which a plurality of coil conductor layers arranged in a direction perpendicular to a first side surface and a second side surface orthogonal to the mounting surface are connected in series. Then, an intermediate point between a lowest point closest to the mounting surface and an uppermost point farthest from the mounting surface in an inner circumference of the coil is offset from the center of the element body in a direction perpendicular to the mounting surface toward the opposite side to the mounting surface.