According to some embodiments, an on-chip diplexer circuit is disclosed. The on-chip diplexer circuit includes a LC resonator module, the LC resonator module further comprises a first port, a first LC resonator unit and a second LC resonator unit; a first filter unit, the first filter unit is electrically connected to the first LC resonator unit in the LC resonator module, and the first filter unit is electrically connected to a second port; and a second filter unit, the second filter unit is electrically connected to the second LC resonator unit in the LC resonator module, and the second filter unit is electrically connected to a third port. According to some embodiments, the first LC resonator unit serves as an impedance matching circuit for a first signal having a first resonant frequency and serves as an open circuit for a second signal having a second resonant frequency that is different from the first resonant frequency; the second LC resonator unit serves as an impedance matching circuit for the second signal having the second resonant frequency and serves as an open circuit for the first signal having the first resonant frequency. The first filter unit passes signals with the first resonant frequency; and the second filter unit passes signals with the second resonant frequency.

A power combiner/divider circuit can be structured having a base structure with the addition of an odd-mode capacitor and a low pass network at an end of the base structure or structured having a base structure with the addition of an inductor and a high pass network at an end of the base structure. The power combiner/divider circuit can be implemented as a port coupled to multiple ports with low pass networks or high pass networks arranged at the ends of paths to the multiple ports. In embodiments using low pass base structures or low pass networks coupled to the base structures, inductors in such low pass sections can be positively coupled on a pair-wise basis.

A filter device includes series and parallel arm resonators provided at a filter chip and inductors electrically connected in series with respective ones of the parallel arm resonators. A first inductor having the highest inductance of the inductors is electrically connected in series with a first parallel arm resonator having the highest anti-resonant frequency of the parallel arm resonators. One end of the first parallel arm resonator and one end of a second parallel arm resonator in other ones of the parallel arm resonators are electrically connected to a same wiring line in wiring lines separated by the series arm resonators on a line electrically connecting an input terminal and an output terminal of the filter chip. The other ends of the first and second parallel arm resonators are respectively electrically connected to first and second ground terminals of the filter chip.

Systems and methods are disclosed for on-chip harmonic filtering for radio frequency (RF) communications. For disclosed embodiments, a filter circuit is coupled between a first internal node and a connection pad for an integrated circuit. The filter circuit includes a first inductance, a variable capacitance, and a second inductance. The capacitance amount for the variable capacitance is controlled to tune filtering for the filter circuit to a harmonic of a frequency for a transmit output signal. A power amplifier outputs the transmit output signal to the connection pad without passing through the filter circuit. The filter circuit filters the harmonic of the frequency for the transmit output signal, shunting harmonic current to ground. For one embodiment, the filtered harmonic is a third harmonic of the transmit frequency. For one embodiment, the transmit output signal has an output power greater than or equal to 15 dBm.

An integrated passive die includes a substrate, an input node, an output node, and RF filtering circuitry. The RF filtering circuitry includes a number of LC tank circuits coupled between the input node and the output node. Each one of the LC tank circuits include an inductor and a capacitor. The inductor is formed by a metal trace over the substrate. The capacitor is coupled in parallel with the inductor over the substrate. The inductor and the capacitor are provided such that a resonance frequency of the combination of the inductor and the capacitor is less than a self-resonance frequency of the inductor.

Disclosed herein is an LC filter that includes a conductive substrate, a first capacitive insulating film having one surface covered with the conductive substrate and other surface covered with a first capacitive electrode, a first inductor pattern having one end connected to the first capacitive electrode, a first terminal electrode connected to other end of the first inductor pattern, and a common terminal electrode connected to the conductive substrate.

An inductor device includes a first trace, a second trace, and a capacitor. The first trace includes at least two sub-traces. One terminal of each of the at least two sub-traces are coupled to each other at a first node. The second trace includes at least two sub-traces. One terminal of each of the at least two sub-traces are coupled to each other at a second node. The capacitor is coupled to the firs node and the second node.

An inductor device includes first trace, second trace, third trace, fourth trace, first capacitor, and second capacitor. One terminal of each of the at least two sub-traces of first trace are coupled to each other at first node. One terminal of each of the at least two sub-traces of second trace are coupled to each other at second node. One terminal of third trace is coupled to second trace, and another terminal of third trace is coupled to first input/output terminal. One terminal of fourth trace is coupled to first trace, and another terminal of fourth trace is coupled to second input/output terminal. First capacitor is coupled to first node and second node. Second capacitor is coupled between firs node and first input/output terminal, or coupled between first node and second input/output terminal, or coupled between first input/output terminal and second input/output terminal.

A filter structure includes a capacitive device and an inductive device. The capacitive device includes a ground plane in a first metal layer of an integrated circuit (IC) package, a plate in a second metal layer of the IC package, and a dielectric layer between the ground plane and the plate. The inductive device includes first and second conductive paths in a third metal layer of the IC package, each of the first and second conductive paths is electrically connected to the plate and has a width w, the first and second conductive paths are separated by a spacing s, and a ratio s/w has a value ranging from 1 to 2.

Embodiments of the present invention provide an inductively coupled filter and a WiFi module. The inductively coupled filter includes a first circuit, where the first circuit is disposed on a first substrate; and a second circuit, where the second circuit is disposed on a second substrate; and the first substrate and the second substrate are disposed opposite to each other, so that a coil inductor in the first circuit and a coil inductor in the second circuit form a mutual induction structure. In the inductively coupled filter in the embodiments of the present invention, the coil inductors are disposed on two substrates respectively. This can reduce an area occupied by the inductively coupled filter on each package substrate.