A radio-frequency module includes a first terminal configured to receive a signal from an antenna, a substrate, a first filter element on the substrate, a first switch including a first switch terminal and a second switch terminal connectable to the first switch terminal, and connected between the first terminal and the first filter element, and a second switch including a third switch terminal. The first filter element is connected between the second switch terminal and the third switch terminal, the first switch and the second switch are included in a semiconductor chip, and the semiconductor chip is on the substrate.

There is provided a dual-output microelectromechanical system (MEMS) resonator. The MEMS resonator can be operated selectively and concurrently in an in-plane mode of vibration and an out-of-plane mode of vibration to obtain respectively a first electrical signal having a first frequency, and a second electrical signal having a second frequency being less than the first frequency. The first and second electrical signals are mixed to obtain a third electrical signal having a third frequency, where the third frequency is proportional to a temperature of the MEMS resonator. The temperature is determined based on the third frequency. Values of the first and second frequencies can be adjusted based on the determined temperature to compensate for frequency deviations due to temperature deviations. There is also provided methods and systems for determining the temperature of the dual-output MEMS, for compensating the frequency, and a method of manufacturing the dual-output MEMS.

A switch module includes a first terminal, first and second filters, and first and second switches. Impedance of the first filter for a signal in a stop band is capacitive. When the first switch is turned OFF, impedance of the first switch is capacitive, and impedance of the first filter seen from an end portion of the first switch connected to the first filter is not in a short state and impedance of the first filter seen from the first terminal is in an open state.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

A radio-frequency module includes a first terminal configured to receive a signal from an antenna, a substrate, a first filter element on the substrate, a first switch including a first switch terminal and a second switch terminal connectable to the first switch terminal, and connected between the first terminal and the first filter element, and a second switch including a third switch terminal. The first filter element is connected between the second switch terminal and the third switch terminal, the first switch and the second switch are included in a semiconductor chip, and the semiconductor chip is on the substrate.

A method for reducing a quantity of cable runs to antennas can include the step of providing a circuit of reactive elements coupled between an input terminal and at least two output terminals. The circuit can be used to separate a broadband signal into two or more disjoint expected frequency ranges. The circuit can match the impedance at the at least two output terminals to the impedance expected by the antennas. The elements of the circuit can have reactances and arrangement so that when a broadband RF signal is applied at the input terminal, two or more disjoint expected frequencies can be applied to the respective output terminals. The power at each output terminal can sufficiently match the antennas' expected power, and insertion losses can be minimized.

A high-frequency switch includes an input interface configured to receive a high-frequency signal; an output interface configured to output the high-frequency signal to outside; and a reactance switch inserted between the input interface and the output interface. The reactance switch includes a plurality of reactance circuits connected in a cascade arrangement between the input interface and the output interface. Each of the plurality of reactance circuits is configured to form a common passband for the high-frequency signal based on a reactance of a respective predetermined values, and at least one of the reactance circuits is a variable reactance circuit having a reactance which changes in response to a control signal input from the outside so that the passband of the variable reactance circuit changes.

A switch module includes a first terminal, first and second filters, and first and second switches. Impedance of the first filter for a signal in a stop band is capacitive. When the first switch is turned OFF, impedance of the first switch is capacitive, and impedance of the first filter seen from an end portion of the first switch connected to the first filter is not in a short state and impedance of the first filter seen from the first terminal is in an open state.

A method for reducing a quantity of cable runs to antennas can include the step of providing a circuit of reactive elements coupled between an input terminal and at least two output terminals. The circuit can be used to separate a broadband signal into two or more disjoint expected frequency ranges. The circuit can match the impedance at the at least two output terminals to the impedance expected by the antennas. The elements of the circuit can have reactances and arrangement so that when a broadband RF signal is applied at the input terminal, two or more disjoint expected frequencies can be applied to the respective output terminals. The power at each output terminal can sufficiently match the antennas' expected power, and insertion losses can be minimized.

Embodiments may relate to a radio frequency (RF) front-end module (FEM) with a first filter and a second filter. The RF FEM may include a termination inductor coupled to ground, and a switch that is to selectively couple the first filter and the second filter to the termination inductor. Other embodiments may be described or claimed.