A phase shifter includes a signal input, a signal output, an ESD protection circuit, first and second signal paths between the signal input and the signal output. The ESD protection circuit includes first and second two port devices, each two port device being switchable between a high impedance state and a low impedance state. The first signal path includes the first two port device of the ESD protection circuit and a first delay line configured to provide a first phase shift to a signal transmitted from the signal input to the signal output via the first signal path. The second signal path includes the second two port device of the ESD protection circuit and a second delay line configured to provide a second phase shift, different from the first phase shift, to the signal transmitted from the signal input to the signal output via the second signal path.

A phase shifter includes a signal input, a signal output, an ESD protection circuit, first and second signal paths between the signal input and the signal output. The ESD protection circuit includes first and second two port devices, each two port device being switchable between a high impedance state and a low impedance state. The first signal path includes the first two port device of the ESD protection circuit and a first delay line configured to provide a first phase shift to a signal transmitted from the signal input to the signal output via the first signal path. The second signal path includes the second two port device of the ESD protection circuit and a second delay line configured to provide a second phase shift, different from the first phase shift, to the signal transmitted from the signal input to the signal output via the second signal path.

An elastic wave device includes an LiNbO.sub.3 substrate, a first elastic wave resonator including a first IDT electrode and a first dielectric film, and a second elastic wave resonator including a second IDT electrode and a second dielectric film. A Rayleigh wave travels along at least one surface of the elastic wave device. A thickness of the first dielectric film differs from a thickness of the second dielectric film. A propagation direction of an elastic wave in the first elastic wave resonator coincides with a propagation direction of an elastic wave in the second elastic wave resonator. Euler angles of the LiNbO.sub.3 substrate fall within a range of (0°±5°, θ, 0°±10°).

An elastic wave device includes an LiNbO.sub.3 substrate, a first elastic wave resonator including a first IDT electrode and a first dielectric film, and a second elastic wave resonator including a second IDT electrode and a second dielectric film. A Rayleigh wave travels along at least one surface of the elastic wave device. A thickness of the first dielectric film differs from a thickness of the second dielectric film. A propagation direction of an elastic wave in the first elastic wave resonator coincides with a propagation direction of an elastic wave in the second elastic wave resonator. Euler angles of the LiNbO.sub.3 substrate fall within a range of (0°±5°, θ, 0°±10°).

Disclosed is a semiconductor device including a semiconductor die, a base member, a side wall, first and second conductive films, and first and second conductive leads. The base member has a conductive main surface including a region that mounts the semiconductor die. The side wall surrounds the region and is made of a dielectric. The side wall includes first and second portions. The first and second conductive films are provided on the first and second portions, respectively and are electrically connected to the semiconductor die. The first and second conductive leads are conductively bonded to the first and second conductive films, respectively. At least one of the first and second portions includes a recess on its back surface facing the base member, and the recess defines a gap between the at least one of the first and second portions below the corresponding conductive film and the base member.

A front end radio frequency (RF) module including one or more first filter circuits configured to implement a front end function by filtering first signals communicated between one or more first antenna and a transceiver and one or more second filter circuits configured to implement at least a portion of an additional network function within the front end RF module by filtering second signals communicated between one or more second antennas and the transceiver.

A front end radio frequency (RF) module including one or more first filter circuits configured to implement a front end function by filtering first signals communicated between one or more first antenna and a transceiver and one or more second filter circuits configured to implement at least a portion of an additional network function within the front end RF module by filtering second signals communicated between one or more second antennas and the transceiver.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

A frequency division duplex (FDD) first band includes a first downlink operating band and a first uplink operating band. An FDD second band includes a second downlink operating band and a second uplink operating band. In the FDD first band and the FDD second band, (1) the first downlink operating band, second downlink operating band, first uplink operating band, and second uplink operating band are positioned in order from lowest to highest frequency. The frequency range of the first uplink operating band and that of the second uplink operating band do not overlap each other. A filter is formed in or on a first substrate having piezoelectric properties and has a pass band including the first and second uplink operating bands.