A front end module includes: a first antenna terminal; a second antenna terminal; a switch including a plurality of first side terminals on a first side and a plurality of second side terminals on a side opposite to the first side, each of the first side terminals being connected to one of the first antenna terminal and the second antenna terminal; a first filter connected to the first antenna terminal; a second filter connected to the first antenna terminal; a third filter connected to one of the second side terminals; and a fourth filter connected to one of the second side terminals. The third filter and the fourth filter are connected to one of the first antenna terminal and the second antenna terminal.

A filter is provided that includes a set of cascaded resonator stages coupled between a filter input and a first filter output, wherein the filter includes a second filter output coupled to an output of a first or an intermediate one of the set of cascaded resonator stages. Another filter includes a set of cascaded resonator stages coupled between a first filter input and a filter output, wherein the filter includes a second filter input coupled to an input of an intermediate or a last one of the set of cascaded resonator stages. Both filters are configured to apply a first filter frequency response to a first signal propagating via the set of cascaded resonator stages, and apply a second filter frequency response to a second signal propagating via a subset of one or more of the set of cascaded resonator stages.

A signal switch includes a first transistor coupled between first and second nodes, a plurality of second transistors coupled in series between the first and second nodes and in parallel with the first transistor, and a first shunt path including a first shunt transistor and a first inductor connected in series between a reference node and a first connection point between two of the plurality of second transistors.

A wireless transceiver includes: a switching amplifier having first, second and power ports; and a current provider. The current provider provides a current to the power port, and further provides an impedance to the power port such that an impedance of the switching amplifier at the second port matches an impedance of an antenna coupled to the second port. The switching amplifier simultaneously amplifies a transmit signal input received at the first port to generate an output signal at the second port for receipt by the antenna, and mixes a receive signal received at the second port from the antenna with the transmit signal input to generate, at the power port, another output signal having a frequency lower than that of the receive signal.

An example of a signal switch includes a first transistor coupled between first and second nodes, a plurality of second transistors coupled in series between the first and second nodes, in parallel with the first transistor, a third transistor coupled between the first node and a third node, and a plurality of fourth transistors coupled in series between the first and third nodes, in parallel with the third transistor. The signal switch further includes a first shunt path including a first shunt transistor and a first inductor connected in series between a reference node and a first connection point between two of the plurality of second transistors, and a second shunt path including a second shunt transistor and a second inductor connected in series between the reference node and a second connection point between two of the plurality of fourth transistors.

A signal switch includes a first node and a second node. A first transistor is coupled between the first and second nodes, and a plurality of second transistors is coupled in series between the first and second nodes, in parallel with the first transistor. A shunt transistor and inductor, coupled in series, are firstly connected between two of the plurality of second transistors and are secondly connected to a reference node.

Certain aspects of the present disclosure relate to multi-band filter architectures and methods for filtering signals using the multi-band filter architectures. One example multi-band filter generally includes a transconductance-capacitance (gm-C) filter and a reconfigurable load impedance coupled to an output of the gm-C filter, the reconfigurable load impedance comprising a first gyrator circuit coupled to a second gyrator circuit.

A wireless transceiver includes: a switching amplifier having first, second and power ports; and a current provider. The current provider provides a current to the power port, and further provides an impedance to the power port such that an impedance of the switching amplifier at the second port matches an impedance of an antenna coupled to the second port. The switching amplifier simultaneously amplifies a transmit signal input received at the first port to generate an output signal at the second port for receipt by the antenna, and mixes a receive signal received at the second port from the antenna with the transmit signal input to generate, at the power port, another output signal having a frequency lower than that of the receive signal.

Certain aspects of the present disclosure relate to multi-band filter architectures and methods for filtering signals using the multi-band filter architectures. One example multi-band filter generally includes a transconductance-capacitance (gm-C) filter and a reconfigurable load impedance coupled to an output of the gm-C filter, the reconfigurable load impedance comprising a first gyrator circuit coupled to a second gyrator circuit.

A filter is provided that includes a set of cascaded resonator stages coupled between a filter input and a first filter output, wherein the filter includes a second filter output coupled to an output of a first or an intermediate one of the set of cascaded resonator stages. Another filter includes a set of cascaded resonator stages coupled between a first filter input and a filter output, wherein the filter includes a second filter input coupled to an input of an intermediate or a last one of the set of cascaded resonator stages. Both filters are configured to apply a first filter frequency response to a first signal propagating via the set of cascaded resonator stages, and apply a second filter frequency response to a second signal propagating via a subset of one or more of the set of cascaded resonator stages.