Radio frequency switch circuit

A circuit comprising:

• a first amplifier configured to receive a first radio frequency (RF) input signal and to amplify the first RF signal on a first path during a first mode of the circuit;
• a second amplifier configured to receive a second RF signal and to amplify the second RF signal on a second path during a second mode of the circuit, wherein the second path and first path intersect at a junction node;
• a switching device coupled with the second amplifier to switch the circuit between the first mode and the second mode;
• a matching circuit coupled between the junction node and the second amplifier to convert an impedance at an output terminal of the second amplifier to an impedance at the junction node at a fundamental frequency of the RF signal and to present an open circuit at a third harmonic of the first RF signal, the matching circuit including:
• an inductor coupled between an output terminal of the second amplifier and the switch;
• a first capacitor coupled in parallel with the inductor;
• and
• a second capacitor coupled between the output terminal of the second amplifier and a ground terminal.

A system comprising:

• one or more antennas;
• a transceiver;
• and
• a power amplification module coupled with the one or more antennas and the transceiver, the power amplification module configured to receive radio frequency (RF) signals from the transceiver and provide amplified RF signals to the one or more antennas, wherein the power amplification module is switchable between a high-power mode and a low-power mode, and wherein the power amplification module includes:
• a high-power amplifier configured to receive a first RF signal and to amplify the first RF signal on a first path during the high-power mode;
• a low-power amplifier configured to receive a second RF signal and to amplify the second RF signal on a second path during the low-power c rode, wherein the first and second paths intersect at a junction node;
• a switch coupled between the low-power amplifier and the junction node, the switch configured to be dosed during the low-power mode and open during the high-power mode;
• and
• a matching circuit coupled between the low-power amplifier and the junction node to:
• convert an output impedance at the low-power amplifier to a junction impedance at the junction node at a fundamental frequency of the second RF signal;
• and
• present an open circuit at a third harmonic of the first RF signal.