FRONT END MODULE AND A COMMUNICATION TERMINAL, ESPECIALLY IN RELATION TO REDUCING A HARMONIC FREQUENCY DURING TRANSMISSION RADIATED FROM AN ANTENNA IN A WIRELESS COMMUNICATION APPARATUS FOR CONVERTING VARIOUS TRANSCEIVING SIGNALS BY A SWITCH CIRCUIT CONNECTED TO THE ANTENNA

摘要

PURPOSE: A front end module and a communication terminal are provided to offset the third harmonic frequency going toward an antenna direction by being generated from a switch circuit with the second harmonic frequency going toward the antenna by being generated from a power amplifier, thereby sufficiently suppressing the harmonic frequency radiated from the antenna. CONSTITUTION: A switch circuit(SW), a low pass filter(LPF), a power amplifier(PA), and phase shifters(21,22) are integrated as a front end module. A common port of the switch circuit(SW) is connected to an antenna terminal(31), one of two conversion ports of the switch circuit(SW) is connected to a receiving terminal(32), and the other one of the ports thereof is connected to an output side of the power amplifier(PA) via the phase shifter(21), the low pass filter(LPF), and the phase shifter(22), respectively. An input side of the power amplifier(PA) is connected to a transmitting terminal(33) from a transmission system(20). A matching circuit(23) is embedded in the output side of the power amplifier(PA).