First and second transmission paths are provided between a first port to
which an antenna is connected and a second port to which a transceiving
circuit is connected. First to fourth reception filters, an amplifier
circuit, and first to fourth hybrid circuits are provided on the first
transmission path. A reception signal from the antenna is transmitted
from the first port to the second port via the first hybrid circuit, the
first and second reception filters, the second hybrid circuit, the
amplifier circuit, the third hybrid circuit, the third and fourth
reception filters, and the fourth hybrid circuit in this order. This
reception signal does not return to the amplifier circuit, whereby the
reception signal is prevented from oscillating due to positive feedback.