Patent ID: 8705412

Claim:
An apparatus for protecting receive circuits in a Time Division Duplexing (TDD) wireless communication system, the apparatus comprising: a TDD controller for controlling transmission and reception modes according to transmission and reception intervals; a transmitter for power-amplifying and outputting a Radio Frequency (RF) signal in the transmission mode under control of the TDD controller; and a Transmit/Receive Antenna Switch (TRAS) for, in the transmission mode, forwarding a signal of the transmitter to an antenna feed line under the control of the TDD controller and for absorbing an output signal of the transmitter flowing to the receive circuits using a pass and reflection block positioned in a reception path, and, in the reception mode, for forwarding a signal fed from the antenna feed line to the receive circuits under the control of the TDD controller, wherein the pass and reflection block comprises: a first 90° hybrid coupler for splitting an input signal fed from the TRAS into two signals being half of the input signal and having a phase difference 90°, and for outputting the two signals to different ports; a first reflection block for, in the transmission mode, reflecting the signal output from the first 90° hybrid coupler through a first port, to the first port, and, in the reception mode, for passing the signal output from the first 90° hybrid coupler through the first port; a second reflection block for, in the transmission mode, reflecting the signal output from the first 90° hybrid coupler through a second port, to the second port, and, in the reception mode, for passing the signal output from the first 90° hybrid coupler through the second port; a second 90° hybrid coupler for combining the two signals output from the first reflection block and the second reflection block and for sending the combined signal to the receive circuits; and a termination unit for absorbing the reflected signals fed from the first 90° hybrid coupler.