Patent ID: 7844231

Claim:
An apparatus in a Time Division Duplex (TDD) wireless communication system, the apparatus comprising: two 90° hybrid couplers, each for separating a signal input through any one of four input/output ports into two signals having a phase difference of 90° between them and outputting the two signals through two ports of the four input/output ports, and each for coupling two signals input through two ports of the four input/output ports and outputting the coupled signal through one of the four input/output ports that varies depending on a phase difference of the two signals; and a phase converter block coupled between the two 90° hybrid couplers, the phase converter block for, in a transmission mode, varying phases of two signals received from the first 90° hybrid coupler among the two 90° hybrid couplers by substantially the same value and outputting the varied two signals to the second 90° hybrid coupler, and for, in a reception mode, varying phases of two signals received from the second 90° hybrid coupler among the two 90° hybrid couplers by a difference value and outputting the varied two signals to the first 90° hybrid coupler.