A transceiver includes an antenna, an impedance adjustment device, an RF (Radio Frequency) front-end circuit, a storage device, and a processor. The antenna receives an RF signal. The impedance adjustment device is coupled to the antenna, and includes a plurality of branch circuit with different impedance values and a switch module. The processor is coupled to the RF front-end circuit and controls the switch modules. In a comparison mode, the switch module selects to connect to the branch circuits individually, and the processor detects each RSSI (Received Signal Strength Indications) value corresponding to the branch circuit and records all of the RSSI values to the storage device respectively. In the comparison mode, the processor further compares the RSSI values to for highest one. Finally, the switch module selects the branch circuit corresponding to the highest RSSI value as a transmission branch.