Full-duplex transceivers are typically used in both RADAR and RFID applications, as this architecture transmits and receives at the same time, a problem referred to as self-interference occurs. The transmitted signal leaks into the receiver and the phase noise of the leaked signal interferes with the returned receive signal. This thesis proposes, analyzes and measures a novel method of self-interference cancellation in full-duplex transceivers through the use of an IQ mixer and system design constraints. The original Local Oscillator of the transmitter is coupled and used for down conversion, if the system can be assumed to be linear, and time-invariant the phase noise of the self-interference can be estimated, and significantly reduced. This method was shown to achieve cancellation of up to 32.6 dB, however theoretically the limits of this method are constrained by the sensitivity of the measurement and matching systems used.