Wideband in-phase/quadrature imbalance compensation using finite impulse response filter

The authors proposed an in-phase/quadrature (I/Q) imbalance compensation technique for wideband digital receiver applications. An I/Q channel-based receiver can double the receiver working bandwidth. However, the amplitude/phase imbalance of an imperfect hybrid coupler can generate image signals thus reducing the receiver´s instantaneous dynamic range. They developed a finite impulse response filter-based technique to mitigate deleterious effects because of the amplitude/phase imbalance. Both simulations and experiments were conducted to verify validity of the developed algorithm. The simulation and experiment results show that the proposed imbalance mitigation technique can reduce image signal powers by more than 24 dB or down to noise level. A receiver system level simulation is also conducted to demonstrate the practicality of the proposed imbalance mitigation method.