An algorithm to evaluate wide-band quadrature mixers

As wide-band wireless communications become increasingly prevalent, evaluation of balance among quadrature mixer ports, in terms of carrier phase offset, gain mismatch, and IQ skew, becomes essential. Due to the difficulty of separating skew, gain imbalance and carrier phase offset, evaluation, such as by taking measurements while calibrating, is time consuming. For this reason, test is often performed using a composite value, without separation of error factors. This paper describes an algorithm for performing accurate measurements while enabling separation among quadrature mixer gain imbalance, carrier phase offset, and skew. Thanks to the short test time of the proposed method, it can be applied during high volume production testing.