Aspects of the disclosure provide a method of adjusting a plurality of phase shifters of an OPA. The method may include identifying, by one or more processors, one or more first subsets of phase shifters of the plurality of phase shifters based on an orthogonal set of functions; performing, by the one or more processors, one or more first dithers on the one or more first subsets of phase shifters of the plurality of phase shifters using one or more first frequencies of a predetermined set of frequencies; determining, by the one or more processors, one or more first corrections based on a first power output of the OPA resulting from the one or more first dithers; and adjusting, by the one or more processors, the one or more first subsets using the one or more first corrections, the adjustment resulting in a first set of corrected phase shifter values.