In retrodirective wireless power delivery environments wireless power receivers generate and send beacon signals that are received by multiple antennas of a wireless power transmission system. The beacon signals provide the charger with timing information for wireless power transfers and also indicate directionality of the incoming signal. As discussed herein, the directionality information is employed when transmitting in order to focus energy (e.g., power wave delivery) on individual wireless power receiver clients. Techniques are described herein for reducing the burden of sampling the beacon signals across the multiple antennas and determining the directionality of the incoming wave. In some embodiments, the techniques leverage previously calculated values to simplify the receiver sampling.