It is possible to match the impedance of an antenna without directly measuring the phase. This is advantageous as it reduces the cost, and complexity, of wireless transceivers. In particular, the phase component of an antenna's reflection coefficient can be estimated based on return loss measurements. For example, a transceiver may measure an initial return loss of the antenna, adjust the impedance of at least one tunable element, and then measure one or more adjusted return losses of the antenna. The phase of the reflection coefficient can be estimated based on a difference between the initial return loss and the one or more adjusted return losses.