Patent attributes
An electronic device may be provided with wireless circuitry that includes an antenna. Control circuitry may perform closed loop tuning adjustments on the antenna. For example, the control circuitry may adjust a tunable component to tune the antenna to a first tuning setting. The control circuitry may gather impedance values from the antenna while tuned to the first tuning setting and may process the impedance values to determine whether to tune the antenna to a second tuning setting. If the impedance values lie within a predetermined complex impedance region, the control circuitry may tune the antenna to the second setting. If the impedance values lie outside of the region, the control circuitry may continue to gather impedance values using the first setting. These operations may compensate for detuning of the antenna due to proximity of a user regardless of how the electronic device is held during operation.