An electronic device may be provided with wireless circuitry that includes antenna structures used to determine the position and orientation of the electronic device relative to external wireless equipment. The electronic device may include a housing having a planar conductive layer, a first slot antenna that includes a first bent slot element in the planar conductive layer, and a second slot antenna that includes a second bent slot element in the planar conductive layer. The first and second bent slot elements may be configured to receive radio-frequency signals at the same frequency. The first and second bent slot elements may have the same shape. The electronic device may include control circuitry configured to measure a phase difference between the radio-frequency signals received by the first and second slot antennas. The control circuitry may identify an angle of arrival of the received radio-frequency signals based on the measured phase difference.