There are disclosed antenna arrays for portable electronic devices. In one aspect, the antenna array comprises at least two antennas, each antenna comprising at least two radiating elements; and at least two control networks each comprising a plurality of impedance matching circuits and RF switches, each antenna being connected to a respective control network. Each control network connects the radiating elements of its respective antenna to a single RF port. Each antenna element is connected to a respective first RF switch in its respective control network allowing selection between different ones of the plurality of impedance matching circuits. Each port is connected to a respective second RF switch in its respective control network allowing selection between different ones of the plurality of impedance matching circuits. The impedance matching circuits are connected between the first RF switches and the second RF switch in each control network. In another aspect, the antenna array comprises a plurality of leaky-wave antennas; a plurality of control networks each comprising a plurality of impedance matching circuits and RF switches, each leaky-wave antenna being connected to a respective control network; and a digital control processor configured to send control signals to the control networks so as to control operation of the leaky-wave antennas. Each control network connects its respective leaky-wave antenna to a single RF port.