A transmitter system for an array of antenna elements, said transmitter system comprising: a bidirectional signaling, BDS, network including a first network for carrying a first carrier signal and having a second network for carrying a second carrier signal, and having a set of n phase synchronous location pairs, a i, b i, each corresponding to a location a i on the first network and a location b i on the second network; and a plurality of tunable transmitter circuits, each for driving a corresponding different antenna element of the array of antenna elements, wherein each tunable transmitter circuit of the plurality of tunable transmitter circuits has an output line for carrying an output signal and first and second input lines electrically connected to the first and second tree networks of the BDS network at locations of a corresponding one of the set of phase synchronous locations pairs, and comprises: a multiplier having a first input electrically connected to the first input line of that tunable transmitter circuit; a phase setting circuit having a control input for receiving a phase control signal, said phase setting circuit electrically connected to said multiplier for controlling the phase of the output signal of that tunable transmitter circuit; and an amplitude setting circuit within a signal path extending between the output of the multiplier and the output line of the tunable transmitter circuit and having a control input for receiving an amplitude control signal, said amplitude setting circuit for controlling the amplitude of the output signal of that tunable transmitter circuit. a bidirectional signaling, BDS, network including a first network for carrying a first carrier signal and having a second network for carrying a second carrier signal, and having a set of n phase synchronous location pairs, a i, b i, each corresponding to a location a i on the first network and a location b i on the second network; and a plurality of tunable transmitter circuits, each for driving a corresponding different antenna element of the array of antenna elements, wherein each tunable transmitter circuit of the plurality of tunable transmitter circuits has an output line for carrying an output signal and first and second input lines electrically connected to the first and second tree networks of the BDS network at locations of a corresponding one of the set of phase synchronous locations pairs, and comprises: a multiplier having a first input electrically connected to the first input line of that tunable transmitter circuit; a phase setting circuit having a control input for receiving a phase control signal, said phase setting circuit electrically connected to said multiplier for controlling the phase of the output signal of that tunable transmitter circuit; and an amplitude setting circuit within a signal path extending between the output of the multiplier and the output line of the tunable transmitter circuit and having a control input for receiving an amplitude control signal, said amplitude setting circuit for controlling the amplitude of the output signal of that tunable transmitter circuit. a multiplier having a first input electrically connected to the first input line of that tunable transmitter circuit; a phase setting circuit having a control input for receiving a phase control signal, said phase setting circuit electrically connected to said multiplier for controlling the phase of the output signal of that tunable transmitter circuit; and an amplitude setting circuit within a signal path extending between the output of the multiplier and the output line of the tunable transmitter circuit and having a control input for receiving an amplitude control signal, said amplitude setting circuit for controlling the amplitude of the output signal of that tunable transmitter circuit.