The antenna includes at least one group of antenna elements (EA1, EA2, . . . , EAp). Microwaves emitted by a central emitter (EH) reach a particular element (EA1 for example) by passing through a controllable phase shifter (VE1), a laser (LE1) which modulates a carrier light signal at a frequency specific to said antenna element with the microwaves, via an optical deflector (FIE) which injects said light signal into an optical waveguide (GE) which is common to all of the antenna elements in the group, via an optical deflector (FPE) which directs said light signal to a detector which is specific to said antenna element (EA1), and which reconstitutes the microwaves, and via a microwave amplifier (AE1) which applies the microwaves to said antenna element. The system is applicable to telecommunications and to radar.