A system and method for spreading and de-spreading a signal at an antenna. A Direct Spatial Antenna Modulation (DSAM) system makes use of the spatial characteristics of a radiating antenna structure to directly alter a signal transmitted or received by the radiating structure. When used for transmitting data, a data stream maps a signal to different spatial points of excitation in the antenna structure, where each chosen configuration has different radiating characteristics including phase, amplitude, and polarization, which can be used to represent data symbols. A code spreading sequence is applied to switch the output of the DSAM antenna to spatial points in the antenna to spread an input signal. The code spreading sequence is applied to an antenna to de-spread a previously spread signal. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this Abstract.