Abstract: A transmission/reception system for electromagnetic signals such as radar operates with a non-lineaar/non-planar array of passive radiating/reception elements, and a smaller number of active transmission/reception (T/R) modules which generate and receive coded or uncoded RF power and/or electromagnetic signals within a desired portion of the electromagnetic spectrum. The active T/R modules are switched between respective pluralities of the passive radiating/reception elements, so that each module is connected to only one element at a time. The switching is controlled so that the T/R modules are connected to desired patterns of passive elements in succession. The passive elements are arranged in a plurality of sectors, with the active T/R modules each connected to a respective single passive element in each sector.