for a multiband operation or in another preferred embodiment the sfc curve such as 25 defines the perimeter of an aperture 33 on the patch 30 fig1 such an aperture contributes significantly to reduce the first resonant frequency of the patch with respect to the solid patch case which significantly contributes to reducing the antenna size said two configurations the sfc slot and the sfc aperture cases can of course be use also with sfc perimeter patch antennas as for instance the one 30 described in fig1 at this point it becomes clear to those skilled in the art what is the scope and spirit of the present invention and that the same sfc geometric principle can be applied in an innovative way to all the well known prior art configurations more examples are given in fig1 16 17 and 18 fig1 describes another preferred embodiment of an sfc antenna it consists on an aperture antenna said aperture being characterized by its sfc perimeter said aperture being impressed over a conducting ground plane or ground counterpoise 34 said ground plane of ground counterpoise consisting for example on a wall of a waveguide or cavity resonator or a part of the structure of a motor vehicle such as a car a lorry an airplane or a tank the aperture can be fed by any of the conventional techniques such as a coaxial cable 11 or a planar microstrip or strip line transmission line to name a few fig1 shows another preferred embodiment where the sfc curves 41 are slotted over a wall of a waveguide 47 of arbitrary cross section this way and slotted waveguide array can be formed with the advantage of the size compressing properties of the sfc curves.