Characteristic modes analysis for pattern shaping of handheld platforms

The effects of introducing a phase-shift in the characteristic modes (CMs) of a rectangular conductive plane have been investigated. More in detail, a careful characteristic modes analysis (CMA) has been carried out in the aforementioned conditions to verify the possibility of significantly altering the shape of the overall radiated pattern. Among all the CMs, only two radiating modes (Jn) have been selected to achieve a pattern-reconfiguration ability. In particular, by a weighting linear superposition of only these two radiating modes over the conductive sheet, it is possible to realize a null-steering antenna in a principal plane. As proof of concept, a prototype of the proposed antenna has been realized and measured. The obtained results present a good agreement with the simulations and prove that the proposed design guidelines are reliable and also applicable to other kinds of structures.