Spherical Modes Driven Directional Modulation With a Compact MIMO Antenna

In this letter, a compact beamsteering multiple-input-multiple-output (MIMO) antenna is proposed for directional modulation applications. A generalization of the principle presented and by exploiting antenna's unidirectional capability within entire azimuth plane, system realizes secure steerable transmissions in direction legitimate receiver, with low bit error rate $\boldsymbol{10^{-5}}$ , while high notation="LaTeX">$\boldsymbol{10^{-1}}$ seen outside desired regions. Numerical experimental verifications are carried out to validate concept comparisons circular arrays conducted, revealing that achieves comparable performance but up notation="LaTeX">$\boldsymbol{35\%}$ notation="LaTeX">$\boldsymbol{71\%}$ reduction diameter profile, respectively. The method as good candidate enhance security small Internet Things (IoT) devices.