Design of Invisibility Cloak Assisted by 3D Microwave Circuits

A invisibility cloak designed with three-dimensional (3D) microwave circuit assistance is proposed in this letter. Conformally wrapped around a square tube, the cloak achieves substantial radar cross-section (RCS) reduction while preserving the integrity of the incident electromagnetic wavefront. A microwave circuit model in 3D space is proposed, and combined with the current distribution of full-wave simulation, the mechanism of the proposed structure is revealed. The cloak is fabricated on a conformal plastic substrate via an industrially compatible electroplating process, and the thickness is only λL/35 in the lowest operating frequency. Periodic-structure simulations, RCS simulations, and experimental RCS measurements exhibit good mutual agreement and closely match the 3D circuit-model calculations. In the 3.1-3.7 GHz frequency band, the cloak delivers over 10 dB of RCS reduction. It exhibits potential applications in both the field of stealth and the elimination of antenna wavefront blockage