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 \(\lambda_L\)/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 20 dB of RCS reduction.  It exhibits potential applications in both the field of stealth and the elimination of antenna wavefront blockage.