Design and verification of a polarization-insensitive and angel-stable tunable electromagnetic scattering structure

It is a new development direction in the field of electronic countermeasures to achieve stealth and camouflage by controlling the amplitude and phase of the scattering wave of the imaging radar. In this paper, a S-band polarization-insensitive and angel-stable tunable electromagnetic scattering structure (ESS) is proposed, which consists of metallic grid and square patches loaded with varactor diodes on the top layer and a feed grid connected by vias on the bottom layer. The broadband miniaturization of the ESS with a unit cell dimension of λ₀/10 is realized by the design of diodes capacitance loading, equivalent inductance strengthening and backside feed inductance. Continuous tunning in the range of 1.98 GHz to 3.91 GHz can be realized by changing the external bias voltage, and the relative tuning range is 69.5%. In the range of 2.27−3.83 GHz, the amplitude variation range of the reflected wave is more than 15 dB, and the maximum phase variation range is 269°. In addition, the overall performance remains stable under ±60° incidence and TE / TM polarization, which has good prospects for application in the field of radar imaging interference.