Broadband linear‐cross and circular‐circular polarizers with minimal bandwidth reduction at higher oblique angles for RCS applications

Abstract

In this work, broadband linear to cross and circular to circular polarization converter for K and Ka-band applications is proposed. The metasurface comprises a novel H-shaped unit cell printed on 1.2 mm thin FR-4 grounded dielectric substrate. It exhibits 90% polarization conversion ratio (PCR) over a bandwidth of 22.26 GHz (17.97-40.23 GHz) with 76.5% FBW maintaining a minimal PCR of 92.5%. The converter also maintains handedness for circularly polarized incident wave. Surface current distributions at different resonant frequencies are analyzed to illustrate the reason behind the broadband behavior.The converter design is simple with the cell periodicity of 0.209λ o and thickness of 0.071λ o , where λ o is the free-space wavelength corresponding to the lowest frequency of the band. Monostatic and Bistatic RCS analysis of the designed converter is performed, demonstrating greater than 10 dBsm RCS reduction over all the frequency range. It shows 16 to 30 dBsm at resonant

A novel broadband l inear‐cross and l inear‐circular reflective polarizer based on interdigital capacitance loaded dipole for radar cross‐section applications

“…The reflected field would be in negative x‐ direction if and . Due to the orthotropic anisotropic nature of the proposed polarizer, it is noteworthy to mention that this design can also maintain handedness for circular polarization over the same frequency range as linear‐cross conversion 2 …”

“…From Figure 8(A,D), it can be seen that the surface currents of the top FSS and ground pattern are in phase at 18.8 GHz, which means the resonance that occurred here resembles the electric dipole. For the other two higher frequencies, 26.6 and 35.8 GHz, these currents are out of phase, resembling the magnetic dipole resonance 2,5,22 . The combination of electric and magnetic resonance would be responsible for linear to cross broadband polarization conversion from 17.02 to 37.30 GHz.…”

“…Electromagnetic (EM) wave polarization refers to the electric field oscillation direction at a fixed point in space in a plane perpendicular to the direction of propagation 1 . Since the polarization is an essential feature of EM wave, controlling and manipulation of polarization states have potential in applications like radar cross‐section (RCS) reduction, 2 mutual coupling reduction between antennas, 3 countervailing Faraday effect in satellite communications, 4 and changing the polarization of the transceiver without altering the input complex feed networks 5 . Conventionally, the polarization conversion is achieved by the anisotropy that exists in nature available crystals called birefringence phenomena, 6 chirality, 7 and circular dichroism 8 .…”

“…Zhang et al 19 proposed a structurally tunable closed fish‐scale (meandering type) reflective type polarization converter for Ku‐band applications. A 45° oriented H‐shaped dipole‐based reflective polarizer is proposed to perform linear‐cross conversion with greater than 90% polarization conversion ratio (PCR) efficiency for K and Ka‐band applications 2 . In addition to that, it can also maintain circular polarization handedness over the broadband due to the orthotropic‐anisotropy property of this structure.…”

Broadband polarization insensitive wide angular stable dual‐split square ring circuit analog absorber for radar cross section and electromagnetic interference shielding applications

“…On the other hand, metamaterials are artificial periodic constructs enabling the control of the effective permittivity and permeability values as a homogeneous medium. 7 Landy et al proposed the first perfect metamaterial absorber (MMA) using an I-shaped electric field-driven LC resonator printed on the transmission line-backed dielectric substrate, exhibiting the near-unity absorption at X-band. 8 Exploiting the electrical and magnetic resonance would lead to the absorption phenomena in these structures.…”