Compact polarisation insensitive wide angular stable triple band absorber for RF energy harvesting, RCS reduction, and sensor applications

Abstract

This paper presents a new compact ultra-thin triple-band absorber which shows near-unity absorption in C, X and Ku-bands. It consists of an inductive stub loaded circular ring resonator and a flower-shaped resonating patch on top of 0.8 mm thin FR-4 grounded dielectric substrate. A transmission line equivalent is proposed, and circuit simulation response is in good agreement with the full-wave analysis. The unit-cell architect's 4fold symmetry makes it polarisation-insensitive for different polarisation angles in the azimuthal plane (? = 0 ) under normal incidence. Its good shows angular stability up to 45 under TE (75 under TM) incidences for all three frequencies. Surface current patterns are analysed at resonant frequencies to illustrate the mechanism behind the electromagnetic absorption. This design's novelty lies in the centre patch's dual-resonating behaviour, making this design compacted one. The absorber has low-profile nature with cell periodicity of 0.163λ L and thickness 0.013λ L , where λ L is the lowest resonating peak wavelength. An X-band conventional MSA is fabricated on a thin FR-4 substrate. In-band RCS reduction (nearly 18 dBsm) of the antenna is verified after loading with the proposed absorber. The absorptivity peaks are optimised such that the same structure would be used in different applications like RF energy harvesting, RCS reduction and sensor applications.

Quad-Band Polarization-Insensitive Square Split-Ring Resonator (SSRR) with an Inner Jerusalem Cross Metamaterial Absorber for Ku- and K-Band Sensing Applications

“…The major limitations of the resonator base of MMAs are the narrow low values of the absorption band, which reduce the operating range and accuracy of the MMA. This limitation can be overcome by multi-band MMAs, which have an increased operating range and efficiency [14,[29][30][31]. Multiband perfect absorption with full programmability of the absorbed bands was demonstrated in [14] by in situ tuning of an overmoded scattering system equipped with a programmable metasurface to the desired functionality.…”

“…Multiband perfect absorption with full programmability of the absorbed bands was demonstrated in [14] by in situ tuning of an overmoded scattering system equipped with a programmable metasurface to the desired functionality. Moreover, polarization-insensitive behavior is also an important feature of MMAs, resulting in stable absorption properties at different polarization angles, which improves the usability of MMAs at different polarization values [29,32,33]. MMAs have the potential used for sensing applications in the microwave range.…”

“…MMAs have the potential used for sensing applications in the microwave range. Various devices have been proposed for different sensing applications, such as permittivity sensors, refractive index sensors, grin sensors, density sensors, temperature sensor, and glucose sensors [29,30,[32][33][34][35][36][37]. Moreover, K-and Ku-band frequencies can be applied for short-range microwave sensing [32,38,39].…”

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

“…Electromagnetic (EM) wave absorption has gained significance in applications like RF energy harvesting, photo‐detectors, micro‐bolometers, biological image sensing, EM shielding, and radar cross section (RCS) reduction in stealth technology 1 . Salisbury screen was the first traditional microwave absorber, 2 consisting of a flat resistive sheet coated on a ground dielectric spacer.…”

Dual-Band X-Shaped Absorber Design for Sensor Applications

“…In practical applications, they are expected to have physical properties such as ease of manufacture, compactness, reusability, low cost, and electrical properties such as high sensitivity and quality factor. Many absorber designs of various types and specifications that can meet the principal requirements of the sensor applications have been reported in the literature [9][10][11][12][13][14][15][16][17][18][19][20]. In most of these studies, SRRs have been used as the primary absorbing structure, allowing high selectivity and quality factors due to their inherent resonant characteristic [10][11][12][13][14][15][16].…”