In this article, an X-band metasurface is designed and this metasurface array is used as an instrument to increase gain & reduce radar cross section of circularly polarized X-band MIMO antenna through super-state and under-state positioning of array respectively. Absorbance of the metasurface to the intended frequency band (i.e., 6.75GHz-14.0GHz) is more than 90.0%. Metasurface is designed on FR-4 substrate height (Hs) 3.1mm with unit cell dimension of 7.95×7.95×3.1mm3 (0.265λo×0.265λo×0.103λo) at 10GHz. The proposed antenna is also designed on FR-4 substrate with dimensions of 29×23×1.6mm3 (0.966λo×0.766λo×0.0.053λo) at 10GHz. The super-state and under-state positioning of metasurface array over MIMO antenna is increased the gain (peak gain 12.6dBi at 11GHz) and reduced the mono-static RCS (18dBm2) across the band respectively. The characteristic of the antenna is likewise verified by its s-parameters, radiating efficiency, gain and diversity parameters for the intended band. The simulated & measured results are having better harmony which exhibits suitability of the proposed designs for IoT over satellite, military application, and also useful to identify blood clouting in CT-scan application.

In this article, a nona-band metasurface with unit cell dimensions of 0.038λo×0.038λo×0.019λo is designed on a FR-4 substrate of 1.0mm thickness with 35µm copper cladding. In TE/TM mode, the absorbance is greater than 99% at the intended frequency bands (i.e., 5.76, 8.6, 12.68, 14.38, 17.05, 17.94, 19.20, 20.88, 22.62, and 23.62GHz), and its reflectivity is almost zero. Results indicated that the metasurface is found to extremely independent on the angles of polarization of the incident wave and the absorber is almost insensitive to the incident angle (0° – 90°) for TE/TM modes. The unit cell of metasurface is having negative permittivity, near zero permeability and negative refractive index at all intended bands which confirm exotic properties of the metasurface. The metasurface is having high quality-factor (Q = 72) at 5.76GHz frequency therefore, this metasurface is also useful for dielectric sensing application in intended bands.[1]The metasurface’s unparalleled properties make it suitable for EMI shielding, sensing applications in the C, X, and Ku-bands, the reduction of mono-static RCS, the improvement of isolation in MIMO antennas, and the reduction of unintended noise produced by copper components used in satellite and RADAR communication.

In this paper, a rectangular-shaped wideband dielectric resonator Graphene inspired electronic band gap (EBG) based complementary split ring resonator (CSRR) loaded miniaturized THz MIMO antenna is designed having a dimension of 56×56×3.6μm3 is designed on a Roggers RO3035 substrate with a relative permittivity of 3.6 and loss tangent 0.0015. This antenna works in the range of 6.0THz-12.5THz (70.76%) with a peak gain of 7.68 dBi. This composite DRA materials having Silicon (εr = 11.1) based cylindrical dielectric and cylindrical Graphene disk to be stacked on rectangular radiated antenna having height of 13.5µm and 0.2µm to improve the impedance bandwidth as well as gain of the antenna from 5.24dBi to 7.68dBi. Firstly single-element gold plated rectangular shaped antenna is transformed into a two-element MIMO antenna with mushroom-shaped EBG structure is deployed for improving the isolation between two antenna elements as well as to improve the front-to-back ratio (FBR). CSRR is loaded to obtained band notch characteristics for avoiding the interference between near wireless devices in the span of 10.6-10.8THz. Graphene disk having 3µm height put on Silicon (εr = 11.1) based cylindrical DRA provides high gain and improved the impedance bandwidth for achieving wide bandwidth from 6.0THz-12.5THz. The proposed MIMO Antenna performance has been judged by antenna parameters like gain, return loss, isolation between two antenna elements, diversity parameters like ECC, DG, TARC, Mean Effective Gain (MEG), Channel Capacity Loss (CCL) and found proposed DRA-MIMO antenna suitable for wide band nano/optical communication in 6G for IoT and bio-medical sensing application.