A broadband microwave cross-polarization-conversion (CPC) metasurface is designed, simulated, fabricated, and tested. The metasurface consists of coupled split-ring-resonators (SRRs) with two splits in each SRR and is designed on an FR4 dielectric substrate backed by a metallic ground plane. An efficient CPC, both for normal as well as for oblique incidence, is achieved with 3 dB fractional bandwidth of 73% from 5 to 10.8 GHz. This wideband polarization conversion results from multiple plasmonic resonances occurring at three neighboring frequencies. Owing to the sub-wavelength unit cell size and symmetric structure of the coupled SRRs, the response of the metasurface is independent of the polarization and incidence angle of the incoming wave, which makes it a potential candidate for many practical applications. The proposed design is validated both numerically and experimentally. Experimental results are found to be in good agreement with simulations.

An ultrathin single-layer metasurface manifesting both linear cross-polarization conversion (CPC) and linear-to-circular polarization (LP-to-CP) conversion in X-band is presented in this research. The designed metasurface acts as a multifunctional metasurface achieving CPC over a fractional bandwidth of 31.6% (8–11 GHz) with more than 95% efficiency while linear-to-circular polarization conversion is realized over two frequency bands from 7.5–7.7 GHz and 11.5–11.9 GHz. Moreover, the overall optimized structure of the unit cell results in a stable polarization transformation against changes in the incidence angle up to 45° both for transverse-electric (TE) and transverse-magnetic (TM) polarizations. The proposed metasurface with simple structure, compact size, angular stability and multifunctional capability qualifies for many applications in communication and polarization manipulating devices.

A low-cost inkjet-printed multiband antenna envisioned for integration into flexible and conformal mobile devices is presented. The antenna structure contains a novel triangular iterative design with coplanar waveguide (CPW) feed, printed on a Kapton polyimide-based flexible substrate with dimensions of 70×70×0.11 mm ³ . The antenna covers four wide frequency bands with measured impedance bandwidths of 54.4%, 14%, 23.5% and 17.2%, centered at 1.2, 2.0, 2.6 and 3.4 GHz, respectively, thus, enabling it to cover GSM 900, GPS, UMTS, WLAN, ISM, Bluetooth, LTE 2300/2500 and WiMAX standards. The antenna has omnidirectional radiation pattern with a maximum gain of 2.1 dBi. To characterize the flexibility of the antenna, the fabricated prototype is tested in convex and concave bent configurations for radii of 78 mm and 59 mm. The overall performance remains unaffected, except a minor shift of 20 MHz and 60 MHz in S11, for concave bending at both radii. The compact, lightweight and conformal design as well as multiband performance in bent configurations, proves the suitability of the antenna for future electronic devices.

This work presents multifunctional metasurfaces for generating focused optical vortices of visible light.

In this letter, a 28.5-bit chipless RFID tag, based on paper substrate and realized using inkjet printing technique is presented. Operating within ultrawideband, the tag occupies a compact size of 2 ×4 cm ² . Focusing on applications requiring time and date identification, a novel encoding technique is presented that allows efficient frequency band allocation based on the number of required instances of time and date variables. A figure of merit (FOM) relating coding capacity and tag dimensions coined as code density is also introduced. A systematic design process followed by simulations and verified through measurements reveal a high code density of 3.56 bits/cm ² for the presented chipless tag.

A wideband snowflake antenna for 28 GHz millimeter-wave communications is proposed. The antenna has a size of 8×5 mm2, fabricated on ultra-thin 0.254 mm substrate. The antenna consists of four small hexagons surrounding a bigger hexagon in order to attain broadband characteristics. Bandwidth response of the antenna is between 25.28–29.04 GHz (13.43% @ 28 GHz), having 3.12 dBi gain and more than 80% of radiation as well as total efficiency. The antenna specific structure is designed such that it gives dual beam over its entire bandwidth without a noticeable shift in its beam directions. For enhanced gain performance, its 4-element array (of size 32×12 mm2) has been fabricated separately to increase its gain upto 10.12 dBi at 28 GHz. The proposed dual-beam antenna and its array has been modelled on thin Rogers substrate to show that its application in millimeter-wave communication equipment is viable.