Seeing the rising applications of metamaterial in sensing and imaging, satellite communications, it becomes evident to design a high-gain microstrip patch antenna. To support these applications, this paper proposes a 7 x 7 array of planar novel metamaterial unit cells used as a superstrate to enhance the gain of microstrip patch antenna operating at 11.2 GHz. This proposed metamaterial structure yields a very low (near zero) value of effective refractive index at 11.2 GHz. Hence, the superstrate behaves as a near zero-indexed-medium (NZIM) around this frequency. NZIM superstrate are very popular because of their ability to focus the radiation and by utilizing this property, a significant gain enhancement has been achieved in the usage of patch antennas. Numerical simulations have been conducted using the CST Microwave studio, and obtained results corroborate that NZIM superstrate when suspended over a microstrip patch antennas significantly improves the gain around the value of 7.5 dB at 11.2 GHz, and efficiency is also improved

Seeing the recent rise in applications of RFID tags in industrial internet of things (IIoT), it become very evident to design an efficient and compact antenna which is able to satisfy the uprising IoT demands. This work presents a new 3D quasi-isotropic electrically small antenna (ESA) for RFID applications in the 2.4 GHz band. The proposed antenna is designed on a single perfect electric conductor (PEC) sheet by loading an inverted L-shaped slot. An opened aperture is excited to realize magnetic dipole characteristics to achieve a quasi-isotropic radiation pattern in 3D spatial coverage. The overall volume of the prototype is O.18Ax0.07Ax0.0096A nm3; here, ? is the free space wavelength that corresponds to operating frequencies. The proposed antenna offers a 30MHz (2.42-2.45 GHz) impedance bandwidth centered at 2.43 GHz. The antenna exhibits a quasi-isotropic radiation pattern with a maximum efficiency of 85%, which makes it suitable for RFID applications.

This work presents a novel frequency reconfigurable electrically small antenna (ESA) with a quasi-isotropic radiation pattern for ISM band applications within the 2.4 GHz band. The key contribution of this work is that a split ring resonator (SRR) is used parasitically with the electric dipole to realize a magnetic dipole-type radiation pattern. In addition, the proposed configuration is further configured with two p-i-n diodes to facilitate frequency reconfigurability to the antenna within the 2.4 GHz band. The SRR is arranged orthogonally with an electric curved dipole to achieve a uniform or quasi-isotropic radiation pattern in 3D spatial coverage. The overall size of the fabricated prototype is 0.13?×0.13? mm2; here, ? is the free space wavelength that corresponds to operating frequencies. The proposed antenna offers 40MHz bandwidth centered at 2.44GHz when the diodes (D1 & D2) are ON and a 30MHz bandwidth centered at 2.47GHz when the diodes (D1 & D2) are OFF. In both states, the antenna exhibits a quasi-isotropic radiation pattern with over 60% efficiency