A low-profile, compact, four-element, eight-port multiple-input--multiple-output and diversity antenna for 5G Internet of Things and cellular handheld applications is presented in this letter. This antenna structure contains four antenna elements, which are same in its configuration. The antenna ground dimensions are taken similar to a modern mobile handset, i.e., 60 mm × 120 mm. The four antenna elements are situated at four corners of antenna ground structure. Each antenna element has two feeding ports, thus making a total of eight-port antenna. A single antenna element has two feeding plates, which are placed perpendicular to one another so that they become cross polarized, thus exploiting polarization diversity, whereas spatial diversity also exists between different antenna elements. For reducing mutual coupling between different antenna ports, slots are cut in ground plane, including a small strip etched along the entire length of ground plane and rectangular slots cut in ground plane under every antenna element. The minimum bandwidth attained by all eight ports for S ₁₁ < –10 dB is more than 1.4 GHz from 2.4 GHz to more than 3.8 GHz, which testify that it covers majority of frequency bands allocated for 5G sub-6 GHz spectrum. The isolation obtained between different ports has a minimum value of –13 dB, and the maximum value goes below –30 dB. For the covered frequency bands by this antenna structure, the correlation coefficient is found to be below 0.03, whereas the measured peak gain is in the range of 3.2--5 dB.

This letter presents a wide-angle scanning multibeam planar inverted-E antenna (PIEA) array for vehicle-to-everything communication. The compact four-element PIEA array is designed with 0.3λ _o spacing, which achieves 90 $^{\circ}$ wide-angle scanning when a 135 $^{\circ}$ phase shift is applied obtained using a 4 × 4 Butler matrix (BM). The closeness of the array elements causes high mutual coupling and high cross polarization at wider scan angles. Therefore, three novel techniques are employed to overcome the high cross polarization and mutual coupling between the antenna elements in this array. To feed the antenna array, a low-cost miniaturized beamforming 4 × 4 BM circuit is designed without the use of phase shifters and conventional crossovers. The total dimensions of the compact PIEA array are just 0.456λ ₀ × 1.12λ ₀ × 0.036λ ₀ , while the overall dimensions of the multibeam array, including BM, are 2.731λ ₀ × 2.2λ ₀ × 0.046 λ ₀ . This multibeam array achieves for the first time the wide-angle scanning angles of ±87 $^{\circ}$ with a 3 dB beam scanning range of ±120 $^{\circ}$ along with the scanning angles of ±20 $^{\circ}$ . This array design can be scaled to use as an antenna array for millimeter-wave applications.

5G, the fifth generation of wireless communications, is focusing on multiple frequency bands, such as 6 GHz, 10 GHz, 15 GHz, 28 GHz, and 38 GHz, to achieve high data rates up to 10 Gbps or more. The industry demands multiband antennas to cover these distant frequency bands, which is a task much more challenging. In this paper, we have designed a novel multiband split-ring resonator (SRR) based planar inverted-F antenna (PIFA) for 5G applications. It is composed of a PIFA, an inverted-L parasitic element, a rectangular shaped parasitic element, and a split-ring resonator (SRR) etched on the top plate of the PIFA. The basic PIFA structure resonates at 6 GHz. An addition of a rectangular shaped parasitic element produces a resonance at 15 GHz. The introduction of a split-ring resonator produces a band notch at 8 GHz, and a resonance at 10 GHz, while the insertion of an inverted-L shaped parasitic element further enhances the impedance bandwidth in the 10 GHz band. The frequency bands covered, each with more than 1 GHz impedance bandwidth, are 6 GHz (5–7 GHz), 10 GHz (9–10.8 GHz), and 15 GHz (14-15 GHz), expected for inclusion in next-generation wireless communications, that is, 5G. The design is simulated using Ansys Electromagnetic Suite 17 simulation software package. The simulated and the measured results are compared and analyzed which are generally in good agreement.

A resistively loaded wideband slotted patch antenna with optimized performance on lower frequencies is proposed for ground-penetrating radar (GPR) applications. The proposed design is backed by an optimized reflector composed of a periodic array of square loop elements, which enhances the antennas gain and directivity. The antenna shows good radiation characteristics and ease of integration with the GPR systems. The proposed structure features a compact size and wide bandwidth covering from 0.6 to 4.6GHz. The peak gain of 7 dBi is achieved. The fabricated prototype of the antenna along with an integrated optimized reflective surface has overall dimensions of 18×22×5cm³. The measured results validate the antennas performance in both free space and sandy medium, which enlighten its use for GPR applications.

This study examines the effects of different burning temperature on the chemical and microstructure properties of WSA. In many parts of the world due to non-availability of proper technology, the farmers generally burn wheat straw after acquiring grains, which causing environmental pollution with fire hazards at farm level and loss valuable commodity. In this research, the influence of different temperature on locally available Wheat Straw in Province KP, Pakistan was study. This research aim to find optimum temperature and burning duration of WSA by examine chemical and microstructural properties of WSA at 550^oC for 4 hr, 550^oC for 8 hr and 800^oC for 30 min. The tests results were categorized through X-ray Diffraction (XRD), X-Ray fluorescence (XRF) and Fourier Transform Infrared Spectroscopy (FTIR). The result showing the 550^oC for 4 hr contains high amount of (SiO₂+Al₂O₃+Fe₂O₃) and amorphous nature as compared to other samples.

Terbium doped magnesium spinel ferrites (Mg1-xTbxFe2O4) with composition x=0.12, 0.14, 0.16, 0.18 were synthesized via micro-emulsion method followed by synthesis of PVA/Mg1-xTbxFe2O4 composites using in-situ polymerization technique. The structural properties were evaluated using X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR). XRD analysis confirmed the construction of spinel lattice of terbium ferrite whereas FTIR revealed the interactions between ferrite nanoparticles and polyvinyl alcohol matrix. The XRD and FTIR results quite matched with the reported literature. The dielectric and resistivity analyses were performed by determining dielectric parameters and current-voltage measurements. The values of dielectric constant, dielectric loss and tan ? were found to be inversely proportional to the frequency under the ambient electric field at room temperature but became constant at higher frequency values. The lower values of dielectric constant of terbium incorporated magnesium ferrite polymer composites (MgFe2O4/PVA) are attributed to hindrance in ‘electron exchange mechanism’ created by lockup between iron and terbium ions. The resistivity values of all the composites were found from 2.5x109 ?cm to 18.8x109 ?cm which showed a non- linear behavior.