The commercial success of LTE and the resulting growth in mobile data demand have urged cellular network operators to strive for new innovations. unlicensed spectrum has been proposed allow offload some their traffic by accessing 5 GHz frequency band. Currently, there are three variants operation band, namely LTE-U, licensed assisted access (LAA), MulteFire. This article provides a comparative analysis these explains current regulations band different parts world. We present technical...

A rectangular waveguide is terminated by an infinite conducting flange and radiates into half-space. Modal expansions of the TE TM fields lead to Hermitian forms for incident reflected power ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P_{wg} = P_{wg}^{+} - P_{wg}^{-}</tex> ) in terms corresponding electric field mode amplitude vectors a diagonal admittance matrix [ xmlns:xlink="http://www.w3.org/1999/xlink">Y</tex> ]. The radiated from...

In recent years, metasurface (MTS) arrays have shown promising abilities to control and manipulate electromagnetic (EM) waves through modified surface boundary conditions. The constituent unit elements of a MTS become increasingly complex with rise anisotropic radio-frequency (RF) applications such as beam scanning anomalous reflection/refraction, focusing, polarization conversion in an extremely low-profile. Designing these meta-atoms or metagratings is challenging time-consuming procedure....

The commercial success of LTE makes it the primary standard for 4G cellular technology, and its evolution paves path 5G technology. Furthermore, Unlicensed has been proposed recently to allow network operators offload some their data traffic component carriers operating in unlicensed band. Hence, is critical ensure that system performs effectively even harsh signaling environments both licensed spectrum. This article analyzes effect different levels RF spoofing applied LTE. affects devices...

Long Term Evolution (LTE) networks offer high-speed wireless access to meet the increasing demand in user traffic. LTE technology is also considered for mission-critical networks. Hence, it critical ensure that system performs effectively even harsh signaling environments. This paper analyzes effect of different levels radio frequency (RF) spoofing applied LTE. The simplest form synchronization signal spoofing, where standard-compliant primary and secondary sequences are transmitted by a...

We present a deep learning approach to design tensorial metasurfaces for radio-frequency (RF) applications, such as communications and radar, that have strict radiation requirements. Such intelligent RF surfaces require significant manual tuning of several constituent meta-atom designs realize the required phase shift or polarizability. In this context, meta-atoms comprise multiple layers are considerably more challenging but advantage implementing complex, electromagnetic (EM) responses....

Metasurface-based antenna beam control is defining a new engineering paradigm in radio-frequency applications such as communications, radar, and analog spatial signal processing. Metasurfaces are composite electromagnetic material surfaces that made of subwavelength scattering particles, or meta-atoms, with negligible thickness optimized to waves unprecedented fashions through modified boundary conditions. Conventional metasurface design tedious process requires iteratively solving Maxwell's...

Higher spectral and energy efficiencies are the envisioned defining characteristics of high data-rate sixth-generation (6G) wireless networks. One enabling technologies to meet these requirements is index modulation (IM), which transmits information through permutations indices spatial, frequency, or temporal media. In this paper, we propose novel electromagnetics-compliant designs reconfigurable intelligent surface (RIS) apertures for realizing IM in 6G transceivers. We consider RIS...

Interest in terahertz science has expanded rapidly recent years due largely to the advent of new RF components and fast-pulse optical time domain spectroscopic techniques. The two traditional development communities that border gap - microwave, are beginning converge as we see more wide spread use systems. One technology area where both these can benefit is design realization forms antennas beam forming networks. Both frequency techniques make single mode, broad band antennas. However, most...

A perturbed slot with reconfigurable polarization that allows operation in left-hand circular (LHCP), right-hand (RHCP), or linear (LP) is presented. This antenna topology well suited for wireless communications applications requiring diversity since it provides the ability to switch between three states. design realizable cost-effective printed circuit board technology, making an attractive low-cost personal devices. An element was simulated, built, and tested illustrate electromagnetic...

An analytical method for determining the optimal reflection phase of an electromagnetic band gap (EBG) ground plane to match a low profile dipole antenna is introduced. Image theory used incorporate near field coupling between and plane. The main contribution this paper show that EBG can be determined at discrete frequencies where theoretically perfect return loss occurs. then obtained over wider frequency interest related antenna's given feed impedance height above EBG. resulting as...

Carbon nanotube (CNT) sheet patch antennas are explored through simulation, fabrication, and measurement to evaluate the performance of CNT material as an RF radiator. The thickness was found have a significant impact on radiation antenna due skin depth, with ~ 5.5-dB improvement realized gain achieved when increased from 0.5 μm 5 μm, likely lower surface impedance. μm-CNT exhibited 2.1-dBi total compared 5.6-dBi for baseline copper yielding 3.5-dB reduction attributable substitution. A...

LTE (Long Term Evolution) technology is unarguably becoming the primary standard for 4G cellular networks. But due to tremendous growth in data traffic, Unlicensed Spectrum (LTE-U) has been proposed allow network operators meet such high demands traffic. The initial studies choice of unlicensed frequency bands LTE-U suggested using 5 GHz band. band mainly occupied by different radar systems and 802.11 (Wi-Fi). There are regulations imposed Federal Communication Commission (FCC) each sub-band...

Three-dimensional bootlace lens antennas with two and four focal points can be optimized to produce high-quality scanned beams over a wide field of view. For two-dimensional scanning, the planar feed locus is replaced by curved designed minimize path length errors. Comparisons previous designs demonstrate advantages this distribution. The bifocal shows good scanning performance in both principal orthogonal planes. quadrufocal performs better its plane than plane. It also shown that realized...

The phase errors of the conventional trifocal Rotman lens and its modified quadrufocal designs could be reduced by adopting a non-focal design scheme. produces minimum average for all beam ports rather than achieving zero-phase error only selected focal points. Fundamental models designing optimising typical planar bootlace lenses are reviewed. Results based on method compared to ones from designs, noticeable improvements demonstrate that scheme is an alternative way design. As in referenced...

The conductivity, current distribution, and radiation efficiency for a variety of dipole antennas constructed from carbon nanotube thread/rope are simulated using Hallén's integral equation thin wire applied to the method moments compared standard copper antenna. Next, conductivity weight fully fabricated thread rope samples measured analyzed. Finally, half-wavelength (CNT) antenna prototypes fabricated, measured, Simulation results indicate that CNT performance improves with increased...

A dual‐band element that operates with dual‐circular polarisation in two separate industrial, scientific and medical bands is presented. The design based on concentric square slot/shorted‐ring configuration realisable cost‐effective printed circuit board technology making it attractive for low‐cost personal communications devices. antenna provides a flexible topology allows convenient, independent control of the impedance bandwidth distinct frequency no fundamental limitation ratio between...

The evolution of satellite antennas over the past quarter a century is presented. Five major areas advances in communications antenna technology are reviewed: single offset reflectors with feed arrays, shaped reflector systems, active phased phased-array-fed dual and lightweight elements. Examples given existing systems ongoing development new technologies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Recent research on holographic and diffractive metasurfaces shows enormous promise for developing cheaper more compact systems. A metasurface aperture exploits the phase shift inherent in guided reference wave avoids using active elements such as phase-shifters associated with conventional phased arrays electronically scanned antennas. The radiation pattern can thus be controlled by altering properties of each element coupled to wave. In this paper, we discuss parameters control a radar or...

Index modulation (IM) is one of the candidate technologies for upcoming sixth generation (6G) wireless communications networks. In this paper, we propose a space-time-modulated reconfigurable intelligent metasurface (RI-MTS) that configured to implement various frequency-domain IM techniques in multiple-input multiple-output (MIMO) array configuration. Unlike prior works which mostly analyze signal theory general RI-MTS IM, present novel electromagnetics-compliant designs specific IMs such...