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This paper presents a low-profile multi-slotted patch antenna for long term evolution (LTE) and fifth-generation (5G) communication applications. The studied antenna comprised of a stepped patch and a ground plane. To attain the required operating band, three slots have been inserted within the patch. The insertion of the slots enhances the capacitive effect and helps the prototype antenna to achieve an operating band ranging from 3.15 to 5.55 GHz (S11 ≤−10 dB), covering the N77/N78/N79 for sub-6 GHz 5G wireless communications and LTE bands of 22/42/43/46. The wideband antenna presented in this paper offers omnidirectional stable radiation patterns, good gains, and efficiency with a compact size which make this design an ideal contender for wireless fidelity (WiFi), wireless local area network (WLAN), LTE, and sub-6 GHz 5G communication applications.
The subject here is the absorption coefficient, expressing the net power loss from the field over a unit path. At its heart is the line shape, which may be identified with the power spectral density function for fluctuations of the active dipole in the presence of an equilibrium bath of perturbers, and, as such, should satisfy the fluctuation–dissipation theorem. The more general properties of the absorption coefficient, which must reflect this balance, are first examined in some detail, particularly for the Van Vleck–Huber form. It is then shown that this, when expanded as a sum over individual lines, may be folded into more compact expressions. Outside the line core, these expressions must incorporate the fluctuation–dissipation theorem, and special attention is given to distinguish this case and that of the core itself, where it is of no consequence. Even the very general Fano theory does not, as it stands, satisfy the theorem, and can be used for the far-wing line shape only if these expressions are modified. Finally, some account is given of how they may be used with a molecular line database, and how a calculation of radiative transfer might proceed in the simplest of cases.
This chapter provides a practical discussion on the integration of UAVs into real-world cellular systems, ranging from long-term evolution (LTE) to 5G new radio (NR) and beyond. We first review the roles of mobile cellular technologies for UAV applications while highlighting the use of mobile connectivity and the role of mobile cellular technologies in enabling the development of new services for UAVs in key areas such as identification and registration, location-based services, and law enforcement. Then, we discuss LTE-enabled UAVs in more detail, including a tutorial on LTE and the various UAV use cases that include UAV LTE user equipment and UAV LTE base stations. We also touch upon some performance enhancing solutions that can optimize LTE connectivity for providing improved performance for UAVs while protecting the performance of terrestrial mobile devices. We then introduce various 3GPP standardization efforts on cellular-connected UAVs that aim to address the anticipated usage of mobile technologies by UAVs and regulatory requirements. Next, we discuss 5G NR-enabled UAVs while providing a primer on 5G NR essentials, how 5G NR can provide superior UAV connectivity, and the roles of network slicing and network intelligence for identifying, monitoring, and controlling UAVs in the 5G era.
In this manuscript, the time-resolved laser-induced breakdown spectroscopy (LIBS) on tungsten target in air and the coexistence of LTE among atoms and ions as well as the fulfillment of optically thin plasma condition are reported. The laser-induced plasma (LIP) of tungsten is generated by focusing the second harmonic of a Q-switched Nd:YAG laser of pulse width ~7 ns and repetition rate of 1 Hz on the tungsten target. The temporal evolution of LIP of tungsten is recorded at four different incident laser fluences of 60, 120, 180, and 270 J/cm2. The several atomic and singly ionized lines of tungsten are identified in LIP. For the estimation of plasma temperature via the Boltzmann plot, the transitions at 430.7, 449.4, 468.0, 484.3, 505.3, and 524.2 nm of Atomic transition of tungsten (WI) and that of the ionic transitions, First Ionic transition of Tungsten (WII) at 251.0, 272.9, and 357.2 nm are selected. The electron density is estimated using the Stark-broadened profile of WI line at 430.2 nm. The McWhirter criteria for the local thermodynamic equilibrium (LTE) condition is verified in present experimental conditions as well as the relaxation time and diffusion length are estimated to take into account the transient and inhomogeneous nature of the plasma. The optically thin plasma condition is studied by assessing the experimental intensity ratio of atomic lines and compared with that of the theoretical intensity ratio (branching ratio). The signal to noise ratio (SNR) is also obtained as a function of time with respect to laser pulse and incident laser fluence. All these observations indicate that the spectra should be recorded within the temporal window of 1–3.5 µs with respect to laser pulse where the plasma can be treated as optically thin as well as under LTE simultaneously along with the large SNR.
Cyclopropenylidene,, is a simple hydrocarbon, ubiquitous in astrophysical gases, and possessing a permanent electric dipole moment. Its readily observed multifrequency rotational transitions make it an excellent probe for the physics and history of interstellar matter. The collisional properties of with He are presented here. We computed the full Potential Energy Surfaces, and we perform quantum scattering in order to provide rates of quenching and excitation for low to medium temperature regimes. We discuss issues with the validity of the usual Local Thermodynamical Equilibrium assumption, and also the intricacies of the spectroscopy of an asymmetric top. We present the wide range of actual critical densities, as recently observed.
With the aim of performing perimeter surveillance of high-speed railway networks, this paper presents the design of a passive multistatic radar system based on the use of Long-Term Evolution (LTE) downlink signals as the illumination of opportunity. Taking into account the specifications and standard of the LTE system, the ambiguity function of measured downlink signals is analyzed in terms of range and Doppler resolution, ambiguities, and sidelobe level. The deployment of the proposed passive radar is flexible and scalable, and it is based on multichannel software defined radio receivers that obtain the reference and surveillance signals by means of digital beamforming. The signal processing and data fusion are based, respectively, on the delay-Doppler cross-correlation with the reconstructed reference signals and a two-stage tracking at sensor and central level. Finally, the performance of the proposed system is estimated in terms of its maximum detection range and simulation results of the detection of moving targets are presented, demonstrating its technical feasibility for the short-range detection of pedestrians, vehicles, and small drones.
Being connected “anywhere anytime” has become a way of life for much of the world's population. Thanks to major technological advances in internet, wireless communication, video technology, silicon manufacturing, etc., our mobile devices have become not only faster and more powerful, but also smaller and sleeker. With the popularity of rich media on the rise, the no. 1 data traffic over the mobile network is attributed to video. That is the reason why we depict the Freeman Dyson's book title “From Eros to Gaia.” Equipped with rich media capabilities, our mobile devices enable a completely different storytelling experience unlike anything the human race has experienced before. In this paper, we review the latest technological evolutions in the wireless space and in the video space, namely long-term evolution and high-efficiency video coding, respectively. We then discuss how these advanced technologies impact our way of life at present and in years to come.
In this paper, a novel design of compact wideband multiple-input multiple-output (MIMO) antenna operating over a frequency range of 1.8–4.0 GHz at 10 dB is presented for mobile terminals. The MIMO antenna design consists of two symmetrical and orthogonal radiating elements with a small size of 15.5 × 16.5 mm2 printed on the corners of a mobile circuit board. The radiating element is composed of four meandered monopole branches with a strip-line fed by a probe. By triangularly trimming the corners of the common ground plane beneath the radiating elements, not only the mutual coupling is reduced, but also impedance bandwidth is increased. Although, the antenna in this form has sufficient correlation level between the radiating elements for MIMO operation, a novel design of plus-shaped parasitic element is inserted to the ground plane between those radiating elements in order to further enhance the isolation. The performance of the MIMO antenna is investigated in terms of s-parameters, radiation pattern, gain, envelope correlation coefficient (ECC), and total active reflection coefficient (TARC), and is verified through the measurements. The results demonstrate that the proposed MIMO antenna has good characteristics of wideband, isolation, gain, radiation pattern, and is compatible with LTE, WiMAX, and WLAN, besides it is small, compact, and embeddable in mobile terminals.
Stress questionnaires are included in many epidemiological cohort studies but the psychometric characteristics of these questionnaires are largely unknown. The aim of this study was to describe these characteristics for two short questionnaires measuring the lifetime and past year occurrence of stress: the List of Threatening Events (LTE) as a measure of acute stress and the Long-term Difficulties Inventory (LDI) as a measure of chronic stress.
This study was performed in a general population cohort consisting of 588 females (53.7%) and 506 males (46.3%), with a mean age of 53.5 years (s.d.=11.3 years). Respondents completed the LTE and the LDI for the past year, and for the age categories of 0–12, 13–18, 19–39, 40–60, and >60 years. They also completed questionnaires on perceived stress, psychological distress (the General Health Questionnaire, GHQ-12), anxiety and depression (the Symptom Checklist, SCL-8) and neuroticism (the Eysenck Personality Questionnaire – Revised Short Scale, EPQ-RSS-N). Approximately 2 years later, 976 respondents (89%) completed these questionnaires for a second time.
The stability of the retrospective reporting of long-term difficulties and life events was satisfactory: 0.7 for the lifetime LDI and 0.6 for the lifetime LTE scores. The construct validity of these lists is indicated by their positive associations with psychological distress, mental health problems and neuroticism.
This study in a large population-based sample shows that the LDI and LTE have sufficient validity and stability to include them in major epidemiological cohort studies.
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