Monopole Structure Research Articles

The comparison study of the monopole tower foundation using CPT and laboratory data in Gresik district, East Java-Indonesia

In the millennial era, the development of information and communication technology is very fast, one of the telecommunications infrastructure is a monopole type telecommunications tower. This type of tower is one of 3 types of telecommunication towers whose main construction is made of steel. The monopole structure is supported by a tread foundation, which is one type of shallow foundation. The main factor in the design of the tread foundation is the bearing capacity factor. Calculation of foundation bearing capacity can be done directly in the field using Sondir data (CPT) and indirectly using laboratory data. In this study a study was conducted to compare the carrying capacity of monopole foundations between field data methods in the form of Sondir data or CPT with result data. Soil tests in the laboratory calculated with the Terzaghi formula. The research location was carried out in Gresik Regency, East Java Province, Indonesia at 3 sites, namely: Mojosarirejo, Kembangan Kebomas and Setromenganti. The results of the comparison of the calculation of the bearing capacity of the foundation (Q) at the Mojosarirejo site with the type of sandy soil. value of QSondir < 9.58 % of Qterzaghi. At the Krembangan Kebomas site with brown clay and gravely clay, the Q value was < 69.93 % of the Qterzaghi and at the Setromenganti site with brown clay soil type with the influence of water level depth – 1 m, the Q value was < 27, 62% of Qterzaghi. From the comparison of the average calculation in the 3 study locations, the bearing capacity of QSondir treads foundation is 26.50 % smaller than Qterzaghi, so the use of Sondir data is more accurate for use in tread foundation planning and provides greater security assurance for the tower foundation structure. monopole type

Linkages of surface air temperature variations over Central Asia with large-scale climate patterns

In this study, we investigate the dominant modes of surface air temperature variations of the cold season (from November through to the next March) and the warm season (from May to September) over Central Asia, and their associations with large-scale climate patterns for the period of 1979–2016. The first two modes of the cold season surface air temperature (CSAT) over Central Asia, obtained by empirical orthogonal function (EOF) analysis, feature the monopole structure and the north-south dipole pattern, respectively. For the warm season surface air temperature (WSAT), the leading two EOF modes are characterized by the homogenous structure and the northwest-southeast seesaw pattern, respectively. Further analysis indicates that the large-scale atmospheric circulation anomalies play key roles in the CSAT and WSAT variations over Central Asia. The CSAT variation over Central Asia is closely related to the Scandinavia pattern (SCAND) and the Arctic Oscillation (AO), while the WSAT variation is tightly tied to the East Atlantic/Western Russia pattern (EAWR) and the North Atlantic Oscillation (NAO). These large-scale climate patterns tend to cause the CSAT and WSAT anomalies over Central Asia via their effects on regional geopotential heights, warming advections, and other processes. Positive geopotential height anomalies and increased downward solar radiations generally favor positive SAT anomalies over Central Asia. Moreover, the warm advections are also conducive to the formation of positive SAT anomalies over Central Asia. Our findings are expected to facilitate the improvement of understanding and predicting the CSAT and WSAT variations over Central Asia.

An Analysis of RF On-Chip Antennas in Si-Based Integrated Microwave Photonics

We investigate the monolithic integration of RF antennas onto a silicon-based integrated microwave photonics (IMWP) chip for short-range millimeter-wave (mmW) communication. The unification of antenna with photonic integrated circuits (PICs) reduces system loss for high data rate communication by eliminating parasitic interconnects. This integration of electronics (antenna) with photonics will be a key milestone leading to increased bandwidth capability and ubiquitous wireless links for emerging applications such as 5G, Internet of Things (IoT), autonomous vehicles, high data rate point-to-point communication, and wireless sensors. Through simulation above 20 GHz, we compare the transmission of three on-chip antenna structures designed in a commercial silicon photonics (SiPh) process and consider them for both inter and intra-chip communication. Results provide insight on the transmission gain variations relative to the antenna orientation from their distinct radiation pattern. The folded monopole structure provides superior gain, smaller footprint with layout flexibility, and good transmission spectrum. The analysis supports the idea of a monolithic mmW transmitter integrated with on-chip antennas on IMWP chip.

Drivers of Eurasian Spring Snow-Cover Variability

AbstractThe variability of spring snow cover over Eurasia can have notable impacts on the current and following season climate, but the causes of it are poorly understood. This study investigates the potential drivers and the associated physical processes for the first two empirical orthogonal function (EOF) modes of the Eurasian spring snow-cover variability during 1967–2018, which are characterized by a continent-wide coherent pattern and a west–east dipole structure, respectively. Analyses show that the spring surface air temperature and snowfall are the direct factors influencing the two modes. We further examined the contributions to the snow-cover variability of atmospheric teleconnection patterns, sea surface temperature (SST) anomalies, and variations of Arctic sea ice during spring. The results indicate that circulation anomalies associated with the Arctic Oscillation, Polar–Eurasian pattern, and West Pacific pattern can partly explain the formation of the EOF1 mode, while the EOF2 mode has a close relationship with the East Atlantic–Western Russia pattern. In addition, a horseshoe-like monopole structure of SST anomalies over the North Atlantic plays an important role in regulating the EOF2 mode by inducing a wave train circulation. Moreover, the EOF2 mode is also affected by anomalous circulations induced by the sea ice anomalies in the Barents–Kara Seas. An empirical model using these drivers satisfactorily reproduced the temporal variations of the two EOF modes, implying that our results can substantially improve comprehension of the variability of Eurasian spring snow cover.

Compact hexa-band bio-inspired antenna using asymmetric microstrip feeding technique for wireless applications

A compact Hexa-band Bio-inspired antenna is presented in this paper. The structure of the proposed antenna is realized from a semi-Vine-leaf shape, Defected Ground Structure (DGS) and arc-slots techniques. The total dimension of the antenna is 0.35λd x 0.14λd; where λd is the guided wavelength at low frequency (2.37GHz). The design begins with a semi-Vitis vinifera leaf-shaped radiating patch monopole structure, fed with an asymmetric microstrip feedline to achieve compactness. Five (5) arc slits are then introduced on the radiating patch of the initiator with an intention to create band notches and thereby results in multiband and further miniaturization. The proposed antenna is analyzed, simulated and fabricated. The measurement results of the proposed antenna show that the antenna operates at 2.37GHz, 3.06GHz, 3.52GHz, 4.28GHz, 4.88GHz, and 6.0GHz with a -10dB fractional bandwidth of 11.97%, 4.61%, 12.43%, 6.77%, 2.46%, and 11.55% respectively. The peak gain of the proposed antenna is 3.21 dBi. The radiation patterns of the proposed antenna are Bi-directional at XZ-plane and XY-plane, but Omnidirectional at YZ-plane. Owing to the compactness of the antenna, suitable radiation pattern, acceptable gain and high radiation efficiency, the proposed antenna is suitable for several applications such as Industrial, Scientific and Medical (ISM) Band, Radar, WiMAX, 5G mid-band, Bluetooth, WLAN, WiMAX, LTE, and Wi-Fi. The contributions of this work are: (i) the use of asymmetric microstrip feedline for miniaturization purpose contrary to the commonly used asymmetric coplanar strip; (ii) simple formulation for the predictions of notch bands introduced by the slit on the radiating patch; and (iii) presentation of ultra-compact hexa-band antenna compared to the existing multiband antenna.

The geometry of mesoscale eddies in the South China Sea: characteristics and implications

ABSTRACT The symmetrical circular shape of mesoscale eddies has been widely used in their scientific researches. Recently, an elliptical average eddy shape has been confirmed for eddies in the global ocean using multi-satellite altimeter data. As a regional extension of a previous study on the geometry of global eddies, a mean eddy shape in the South China Sea (SCS) has been derived by averaging a large number of orientational eddy boundaries. The mean shape is approximately a mathematic ellipse with a semimajor axis of 101.3 km and a semiminor axis of 61.3 km. Its size is larger than the global one. The principal eddy orientation in the SCS is 74°/254° (nearly northeast-southwest), different from that of eddies in the global ocean (171°/351°, nearly east–west). Composite analyses of chlorophyll (CHL) concentrations and sea surface temperature anomalies (SSTA) indicate a dipole structure for circular eddies in the non-rotated coordinate system. While a monopole structure for elliptical eddies in the eddy-centric coordinate system is obtained. The results demonstrate that the elliptical shape of eddies affects oceanographical variables. The findings provide a new approach for exploring the role of air–sea interactions on oceanic eddies.

Design of 5g Mimo Antenna with Enhanced Isolation

In this paper, MIMO 2-port, 2-element antenna for 5G applications is presented. This is monopole antenna structure consists of two-rectangular patch of same shapes. Each antenna has a feeding plate connect at the centre of the patch antenna for enhancing isolation the etching of rectangular slots on the ground plane in between the two patches along with thick and sheet of the substrate just below at the centre of the patch. Maximum isolation achieved among the ports is less than -30db. envelope correlation coefficient is below 0.10 in bands of interest. The minimum frequency range covered by the four ports of this antenna is from around 3.0 to 4.0 GHz, thus covering expected future 5G band (3300–3700 MHz).

Modified wideband monopole antenna for unmanned aerial vehicle communication

AbstractIn this article, a novel surface‐mounted type wideband monopole antenna for VHF band unmanned aerial vehicle (UAV) communication is presented. The proposed antenna constitutes a planar monopole structure such that taper‐feeding configuration is adopted for wideband impedance matching and the radiation element of the antenna is formed on the vertical and horizontal parts of the narrow tail wing of the UAV to obtain monopole‐like radiation pattern. After designing the antenna, simulation was performed in the VHF band of 0.11‐0.17 GHz and the results showed the characteristics of the monopole. Because the antenna size of VHF band is too large to be tested, after 1/7 size scaling, the simulation and the measurement were performed in the frequency band of seven times the original band. The results show that the 10 dB return‐loss band is 0.732‐1.242 GHz (52.0%), the average gain in the H‐plane is −0.23 dBi, and the radiation patterns are very similar to those of the monopole antenna.

Cosmic anisotropy and fast radio bursts

In the recent years, the field of fast radio bursts (FRBs) is thriving and growing rapidly. It is of interest to study cosmology by using FRBs with known redshifts. In the present work, we try to test the possible cosmic anisotropy with the simulated FRBs. In particular, we only consider the possible dipole in FRBs, rather than the cosmic anisotropy in general, while the analysis is only concerned with finding the rough number of necessary data points to distinguish a dipole from a monopole structure through simulations. Noting that there is no a large sample of actual data of FRBs with known redshifts by now, simulations are necessary to this end. We find that at least 2800, 190, 100 FRBs are competent to find the cosmic dipole with amplitude 0.01, 0.03, 0.05, respectively. Unfortunately, even 10 000 FRBs are not competent to find the tiny cosmic dipole with amplitude of . On the other hand, at least 20 FRBs with known redshifts are competent to find the cosmic dipole with amplitude 0.1. We expect that such a big cosmic dipole could be ruled out by using only a few tens of FRBs with known redshifts in the near future.

Spontaneous formation of geysers at only one pole on Enceladus’s ice shell

The ice shell on Enceladus, an icy moon of Saturn, exhibits strong asymmetry between the northern and southern hemispheres, with all known geysers concentrated over the south pole, even though the expected pattern of tidal forced deformation should be symmetric between the north and south poles. Using an idealized ice-evolution model, we demonstrate that this asymmetry may form spontaneously, without any noticeable a priori asymmetry (such as a giant impact or a monopole structure of geological activity), in contrast to previous studies. Infinitesimal asymmetry in the ice shell thickness due to random perturbations are found to be able to grow indefinitely, ending up significantly thinning the ice shell at one of the poles, thereby allowing fracture formation there. Necessary conditions to trigger this hemispheric symmetry-breaking mechanism are found analytically. A rule of thumb we find is that, for Galilean and Saturnian icy moons, the ice shell can undergo hemispheric symmetry breaking only if the mean shell thickness is around 10 to 30 km.

Ultrawideband Textile Antenna for Wearable Microwave Medical Imaging Applications

This article presents the design of a novel low-profile ultrawideband textile antenna for wearable microwave medical imaging systems. The proposed antenna is based on a monopole structure, where two triangles and a few parallel slots are cut at the bottom corners and top edge of the radiation patch, respectively, to achieve an optimized ultrawide bandwidth and a reduced size of the antenna. Polyester fabrics and conductive copper taffeta, which are universally available on the market, are selected to construct the antenna. Thus, the fabricated prototypes well suit the needs of wearable applications, where flexible components are required to conform to the curved human bodies. The measured results show that the antenna prototype can realize a bandwidth of 109% from 1.198 to 4.055 GHz, with a realized gain of 2.9 dBi. Furthermore, the on-phantom measurements show that there is limited effect on the operating bandwidth and realized gain of the antenna when it is working in the proximity to human bodies. The antenna is used to monitor the recovery process of a bone fracture that is emulated by a body-mimicking phantom with a size-varying blood strip. The time-domain reflection coefficient of the antenna varies significantly with the size of the fracture introduced, which demonstrates the applicability of the antenna for such use scenarios in microwave medical imaging.

A Tripolarized Antenna With Ultrawide Operational Bandwidth

In multiscattering environment, the channel capacity can be enhanced by employing dual-polarized antennas, and more significantly, using tripolarized antennas. Aiming at providing a wide coverage of both existing wireless communication systems and the new 5G sub-6 GHz band, this article presents a compact ultrawideband tripolarized antenna. The proposed design consists of a monopole-equivalent structure for vertically linearly polarized (LP) omnidirectional radiation and two orthogonal stepped dipoles for ±45° LP broadside radiation. Several important design features are proposed and implemented. The dipoles act as parasitic elements for the monopole structure, which broadens the monopole bandwidth and reduces the mutual coupling. Furthermore, the port isolation is improved by inserting two metallic posts between the crossed dipoles and the ground plane. The measured results indicate that the fabricated prototype achieves an overlapped bandwidth of 84.73% (1.68–4.15 GHz) for <−10 dB reflection coefficient and coupling value of <−30 dB among all ports. Tripolarized radiation is verified with pattern measurement, showing peak realized gains of 8.4 and 9.4 dBi in monopole and two broadside modes, respectively.

The influence of nonlinearities and different SST spatial patterns on the summertime anomalies in subtropical South America during strong ENSO events

In this study we analyze the impacts of the strongest ENSO events on subtropical South America (SSA) rainfall during the austral summer in the period (1979–2014). We consider reanalysis data and model experiments. For the strongest El Nino events, the precipitation pattern over SSA presents a monopole structure. The reanalysis shows a short Rossby wave train that causes an increase of the baroclinicity and advection of cyclonic vorticity toward SSA. Together with an increase in the moisture transport by the South American Low Level jet (SALLJ), they induce strong positive precipitation anomalies over SSA. The model reproduces this rainfall anomaly as consequence of a strengthening of the upper level jet and of the SALLJ, although it does not simulate the short wave train from the Pacific. For the strongest La Nina events, the precipitation pattern presents a tripole like-structure with centers located over: (1) Uruguay, (2) the continental part of the South Atlantic Convergence Zone (C-SACZ) and (3) the northwestern Argentina (NW-Arg). In both cases, reanalysis and model experiments, the tripole is associated with a weakening of the SALLJ that increases (reduces) rainfall anomalies over C-SACZ (Uruguay), and with an anomalous increase of the lower level moisture convergence over NW-Arg that increases precipitation over there. Differences in precipitation responses to the strongest ENSO events are mainly associated to changes in the spatial pattern of the sea surface temperature anomalies, however, there is also a contribution of nonlinearities.

Near-Surface Ozone Variations in East Asia during Boreal Summer

This study examined the variability of near-surface (850 hPa) ozone during summer in East Asia using simulations from 12 models participating in the Chemistry–Climate Model Initiative (CCMI). The empirical orthogonal function (EOF) analysis of non-detrended ozone shows that the first (second) EOF mode is characterized by a monopole (dipole) structure that describe 83.3% (7.1%) of total variance. The corresponding the first principle component (PC1) time series exhibits a gradually increasing trend due to the rising anthropogenic emission, whereas PC2 shows interannual variation. To understand the drivers of this interannual variability, the detrended ozone is also analyzed. The two leading EOF patterns of detrended ozone, EOF1 and EOF2, explain 37.0% and 29.2% of the total variance, respectively. The regression results indicate that the positive ozone anomaly in East Asia associated with EOF1 is caused by the combination of net ozone production and transport from the upper atmosphere. In contrast, EOF2 is associated with the weakened western Pacific subtropical high during the La Niña decaying summer, which tends to decrease monsoon precipitation, thus increasing ozone concentration in China. Our results suggest that the El Niño-Southern Oscillation (ENSO) plays a key role in driving interannual variability in tropospheric ozone in East Asia.

Characteristics and vertical structure of oceanic mesoscale eddies in the Bay of Bengal

The signatures of mesoscale eddies induced surface and subsurface changes have not been comprehensively quantified for the Bay of Bengal (BoB) region. This study quantifies the statistical properties and three-dimensional (3D) eddy structures in the BoB. To accomplish this, the satellite altimetry data combined with automated eddy detection and tracking algorithm is used. Horizontal distribution of surface characteristics of eddies is analyzed by using 24 years (1993–2016) of AVHRR infrared satellite sea surface temperature (SST) and 7 years (2010–2016) of sea surface salinity (SSS) of SMOS satellite data. Surface eddy centric composite analysis reveals the existence of warm (cold) and diverse SSS anomalies for anticyclonic (cyclonic) eddies. During winter, it is important to note that the eddy induced SST and SSS anomalies show the dipole patterns show opposite phases for the cyclonic and anticyclonic eddies. Observed diploe structures are consistent with the eddy rotation and background large-scale meridional gradient of temperature and salinity fields. The 3D structure of eddies is investigated by using the ARMOR3D and Argo float profiles. The horizontal distribution of temperature and salinity anomalies from ARMOR3D signify the monopole structure of eddies in the subsurface layers. Further, the analysis of composite averages of 241 (200) Argo temperature profiles indicates the core of anticyclonic (cyclonic) eddies centered at about ∼140 m (∼100 m). However, salinity profiles depict the existence of core at ∼65 m (∼50 m). This study have practical relevance to a variety of stakeholders and finds profound importance in the validation of eddy-resolving ocean models for the BoB region.

Dual‐band dual‐polarized compact planar monopole antenna for wide axial ratio bandwidth application

In this article, a geometrically simple, microstrip line-fed planar monopole structure with slanting edge ground plane is designed to realize the dual-band dual-polarized operation. The proposed antenna consists of a rotated U-shaped patch and an electromagnetically coupled L-shaped parasitic radiating element. Owing to the combination of microstrip line-fed radiating patch and a slanting-edge rectangular ground plane on the opposite side of the substrate, the proposed dual-band antenna can generate broad axial ratio bandwidth (ARBW) in the upper frequency band. The overall dimension of the prototype is only 32 × 32 × 1.6 mm3. The measured results validate that the proposed antenna has two operational frequency bands, 29.84% (1.54-2.08 GHz) for linearly polarized radiation and 71.85% (3.96-8.4 GHz) for circularly polarized radiation. Measured result shows that 3-dB ARBW of the proposed antenna is 73.54% (3.80-8.22 GHz) in the higher frequency band. It shows that the higher frequency band exhibits a left-hand circularly polarized radiation in the boresight direction.

Thermohaline Structures and Heat/Freshwater Transports of Mesoscale Eddies in the Bay of Bengal Observed by Argo and Satellite Data

Knowledge of mesoscale eddies in the Bay of Bengal (BOB) is key for further understanding the climate variability in this region and beyond, but little is known about the vertical structure of these eddies. In this study, the three−dimensional structure and transport characteristics of mesoscale eddies in the BOB were comprehensively investigated by the combined use of Argo profiles and satellite data. The composite analysis showed that eddy−induced ocean anomalies are mainly confined to the upper 300 m of the water. The spatial structure of eddy−induced thermohaline perturbations is characterized by a dominant dipole structure in the near surface layer, arising from horizontal advection of the background thermohaline gradient by eddy rotation, and a monopole structure in the subsurface layer, caused by eddy−induced vertical displacements of the isopycnal surfaces. In the eddy core, the maximum temperature anomalies induced by a cyclonic eddy (CE) and an anticyclonic eddy (AE) are about −1.2 °C and +1.2 °C, respectively. The anomalies are located at approximately 100 m. The corresponding salinity anomalies are located at approximately 50 m with a value of −0.1 psu (0.1 psu) for CE (AE). The eddy thermohaline structure has a seasonal character. A deeper temperature and salinity core occurs in both CE and AE in spring compared to that in other seasons, which is primarily caused by the relatively deep thermocline and halocline during that season. In addition, unique warming anomalies induced by CE are present in the mixed layer during winter due to the vertical advection of the BL (Barrier Layer) warmer water by eddies. The total meridional heat transport induced by the composite eddy is poleward (equatorward) south (north) to 10°N with a value of 0.01 PW (−0.013 PW), whereas the total meridional freshwater transport is equatorward with a value of 0.046 Sv over a one−year period. The volume of freshwater export out of the bay is approximately 35% of the annual net freshwater input from local precipitation and river discharge.

Wideband MIMO Antenna Array Design for Future Mobile Devices Operating in the 5G NR Frequency Bands n77/n78/n79 and LTE Band 46

An eight-antenna array with wideband operation for future 5G New Radio mobile devices is studied. Each array element is composed of an inverted-F antenna with shorting branches and parasitic elements. The driving element (monopole structure) and the shorting element (inverted-L branch and inverted-C branch) enable the antenna to obtain multiple modes, whereas the parasitic element, open slit, and stub can improve the impedance matching. The 6 dB impedance bandwidth of the proposed eight-antenna array can completely cover the 5G Sub-6 GHz NR frequency Bands n77/n78/n79, which include the 5G band of U.S. (3.55–4.2 GHz), China, EU, and Japan (3.6–4.2 GHz and 4.4–4.9 GHz), as well as the LTE Band 46 (5.15–5.925 GHz). From the measured results, the isolation between adjacent array elements is lower than 10 dB and its corresponding envelope correlation coefficient is also lower than 0.1.

Complete description of the magnetic ground state in spinel vanadates

Capturing the non-collinear magnetic ground state of the spinel vanadates AV$_2$O$_4$ (A= Mn, Fe and Co) remains an outstanding challenge for state-of-the-art ab-initio methods. We demonstrate that both the non-collinear spin texture, as well as the magnitude of local moments, are captured by a single value of the on-site Hubbard $U$ of 2.7~eV in conjunction with the local spin density approximation (LSDA+$U$), provided the source term (i.e., magnetic monopole term) is removed from the exchange-correlation magnetic field ${\bf B}_{XC}$. We further demonstrate that the magnetic monopole structure in ${\bf B}_{XC}$ is highly sensitive to the value of $U$, to the extent that the interplay between on-site localization and local moment magnitude is qualitatively different depending on whether the source term is removed or not. This suggests that in treating strongly correlated magnetic materials within the LSDA+$U$ formalism, subtraction of the unphysical magnetic monopole term from the exchange-correlation magnetic field is essential to correctly treat the magnetic ground state.

Internal fork‐shaped wideband monopole antenna with a parasitic sleeve for ultra‐high‐definition television applications

AbstractA simple and compact internal fork‐shaped monopole antenna with a parasitic sleeve is proposed for operation in the ultra‐high frequency (UHF: 470‐771 MHz) band for ultra‐high‐definition television (UHD‐TV) applications. The internal antenna is directly implemented into a 49‐in TV model on which its bezel frame (made of PC‐ABS with εr = 3.5 and tanδ = 0.005) is used as a substrate for antenna design. The structure and operation bandwidth of the internal antenna are restricted by the limited space and longitudinal bezel frame. Therefore, the fork‐shaped monopole structure with meandering and folding strips is applied, forming a capacitive coupling effect to reduce the antenna size and to enhance the impedance matching. A parasitic sleeve is added and encircled around the monopole to generate additional resonances, hence further broadening the operating bandwidth to cover the entire UHF band. The antenna is then bent to form a three‐dimensional structure with a compact dimension of 275 × 17 × 5 mm3, allowing it to be tightly fitted on the bezel frame of the TV model. The final tested antenna achieves a peak gain of 4.7 dBi and an efficiency of more than 60% over a broad −6 dB reflection bandwidth of 60.3% (440‐820 MHz).