Orthogonal Lines Research Articles

The Kolam Drawing: A Point Lattice System

Abstract Kolam is the 5,000-year-old art of making geometric floor drawings with rice flour, practiced by the Dravidian women of South India. This article introduces a point lattice-based method of visual organization that is derived from Kolam drawings. In it, a point lattice formed by a regularly spaced array of points is used to structure visual compositions, as an alternative to a network of orthogonal lines (also known as the grid). First, I show how the point lattice system is used to structure Kolam drawing compositions, including the lattice's construction, types, and uses. Second, through a formal analysis of such a points system in structuring forms, patterns, letters, and layouts in graphic design, I show that this system offers a whole alternate universe of compositional possibilities that are not apparent when graphic designers see a grid not as points, but as a series of constraining straight lines. Through this research, I look inward into the design ethos and tools present in Indian arts and crafts and present its application in contemporary design practice.

A Compact Dual-Band Self-Diplexing MIMO Patch Antenna for ISM and X-Band Communications

A compact, dual-band, and self-diplexing MIMO patch antenna with a shared aperture is presented for Industrial scientific medical (ISM) band and X-band communications. The structure consists of two orthogonal feed lines and a rectangular slot in a square patch. The size of the FR4 substrate is 50 × 50 × 1.6 mm3. The designed structure operates at 5.8 (ISM) and 8 GHz (X-band) frequencies independently with a simulated peak gain of 5.46 and 3.59 dBi respectively. A 13 dB of isolation is obtained for the two orthogonal ports. The obtained frequency ratio range is 1.20-1.33 over the reflection bandwidth. The design structure is fabricated and validated experimentally. The compactness and promising performance in terms of low ECC (Envelope Correlation Coefficient) (<0.1), high peak gain can make the proposed antenna a choice for current wireless devices.

Evaluation of the global-blockage effect on power performance through simulations and measurements

Abstract. Blockage effects due to the interaction of five wind turbines in a row are investigated through both Reynolds-averaged Navier–Stokes simulations and site measurements. Since power performance tests are often carried out at sites consisting of several turbines in a row, the objective of this study is to evaluate whether the power performance of the five turbines differs from that of an isolated turbine. A number of simulations are performed, in which we vary the turbine inter-spacing (1.8, 2 and 3 rotor diameters) and the inflow angle between the incoming wind and the orthogonal line to the row (from 0 to 45∘). Different values of the free-stream velocity are considered to cover a broad wind speed range of the power curve. Numerical results show consistent power deviations for all five turbines when compared to the isolated case. The amplitude of these deviations depends on the location of the turbine within the row, the inflow angle, the inter-spacing and the power curve region of operation. We show that the power variations do not cancel out when averaging over a large inflow sector (from −45 to +45∘) and find an increase in the power output of up to +1 % when compared to the isolated case under idealised conditions (neutral atmospheric conditions, no vertical wind shear or ground effects). We simulate power performance “measurements” with both a virtual mast and nacelle-mounted lidar and find a combination of power output increase and upstream velocity reduction, which causes an increase of +4 % in the power coefficient under idealised conditions. We also use measurements from a real site consisting of a row of five wind turbines to validate the numerical results. From the analysis of the measurements, we also show that the power performance is impacted by the neighbouring turbines. Compared to when the inflow is perpendicular to the row, the power output varies by +1.8 % and −1.8 % when the turbine is the most downwind and upwind of the line, respectively.

A low profile single feed compact dual-band penta-polarization agile microstrip antenna for interference mitigation in point to point link in Ultra-Dense environment

This study takes an antenna perspective approach to mitigate signal interference issues in ultra-dense environment along with communication and signal processing domain. A compact single layered dual-band penta-polarization agile microstrip patch antenna (MSA) using single feed is studied and proposed. Each band switches between five distinct polarization states. Additionally, the proposed antenna possesses a very low profile of less than 0.01λ (λ free-space wavelength). A square patch is enclosed by a square ring to attain two distinct reconfigurable frequency bands by using switching diodes and biasing networks. Orthogonal microstrip lines connected with a single coax feed are selectively chosen by biasing network to excite the adjacent patch edges to achieve dual linear polarization (LP). Circular polarization (CP) with dual sense of rotation at each band is attained by switchable diagonal-truncated corners of outer ring. Subsequently, 45° slant polarization is achieved by simultaneous activation of the orthogonal feed lines with equal phases and amplitude. A penta-polarized antenna prototype is designed and fabricated to operate at 5.2 GHz and 5.8 GHz bands respectively. Simulation results of all ten reconfigurable states are found to be consistent with the measurement.

A shielded QMSIW ultra-compact self-diplexing antenna for WiMAX/WLAN applications

In this contribution, novel design is presented for a very compact shielded quarter-mode substrate-integrated waveguide (S-QMSIW) based self-diplexing antenna (SDA) for WiMAX/WLAN applications. In order to achieve dual-band features, a slot is etched onto the top of the metal. Two orthogonal microstrip feed lines in the full-wave EM-simulator (HFSS) simulate the S-QMSIW resonator at two different frequencies (3.45 and 5.45 GHz). The proposed antenna pattern is extremely adaptable, allowing for simple frequency adjustments for each resonant frequency. A lumped circuit model is expected to be used to assess the antenna structure. A self-diplexing antenna based on S-QMSIW was designed, fabricated and tested to claim the proposed concept. At 3.45 and 5.45 GHz, the proposed antenna peak gains are 4.7 and 5.6 dBi, respectively. It offered port isolation better than 38 dB. The antenna front-to-back ratio was greater than 19.5 dB in each band. The proposed antenna circuit size was very compact ().

SPLP: A Certifiably Globally Optimal Solution to the Relative Pose Estimation Problem Using Points and Line Pairs

Estimating the relative pose between two calibrated views with 2D-to-2D correspondences is a fundamental problem in computer vision and 2D perception. In this paper, we present the first certifiably globally optimal solver that can simultaneously incorporate both points and lines as the non-minimal 2D-to-2D correspondences for this problem. Our first contribution is to derive a generalized polynomial-based objective function based on the geometric constraints of orthogonal and parallel line pairs. Built upon it, our second contribution is to reformulate the relative pose estimation problem as a constrained global optimization problem with a unified representation of both point and line pair correspondences. Our third contribution lies in relaxing this non-convex optimization problem to a convex Semi-Definite Program (SDP) using Sum of Squares (SOS) relaxations so as to solve it via Gloptipoly 3 with a reliable guarantee of global optimality. In both synthetic and real experiments, we show that adopting line pairs as supplementary correspondences can greatly improve estimation accuracy, especially in the point-sparse situations, and that our solver, named SPLP (SOS-Point-and-Line-Pair), can outperform other state-of-the-art solvers.

The Reliability of CT Scan Measurements of Pelvic Incidence in the Evaluation of Adult Spondylolisthesis.

Background: Pelvic incidence (PI) has been described as a parameter that may be a risk factor for lumbar spondylolisthesis (SPL). Studies have reported PI measurement is more precise in CT scans. Very limited studies have measured PI using CT scans to evaluate SPL. We analyzed the reliability of CT scans to measure PI to evaluate SPL and compared it to patients without SPL.Methods: A retrospective, cross-sectional study of PI in a consecutive cohort of patients’ pelvic/abdominal CT scans from an emergency room visit at a Level 1 trauma center between 2013 and 2016. Inclusion criteria was >18 years and had no lumbar or pelvis fracture. A total of 361 patients met the criteria for our study. We documented age, average PI, and SPL (type, grading, and location). Sagittal CT scans were used to measure PI (between hip axis to an orthogonal line originating at the center of superior end plate axis of first sacral vertebra). Patients were categorized: with SPL (n=45) and without SPL (n=316). Subgroups were comprised based on the location of SPL (L4/L5 and L5/S1) and type of SPL. Analysis of variance (ANOVA) and chi-square tests used; p≤0.05 considered statistically significant.Results: Patients with SPL were significantly older versus patients without SPL, p=0.006. There were no statistical differences in PI between patients with and without SPL (p=0.29); between subgroups of patients with SPL at L4/L5 and without SPL (p=0.52); between subgroups with type of SPL at L4/L5 and without SPL (p=0.47); and between SPL patients at L5/S1 and without SPL (p=0.40). Patients with isthmic SPL at L5/S1 had nearly significant higher PIs (p=0.06) compared to those without SPL or with degenerative SPL at L5/S1. There was a trend towards higher PI in Grade 2 SPL patients at L5/S1, p=0.18.Conclusions: Patients with SPL were significantly older than patients without SPL. The two trends observed were that PI was higher in patients with isthmic SPL at L5/S1 and an increased PI with Grade 2 isthmic SPL at L5/S1. Our reported CT PI measurements correlated with reported PI measured using standard radiographs in patients with SPL. CT scans may be a reliable modality to evaluate adult SPL.

Highly-Miniaturized Dual-Mode Bandpass Filter Based on Quarter-Mode Substrate Integrated Waveguide With Wide Stopband

This paper presents a novel design of a highly-miniaturized dual-mode bandpass filter (BPF) employing a quarter-mode substrate integrated waveguide (QMSIW). The QMSIW resonator is based on a square cavity with metallic vias along two sides, and open-ended edges at the remaining sides that contain orthogonal feed lines. An open slot is introduced along the two sides of the square cavity with metallic vias to form a magnetic wall. A single metallic via is assigned at the corner of the two open-edged sides to form an electrical wall, which produces different resonances. By loading a slot diagonally, the mode frequencies can be controlled independently, which allows us to realize a second-order BPF. The detailed design steps and a flowchart explaining the filter’s topology evolution are presented. The eigen-mode analysis, field distributions, coupling matrix, and full-wave simulation of the proposed QMSIW filter topology are used to determine the filter’s operating principle. To verify the proposed theory, a second-order BPF is realized, fabricated, and demonstrated experimentally. The BPF prototype exhibits excellent performance such as a small footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.019\lambda ^{2}$ </tex-math></inline-formula> , a wide passband of 34.8-percent, low insertion loss of 0.43 dB, and a wide stopband of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.36f_{0}$ </tex-math></inline-formula> with a rejection level greater than 20 dB. Excellent consistency is found between the EM-simulated and measured responses of the device.

The Effects of Stress Triaxiality on the Neck Initiation and Fracture of High-density Polyethylene (HDPE)

This study analyses the tensile mechanical behaviour and deformation of neck i.e localization initiation, propagation and fracture of injection-moulded polymer composed of high-density polyethylene (HDPE) as a function of initial stress triaxiality. Three different specimen geometries namely i) Simple tension, ii) Plane strain and iii) Shear specimens were punched from injection-moulded HDPE plates and tested experimentally in uniaxial tension to introduce different stress triaxialities. These specimen geometries used are standard for the material characterization of sheet metals. However, for plate polymer materials such specimen geometries have not comprehensively been studied earlier. Standard shear specimen geometry has been further optimized in this work using finite element models to restrict unwanted out-of-plane deformations arising at large deformation. The digital image correlation (DIC) technique is used to acquire the full field deformation and in particular the localized strains in the neck region of the specimens. Based on the major-minor strain paths from DIC-measurements stress triaxiality has been calculated. It is challenging to follow the stochastic pattern at larger local strain in DIC and hence the strain at failure has been measured using orthogonal grid lines on the specimen surface. Finally, strains at neck-initiation and failure at three different stress triaxialities are reported for injection-moulded HDPE in two material orientations. It is observed that within the elastic limit the stress triaxialities obtained from the experimental tests were close to the ideal values found in the literature and neck-initiation strain is strongly dependent on the stress triaxiality. However, as neck initiates and propagates, the triaxialities for all geometries shift closer to the measured value in a simple tension specimen i.e. 0.33 limiting the effect of the initial triaxiality on failure strain.

Compact dual-mode microstrip bandpass filter based on slotted square patch resonator

PurposeThe purpose of this paper is to present the design of a compact microstrip bandpass filter (BPF) in dual-mode configuration loaded with cross-loop and square ring slots on a square patch resonator for C-band applications.Design/methodology/approachIn the proposed design, the dual-mode response for the filter is realized with two transmission zeros (TZs) by the insertion of a perturbation element at the diagonal corner of the square patch resonator with orthogonal feed lines. Such TZs at the edges of the passband result in better selectivity for the proposed BPF. Moreover, the cross-loop and square ring slots are etched on a square patch resonator to obtain a miniaturized BPF.FindingsThe proposed dual-mode microstrip filter fabricated in RT/duroid 6010 substrate using PCB technology has a measured minimum insertion loss of 1.8 dB and return loss better than 24.5 dB with a fractional bandwidth (FBW) of 6.9%. A compact size of 7.35 × 7.35 mm2 is achieved for the slotted patch resonator-based dual-mode BPF at the center frequency of 4.76 GHz. As compared with the conventional square patch resonator, a size reduction of 61% is achieved with the proposed slotted design. The feasibility of the filter design is confirmed by the good agreement between the measured and simulated responses. The performance of the proposed filter structure is compared with other dual-mode filter works.Originality/valueIn the proposed work, a compact dual-mode BPF is reported with slotted structures. The conventional square patch resonator is deployed with cross-loop and square ring slots to design a dual-mode filter with a square perturbation element at its diagonal corner. The proposed filter exhibits compact size and favorable performance compared to other dual-mode filter works reported in literature. The aforementioned design of the dual-mode BPF at 4.76 GHz is suitable for applications in the lower part of the C-band.

Configurable pixelated skyrmions on nanoscale magnetic grids

Topological spin textures can serve as non-volatile information carriers. Here we study the current-induced dynamics of an isolated magnetic skyrmion on a nanoscale square-grid pinning pattern formed by orthogonal defect lines with reduced magnetic anisotropy. The skyrmion on the square grid can be pixelated with a quantized size of the grid. We demonstrate that the position, size, and shape of skyrmion on the square grid are electrically configurable. The skyrmion center is quantized to be on the grid and the skyrmion may show a hopping motion instead of a continuous motion. We find that the skyrmion Hall effect can be perfectly prohibited due to the pinning effect of the grid. The pixelated skyrmion can be harnessed to build future programmable racetrack memory, multistate memory, and logic computing device. Our results will be a basis for digital information storage and computation based on pixelated topological spin textures on artificial pinning patterns.

60 GHz dual‐polarized magneto‐electric dipole antenna array with hybrid gap waveguide feeding network in low temperature co‐fired ceramic technology

AbstractA 60 GHz 8 × 8 dual‐polarized aperture‐coupled magneto‐electric (ME) dipole antenna array in low temperature co‐fired ceramic (LTCC) technology is proposed. Taking advantage of the LTCC technology of high integration, the antenna array is composed of three parts, including the wideband ME dipole elements, dual‐polarized strip‐line series feeding network and low‐loss gap waveguide (GWG) feeding network. The ME dipole antenna element is fed by aperture coupling with 45° rotation. Two separate orthogonal strip lines are located right below the aperture to realize dual polarization performance. The simulated −10 dB impedance bandwidth of the dual‐polarized antenna element is 50–66.5 GHz with an isolation lower than −20 dB for two input ports. By employing the proposed radiating element, a 4 × 4 wide‐band dual‐polarized antenna subarray is realized by using strip‐line series‐feed technology. A compact hybrid low‐loss feeding network is realized by combing the GWG technology with the strip‐line series feed technology. For demonstration, one prototype was fabricated. The measured impedance bandwidth is 14.2% and 16.7% respectively for dual polarizations with |S11| &lt; −8 dB, and the port isolation is lower than −20 dB over the entire frequency band of interest.

Dual-Polarized Nonreciprocal Spatial Amplification Active Metasurface

This letter presents a dual-polarized nonreciprocal active metasurface (MTS) for spatial electromagnetic wave amplification. The MTS is designed based on receiving, amplifying, and reradiating scheme. Two square patch antennas printed on the opposite sides of two-layer substrates are used as receiving and reradiating antennas, respectively. A T-shaped microstrip line coupling structure is adopted to achieve impedance matching and dc-block function. Two bipolar transistors, which are place on a pair of orthogonal microstrip feed lines, are used as amplifiers to achieve dual polarization spatial amplification of the electromagnetic wave. A prototype MTS is fabricated and tested to verify the design. The measured effective spatial amplification coefficients higher than 0 dB has a band from 4.88 to 5.19 GHz with the peak value of 10.4 dB. Besides, the proposed MTS is insensitive to polarization. The spatial amplification coefficients variation for different polarization is below 0.6 dB. The proposed MTS could be used in the radio frequency transceiver systems to reduce the pressure of the amplifier on the circuit board.

Supplementary notes on the minimax and orthogonal least squares line fitting procedures

The two-variable orthogonal least squares procedure was developed independently by Julius Ludwig Weisbach (1806–1871) and Robert Jackson Adcock (1826–1895). In this article we discuss aspects of two recent articles concerned with the contributions of these individuals. We also identify a prototype of the orthogonal minimax fitting procedure due to August Beyer (1677–1753).

P42. CT measurement of pelvic incidence in the evaluation of spondylolisthesis

<h3>BACKGROUND CONTEXT</h3> Pelvic incidence (PI) has been described as a parameter that may be a risk factor for lumbar spondylolisthesis. Studies have reported PI measurement is more precise in CT scans. Very limited studies have evaluated PI using CT scans in spondylolisthesis patients. <h3>PURPOSE</h3> Analyze the reliability of CT scans to measure PI in patients with spondylolisthesis compared to patients without spondylolistheses. <h3>STUDY DESIGN/SETTING</h3> Retrospective study from a single, academic center between 2013 and 2016 <h3>PATIENT SAMPLE</h3> A total of 361 patients who had pelvic/abdominal CT scans during an emergency room visit. <h3>OUTCOME MEASURES</h3> Analyze the reliability of CT scans to measure PI in patients with and without spondylolisthesis. <h3>METHODS</h3> The study included patients > 18 years and had no lumbar or pelvis fracture. We documented: age, average PI (right and left) and spondylolisthesis (type, grading and location). Left and right PI were determined on sagittal CT scans measuring the angle between the hip axis to an orthogonal line originating at the center of the superior end plate axis of the first sacral vertebra. Spondylolisthesis grading was determined on sagittal CT scans using Myerding Classification. An average PI (right and left) was calculated using both sides. We categorized patients with spondylolisthesis (n=45) and those without spondylolisthesis (n=316). Subgroups were comprised based on the location of the spondylolisthesis (L4/L5 and L5/S1) and the type of spondylolisthesis (isthmic or degenerative). An ANOVA test was used for continuous variables and Chi-square test for the categorical variables. P≤0.05 was considered as statistically significant. <h3>RESULTS</h3> There was no statistical difference in PI: between patients with and without spondylolisthesis (p=0.29); between subgroups of patients with spondylolisthesis at L4/L5 and without spondylolisthesis (p=0.52); between subgroups with type of spondylolisthesis at L4/L5 and without spondylolisthesis (p=0.47); and between spondylolisthesis patients at L5/S1 and without spondylolisthesis (p=0.40). Patients with isthmic spondylolisthesis at L5/S1 had nearly significant higher PI (p=0.06) compared to without spondylolisthesis and with degenerative spondylolisthesis at L5/S1. There was a trend towards higher PI in Grade 2 spondylolisthesis patients (L5/S1), p=0.18. <h3>CONCLUSIONS</h3> PI was significantly higher in patients with isthmic spondylolisthesis at L5/S1 and a trend toward increased PI with Grade 2 isthmic spondylolisthesis at L5/S1. Our reported PI correlated with PI reported in literature measured using standard radiographs in patients with spondylolisthesis. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Construction of a family of flat curves according to the equations of isometric grids

The article reveals an analytical description of the formation of families of orthogonal flat curved lines in the implicit form based on the analysis of the parametric equation of a flat isometric grid constructed by separating the real and imaginary parts of the function of a complex variable. This problem is due to the fact that flat isometric grids, as two families of orthogonal coordinate lines with square cells, are used in conformal mappings, for example, when drawing images on curved surfaces with the least distortion. At the same time, families of flat parallel lines are widely used in geometric modeling of heat transfer, electric fields, fluid flow, etc. There is a connection between these geometric images, which is explained by specific examples. Analytical calculations of deriving the parametric equation of an isometric grid are quite time-consuming, so they are performed in the environment of symbolic algebra Maple. For this purpose, the corresponding software of the interactive model of derivation of parametric equations of isometric grids for any initial function of a complex variable with the subsequent separation of its real and imaginary parts was created. It was found that the values of the abscissa and ordinates of the parametric equation of a flat isometric grid can be represented as explicit surface equations. For integer values of the power of the exponential function of the complex variable, the values of the abscissa and the ordinate will be represented by algebraic surfaces in the explicit form. The projections of the cross sections of the abscissa and ordinate surfaces by horizontal cutting planes on the horizontal plane form two families of curved lines, the equations of which can be obtained only implicitly. By the example of the quadratic function of a complex variable, it is proved that these families of lines are mutually perpendicular. The practical application of building a family of lines for geometric modeling of fluid flow lines that flow around the barrier in the form of a semicircle is shown. Key words: isometric grids, functions of a complex variable, families of orthogonal lines, geometric flow modeling

The Puzzle of Protest Policing Over Time: Historicizing Repression Research Using Temporal Moving Regressions

Research attempting to predict repression, including the policing of protest, has tended to rely on pooled time series data, which statistically produces coefficients that estimate the average relationship between each variable and the outcome across the entire pooled time period. When relationships are very stable, this statistical assumption, referred to as temporal homogeneity, is unproblematic. But, when enforced without testing, it threatens to artificially “stabilize” temporally heterogenous relationships. In terms of protest policing, this has resulted in relatively ahistorical empirical explanations of protest policing. This article imports modeling techniques from work on identifying historical periods to show how temporal moving regressions can be built to recognize and model temporal heterogeneity in the factors influencing protest policing. We present three important uses for these models: testing exhaustively for temporal heterogeneity in apparently stable findings; testing for temporal heterogeneity that may reconcile otherwise contradictory findings; and inductively combining orthogonal research lines. We demonstrate the utility of each in examinations of protest policing. More generally, we show the potential of temporal moving regressions for uncovering new insights and bringing greater historical sensitivity to research on protest and beyond.

Design of Microstrip Dual-Mode Wideband Bandpass Filter with Controlled Center Frequency and Bandwidth Using Bandstop Filter Topology

ABSTRACT This paper discusses a new method for designing a microstrip dual-mode, sharp skirt, wideband bandpass filter with controlled center frequency and bandwidth from bandstop filter topology. A meander closed loop resonator with directly connected orthogonal feed lines provides a Bandstop filter (BSF) with reduced size. A pair of L-shaped open stubs introduced along the diagonal axis D-D1 realizes a wide passband within the rejection band (0.93–4.13 GHz) of the bandstop filter with sharp stopbands on either side of the passband. Furthermore, the effect of L-shaped open stubs susceptance on passband edges is demonstrated. A quarter wavelength stepped impedance shunt stub (SISS) connected at is proposed to achieve additional transmission zeros in the upper and lower rejection bands to improve the sharpness of filter response. Both center frequency and bandwidth of the proposed filter are controlled by the impedance ratio (R) of the SISS element. The proposed filter is simulated using ADS, fabricated and measured using Vector Network Analyzer (VNA). A good agreement is achieved between simulated and measured results.

Imaging ahead of and around the bit in a desert environment: DrillCAM field trial with wireless geophones and top-drive sensor

Advanced seismic-while-drilling (SWD) technologies are being utilized to steer drilling operations and provide high-resolution subsurface images around and ahead of the bit. We present a case study of SWD imaging using a recently acquired field data set from a desert environment with a complex near surface. Data acquisition is performed with wireless geophones and top-drive sensors using continuous real-time recording. The drill-bit noise data are analyzed while continuously recording in real time by using a specialized workflow that combines elements of SWD and conventional vertical seismic profiling processing with controlled seismic sources. First, the workflow enhances the direct wavefield to retrieve accurate first-break picks for traveltime tomographic inversion along east–west- and north–south-striking walkaway lines. Then, it extracts and enhances upgoing reflection events, illuminating parts of the subsurface around and ahead of the bit. During the final step, these upgoing reflections are imaged using the inverted velocity model to reconstruct a migrated subsurface image around the well. As is the case for land surface seismic in the presence of a complex near surface, we observe a significant variation of data quality for the orthogonal receiver lines. As a result, each line provides a robust image of a different part of the subsurface. The east–west-striking line's migrated image delineates a major shallow reflector that serves as a marker for predicting the drilling depth of a deeper horizon. Likewise, migrating upgoing reflections from the north–south line accurately maps a deeper target horizon ahead of the bit. The obtained SWD images assist in setting the casing points accurately and provide a more precise ahead-of-the-bit depth for different horizons with significantly less uncertainty than surface seismic.

Compact Wideband SRR-Inspired Antennas for 5G Microcell Applications

This communication presents two novel designs of split-ring resonator (SRR)-inspired antennas with a low profile and a wideband response for fifth-generation (5G) microcell application. Two novel SRR structures are first presented and analyzed by their equivalent circuits. Then, an antenna with dual polarization inspired by the SRR is proposed. A thin metallic patch and metallic screws are used to construct this 3-D-SRR structure with low loss and cost. Two orthogonal coupling feed lines are designed to excite the orthogonal polarized radiation. Open stubs on the feeding lines are introduced to generate an additional resonant mode, resulting in an enhanced bandwidth which well covers the 5G-N78 band (3.3-3.8 GHz). Owing to the excellent miniaturization characteristic of the meta-resonator, a dual-polarized antenna with a very compact size of 0.231λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.231λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.044λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is achieved. Its measured peak gain and radiation efficiency are better than 4.7 dB and 83%, respectively. Finally, a circularly polarized (CP) antenna with good CP performance and a compact size is also implemented by the derivative crossed SRR. Overall, these two SRR-inspired antennas not only demonstrate miniaturization advantage but also show good radiation performance, rendering them suitable for the 5G new radio (NR) microcell station applications.