Axial Ratio Research Articles

Experimental study on seismic performance of bridge pier with new HRB650E high-strength steel bar

To facilitate the application of high-strength steel in reinforced concrete bridge structures, this study explores the seismic performance of full-scale HRB650E high-strength reinforced concrete bridge piers. Initially, monotonic tensile tests were conducted on HRB400 and HRB650E steel rebars with the same slenderness ratio to analyze the differences in their mechanical properties. Subsequently, quasi-static cyclic tests were carried out on four square full-scale RC bridge piers to examine the influence of new high-strength rebars, stirrup ratios, and axial load ratios on the seismic performance. Based on the experimental results, a hysteresis model suitable for HRB650E reinforced concrete columns was developed. The findings indicate that the HRB650E steel bar exhibited lower uniform elongation and fracture elongation compared to HRB400 steel bar. The displacement at which HRB650E piers reached crack damage was 36 % higher than that of HRB400 piers, and they also showed lower residual displacements at all load levels. The maximum lateral load capacity and the ductility coefficient of HRB650E piers increased significantly compared to HRB400 piers. While the initial secant stiffness of both types was comparable, HRB650E piers exhibited a slower rate of stiffness degradation, resulting in higher secant stiffness at the ultimate state. They also demonstrated 35 % higher cumulative energy dissipation at the ultimate state. When the stirrup ratio of HRB650E piers was increased from 1.1 % to 1.7 %, there was a slight reduction in residual displacement, a small increase of the yield strength, and a minor improvement in the maximum lateral load capacity. Furthermore, a higher stirrup ratio was observed to improve energy dissipation levels at all loading stages. Increasing the axial load ratio of HRB650E piers from 0.1 to 0.2 allowed the piers to withstand greater deformations at the same repairable ultimate state, with significant increases in yield strength, maximum lateral load capacity, initial secant stiffness, and secant stiffness at the ultimate state, but a small increase in the cumulative energy dissipation. The hysteresis model for HRB650E RC columns, based on experimental data, exhibited good computational accuracy.

Study on seismic response of flexure-shear critical RC columns wrapped with TRC shells

Quasi-static tests were conducted on sixteen specimens to study the seismic response of flexure-shear columns wrapped with textile reinforced concrete (TRC) shells. Two RC square columns served as controls, while the remaining columns were wrapped with TRC shells. Three types of treatment methods were applied to TRC-wrapped columns herein to study the impact of different interfacial treatments on seismic behaviours. This study also analyzed the impacts of shear span ratios, axial load ratios, and number of textile layers on the seismic response of test columns. Results revealed that the TRC confinement layers could mitigate crack development, transforming RC columns' failure modes from flexure-shear to flexure. Due to greater confinement to the concrete core, TRC-wrapped columns exhibited enhanced performances compared to control columns, with peak loads, ductility, and cumulative energy dissipation increasing by up to 49.9%, 195.3%, and 5.7 times, respectively. TRC confinement layers could mitigate the shear effects in column specimens. TRC wrapping could improve the shear capacities of flexure-shear columns, with growth rates ranging from 25.2% to 60.4%. Eventually, an equivalent viscous damping model was proposed to assess the energy dissipation capacity of flexure-shear columns wrapped with TRC shells.

Compact circularly polarized metasurface antenna based on characteristic mode analysis

AbstractThis article introduces a novel, single‐layer, low‐profile, circularly polarized metasurface antenna. Through characteristic mode analysis, the optimization of a 33 rectangular metasurface structure was performed. Two orthogonal modes were selected as the operating modes, and improvements to the metasurface structure were made to achieve a 90 phase difference between these modes. The adoption of a coplanar waveguide structure enables the excitation of the metasurface, facilitating circularly polarized radiation performance for the two selected modes. The antenna's dimensions are 40 mm 40 mm 3 mm (0.67 0.67 0.05 ), featuring a −10 dB impedance bandwidth of 27.8% (4.49–5.94 GHz). The 3 dB axial ratio bandwidth is 14.2% (5.25–6.05 GHz), with a maximum gain of 7.26 dBi.

Predictors of Benignity for Small Endophytic Echogenic Renal Masses.

To evaluate for distinguishing demographic and sonographic features of small (<3 cm) endophytic angiomyolipomas (AMLs) that differentiate them from endophytic renal cell carcinomas (RCCs). This is a Health Insurance Portablitiy and Accountablity Act (HIPAA)-compliant retrospective review of the demographics and ultrasound features of endophytic renal AMLs compared to a group of endophytic RCCs. AMLs were confirmed by identifying macroscopic fat on computed tomography (CT) or magnetic resonance imaging (MRI), while RCCs were pathologically proven. Statistical analysis was used to compare findings in the 2 groups. There were a total of 66 patients with 66 AMLs, and 28 patients with 28 RCCs. Of the AMLs, 57 of 66 were in females, while 10 of the 28 RCC cases were in females (P < .0001). The mean AML long and short diameters were 11.0 × 9.3 mm and were statistically significantly smaller (P < .0001) than the diameters of the RCCs (23.4 × 22.1 mm). Likewise, the ratio of the long axis to the short axis measurement was statistically significantly different between the 2 groups (P < .0001). Of the studied sonographic features, statistically different features between AMLs and RCCs included an oval versus a round shape (P < .001), respectively, and the presence versus absence of an echogenic margin, respectively. Location of the mass, mass homogeneity, mass lobulation, and presence of cystic components were not distinguishing features using P < .01 levels. For an endophytic echogenic mass in a female patient, a small size with an oval shape and an echogenic margin is statistically more likely to be an AML than an RCC, which may be helpful with management decisions.

Seismic Performance of the Bridge Piers Reinforced with PP-ECC in the Plastic Hinge Region

Ductility deficiency in reinforced concrete (RC) piers is a substantial factor contributing to earthquake damage in bridge structures. In this study, the conventional concrete in the potential plastic hinge area was substituted with polypropylene fiber-reinforced engineered cementitious composite (PP-ECC), thereby leveraging its high ductility characteristics to explore the seismic performance of RC piers strengthened by PP-ECC. A finite element model was established to discuss the reinforced height, axial compression ratio, longitudinal reinforcement ratio and stirrup ratio on the hysteresis performance by referring to a published paper with a 1/5 scale test specimen. Based on the results of the parameter analysis, an ideal set of configuration parameters was proposed. Subsequently, a full-size simplified mechanical model was established with ideal reinforcement parameters. Time-history and pushover analysis were utilized to test the seismic response. The study indicates that the two analytical methods were largely consistent. The improvement in the displacement and shear force of the strengthened pier gradually decreased with the increase in acceleration amplitude. Time-history analysis reveals a decrease in the enhancement of displacement from 82.26% to 17.98% and a reduction at the bottom reaction from 12.2% to 1.5%. Under the pushover analysis method, the retrofitting level of the top displacement decreased from 77.22% to 11.53%, whereas the improvement level of the bottom shear decreased from 9.62% to 3.69%. These results provide a theoretical basis and reference standard for the application of PP-ECC.

Implantable small ultra-wideband circularly polarized antenna design for continuous blood pressure monitoring

This paper presents a miniaturized circularly polarized (CP) implantable antenna Ultra-wide bandwidth for continuous blood pressure monitoring. The miniature and CP of the antenna are gained by using a new slot method. The symmetry slots in the radiation patch, two T-shape slots in the GND, coupled with the use of a short pin make the designed antenna with good physical and radiation properties. In simulation, the fractional effective axial ratio bandwidth is 23.6% (2.36–2.94 GHz), and the peak gain is − 28.9 dBi. Its total size is only 17.78 mm3 (0.056 × 0.04 × 0.004 λ03), which size is smaller compared to other antennas with similar performance. A prototype is fabricated and measured. The experimental results are in good agreement with the simulation results. And, the radiation patterns have good symmetry both in the simulation and measurement. In addition, the maximum SAR value is in accordance with the IEEE standard safety guidelines (IEEE C95.1-2019).

Seismic Performance of Precast Drift-Hardening Concrete Walls Connected by Grout-Sheath Duct.

In order to find a suitable size of sheath duct and a reliable construction method for precast walls, a cast-in-place and five 1/2 scale precast drift-hardening concrete walls reinforced with weakly bonded ultra-high strength SBPDN rebars were fabricated and tested under reserved lateral load and constant compression. The experimental variables were the diameter of sheath ducts (45 mm, 100 mm, and 120 mm), embedded length (20d and 35d; d is the nominal diameter of SBPDN rebars), axial load ratio (0.075 and 0.15), and the construction method. The experimental observations, hysteresis behaviors, envelope curves, residual deformation, crack propagation, and energy dissipation were compared in the study. Moreover, a formula was applied to calculate the bond strength of the sheath duct. The experimental and calculated results revealed that increasing the axial load ratio and embedment length could not enhance the bond strength of the sheath ducts, and increasing the diameter decreased the bond strength significantly. Anchored the SBPDN rebars in smaller sheath ducts separately was a more stable connection method for precast concrete shear walls and provided sufficient drift-hardening capability, even at a large drift level (over 3%).

Equilibrium dynamical models in the inner region of the Large Magellanic Cloud based on Gaia DR3 kinematics

The Large Magellanic Cloud (LMC) contains complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depend on the stellar, gas, and dark matter mass distributions. Despite this complexity, simple physical models often provide valuable insights into the primary driving factors. We used Gaia Data Release 3 (DR3) to explore how well equilibrium dynamical models based on the Jeans equations and the Schwarzschild orbit superposition method are able to describe the LMC's five-dimensional phase-space distribution and line-of-sight (LOS) velocity distribution, respectively. In the Schwarzschild model, we incorporated a triaxial bar component for the first time and derived the LMC's bar pattern speed. We fit comprehensive Jeans dynamical models to all Gaia DR3 stars with proper motion and LOS velocity measurements found in the footprint of the VISTA near-infrared survey of the Magellanic System using a discrete maximum likelihood approach. These models are very efficient at discriminating genuine LMC member stars from Milky Way foreground stars and background galaxies. They constrain the shape, orientation, and enclosed mass of the galaxy under the assumption of axisymmetry. We used the Jeans model results as a stepping stone to more complex two-component Schwarzschild models, which include an axisymmetric disc and a co-centric triaxial bar, which we fit to the LMC Gaia DR3 LOS velocity field using a $ minimisation approach. The Jeans models describe the rotation and velocity dispersion of the LMC disc well, and we find an inclination angle of $ circ circ $, line of nodes orientation of $ circ circ $, and an intrinsic thickness of the disc of $q_0^d = b a (minor to major axis ratio). However, bound to axisymmetry, these models fail to properly describe the kinematics in the central region of the galaxy dominated by the LMC bar. We used the derived disc orientation and the Gaia DR3 density image of the LMC to obtain the intrinsic shape of the bar. Using these two components as input to our Schwarzschild models, we performed orbit integration and weighting in a rotating reference frame fixed to the bar, deriving an independent measurement of the LMC bar pattern speed of $ Both the Jeans and Schwarzschild models predict the same enclosed mass distribution within a radius of $6.2$\,kpc of $ Msun.

Simplified calculation models for evaluating the post-earthquake axial load-carrying capacity of RC bridge piers

This study aims to develop simplified calculation models of the post-earthquake axial load-carrying capacity of reinforced concrete columns to determine the post-earthquake traffic flow capacity of the bridges for the evaluation and design process. To this end, the maximum and residual drift ratios are first determined as the engineering demand parameters for the simplified calculation model for the evaluation and design process, respectively. Then, the optimal models describing the relationships between the maximum/residual drift ratio and the post-earthquake axial load-carrying capacity are selected. The analysis results show the normal cumulative model in the coordinate system of ln(x)-y is the optimal relationship model. On this basis, the effects of high-sensitivity parameters (i.e. the axial compressive ratio and shear span ratio) on the post-earthquake axial load-carrying capacity are investigated. Results indicate that the axial compressive ratio negatively affects, while the shear span ratio positively affects the post-earthquake axial load-carrying capacity. Finally, the simplified calculation models of the post-earthquake axial load-carrying capacity are developed from the optimal model and the effects of the high-sensitivity parameters, and with validated high accuracy. The simplified calculation models provide engineers and policymakers with a tool to predict the post-earthquake traffic flow capacity of bridges.

Dynamic range extension method for sinusoidal phase modulating interferometer based on in-phase component signal reconstruction

Abstract The continuous increase of the amplitude of the measured vibration will cause spectrum aliasing in the interference signal of the sinusoidal phase modulating interferometer (SPMI), thereby constraining its measurement dynamic range (DR). To address this issue, a dynamic range extension method of SPMI based on the reconstruction of in-phase component signal is proposed. On the basis of conventional SPMI, an additional reference signal is introduced for estimating the phase modulation depth (PMD) and the major to minor axis ratio Re of the Lissajous ellipse formed by orthogonal interference signal pair and a phase demodulation algorithm named as PGC-ICR-DCM which integrates PGC-DCM algorithm and the in-phase component signal reconstruction (ICR) is proposed. Initially, the PMD is regulated to approximately 1.8412 rad, ensuring that the quadrature component signal can be accurately extracted from the mixed signal of the interference and carrier signals, even in the presence of spectrum aliasing in the original interference signal. Then, the undistorted quadrature component signal is used to reconstruct an in-phase component signal with the estimated value of Re. Finally, the reconstructed in-phase component signal and quadrature component signal are normalized, and a differential-and-cross-multiplying algorithm (DCM) is applied to obtain the measured vibration. A SPMI measurement system based on Michelson interferometer structure is constructed to experimentally validate the proposed method. The experimental results demonstrate that the proposed method can effectively extend the DR of the SPMI system in the presence of spectrum aliasing. The DR of the system is increased from 97.52 dB @ 55 Hz to 102.6 dB @ 55 Hz, with the maximum measurable amplitude increasing from 7728.75 nm @ 55Hz to 13705.16 nm @ 55 Hz.

Effect of a reduced arterial axial pre-stretch ratio during aging on the cardiac output and cerebral blood flow in the healthy elders

Background and objectiveIt is an indisputable physiological phenomenon that the arterial axial pre-stretch ratio (AAPSR) decreases with age, but little attention has been paid to the effect of this reduction on chronic diseases during aging. MethodsHere we reported an experimental method to simulate arteries aging, developed a fluid-structure interaction model with the effect of AAPSR changes, and compared it with the anatomy data and structural parameters of the human thoracic aorta. ResultsWe showed that with the process of aging, the decrease of AAPSR leads to a decline of arterial elasticity, a decrease of arterial elastic strain energy, which weakens the ability to promote blood circulation, the corresponding decrease in cardiac output (CO) and cerebral blood flow (CBF) causes distal organ and body tissue ischemia, which is one of the main causes of increased blood pressure and decreased cerebral perfusion in the elderly. ConclusionsThus, reduced AAPSR is the one of main manifestation of arteries aging and has an important impact on hypertension and hypoperfusion of the brain in the process of human aging. The research contributes to a better understanding of the physiological and pathological mechanisms of aging-related diseases.

Numerical Study on the Retrofitting of Exterior RC Beam-column Joints with CFRP Composites Using the Grooving Method

Retrofitting seismically deficient beam-column joints (BCJs) in reinforced concrete (RC) structures is crucial to preventing collapse during high-intensity earthquakes. Fiber reinforced polymer (FRP) composites have proven effective for retrofitting these components, but debonding of the FRP from concrete surfaces remains a challenge. Recently, the grooving method (GM) has emerged as a promising solution to mitigate this issue, enhancing the bond between FRP and concrete. This paper presents a numerical investigation of BCJs retrofitted with FRP composites using the GM, focusing on various design parameters. The study utilized finite element models developed in ABAQUS, incorporating the concrete damage plasticity (CDP) model to simulate the nonlinear behavior of concrete. The interface between the concrete and FRP was modeled as a perfect bond, simulating the strong adhesion provided by the GM. The numerical results were validated against experimental data from two BCJ specimens, showing good agreement in terms of load-displacement behavior, peak loads, and failure modes. Key parameters studied include the beam longitudinal reinforcement ratio, column axial load ratio, and joint aspect ratio. The findings reveal that these parameters significantly affect the shear capacity of retrofitted joints, impacting the efficiency of the retrofitting.

A modified dumbbell-shaped highly efficient broadband multifunctional polarizer for X and Ku band applications

Abstract A novel metasurface offering polarization conversion characteristic in five bands is studied and developed in this paper. To provide the anisotropic feature to the structure, a diagonally placed tapered rod is combined with two semicircular stubs. Due to the controlling ability to convert horizontal to vertical polarization and vice versa, and linear to circular polarization (CP), it serves as a multifunctional polarization converter. Simulation results suggest that the proposed polarizer functions as cross polarizer over 4.74−5.12 and 9.12−13.48 GHz. Additionally, it exhibits a distinct type of rotational sense across 4.24−4.68, 5.24−8.64, and 13.72–15.14 GHz in its linear to CP conversion behavior. The axial ratio of the polarizer is well below 3 dB throughout overall CP bands due to the minimum tolerance level in reflection phases with respect to acceptable limits. Moreover, it is noticed that the sense of CP is left-handed in the first band while right-handed in the remaining two bands. Thus, the suggested polarizer has potential to be integrated with antennas for satellite, defense, industry applications for getting the desired type of polarization in the distinguished bands.

Seismic in-plane behavior of composite masonry walls strengthened with cold rolled steel sheets

The seismic behavior of masonry walls strengthened by cold rolled steel sheets is numerically evaluated in this study using finite element modeling in ABAQUS. Cold-rolled steel sheets cover two sides of an unreinforced masonry wall and are bolted together to form a composite masonry wall. The behavior of the composite masonry walls is compared to that of the corresponding unreinforced masonry walls with various failure mechanisms. The finite element models of the unreinforced masonry walls are validated through experimental data in the literature. Then, cold-rolled steel sheet-strengthened walls are simulated, and variations in strength, ductility, and failure mode are investigated. A thorough sensitivity analysis is conducted on the effects of the aspect ratio, boundary condition, axial load ratio, steel sheet thickness, and connection bolt configuration on the in-plane strength and failure mode of the walls. It is observed that the steel sheets affect the local and global behavior of the masonry walls and change their failure modes. The use of through-thickness bolts to connect steel sheets to the masonry wall provides a composite action between steel sheets and the masonry wall against in-plane lateral loads. The cold-formed steel sheets not only resist a portion of the lateral load but also significantly increase the lateral strength of the masonry walls and the ductility of the whole wall system. Based on the analysis results it can be concluded that strengthening masonry walls with cold-rolled steel sheets is a promising technique for the seismic improvement of existing conventional masonry buildings and for the design of new masonry buildings.

Review on Intrinsic Shape of Elliptical Galaxies

: Elliptical galaxies, as one of the fundamental types of galaxies, have attracted astronomers due to their intriguing properties. In this review, we explore the intrinsic shape of elliptical galaxies, a field that plays a pivotal role in understanding their formation, evolution, and interactions within the cosmos. Methods for intrinsic shape determination using photometric and kinematic methods are extensively discussed. The use of photometric data and surface brightness profiles to derive the intrinsic shapes of elliptical galaxies is examined and triaxial models are reviewed. Constraining the intrinsic shapes of elliptical galaxies is crucial to understanding their formation histories. Elliptical galaxies are characterized by their ellipsoidal, rather than disk-like, shapes, and understanding the underlying factors and their intrinsic shapes of elliptical galaxies determination provides valuable insights into their formation, evolution, and the broader context of galaxy morphology. One key aspect of studying the intrinsic shape of elliptical galaxies involves the analysis of their axial ratios, which describe the flattening of the galaxy along different axes. The axial ratio is defined as the ratio of the semi-minor axis to the semi-major axis of the ellipse representing the galaxy's cross-section. The intrinsic shape can vary from nearly spherical (axial ratio close to 1) to highly elongated (axial ratio significantly different from 1).

A metasurface for linear-to-circular polarization conversion and sensing based on quasi-BIC

This work presents a multifunctional metastructure (MS) which realizes linear to circular polarization conversion and sensing function based on quasi-bound states in the continuum (quasi-BIC). MS is made of silicon dioxide as substrate, and silicon as surface material, by etching cross holes and square holes on it to form a 2 × 2 structure, through the transmission of terahertz (THz) band, to form an ultrahigh quality factor (Q-factor), and realize the conversion of linearly polarized waves to circularly polarized ones. At 178.190 THz, it achieves a Q value of 2969, and in the range 178.193 TH to 178.200 THz, the axial ratio (AR) is less than 3 dB and the insertion loss is less than 0.0001. In addition, by changing the permittivity of the surrounding environment, the minimum of the output wave will produce a good linear frequency shift. Using this feature, the given device can also be used as a dielectric constant sensor to detect air quality. The device has a sensing sensitivity (S) of 6.415 THz RIU−1 and a figure of merit (FOM) of 106.9. The parameters (H, w2, L2, g2), incidence angle (θ) and the polarization angle (φ) are discussed. The effects of different parameters on the Q-factor and AR were analyzed, which helped to select the optimal parameters. The design can also be used in communication and biosensing.

Combined bending-torsion and compression-bending-torsion behaviours of reinforced concrete-filled thin-walled corrugated steel tubes

Reinforced concrete-filled thin-walled galvanized corrugated steel tube (RCFCST) is a novel composite member that has application potential in extremely corrosive environments and seismic activity regions. A series of preliminary works have been conducted on its compressive, flexural, shear, and torsional behaviour. However, the combined loading condition is almost inevitable in practice. The correlations between the flexural and torsional behaviour of RCFCSTs are unique due to the special spiral corrugated profile, which is unclear and needs to be addressed. This paper, therefore, presents an experimental investigation of the RCFCST under combined bending-torsion and compression-bending-torsion loads, encompassing the main test variables of torsion-to-bending ratios, torsional directions, and axial compression ratios. The loading set-up and instruments have been introduced in detail. The failure modes, lateral load versus lateral displacement curves, bending moment versus flexural lateral displacement curves, torsion moment versus torsional angle curves, and strain distributions are carefully addressed. The working mechanisms of the RCFCST under monotonic combined loads are discussed, with a particular explanation of the dependent behaviour on the torsion-to-bending ratios and torsional directions. The applicability of the existing design methods for the bearing capacity of RCFCST specimens under combined loads is examined carefully, with specific design suggestions proposed.

A wideband dual-circularly polarized traveling wave dielectric resonator antenna array

ABSTRACT In order to meet the demand of high capacity and high speed transmission of satellite communication system, a wideband dual-circularly polarized dielectric resonator antenna (DRA) array is proposed based on the traveling wave principle. Four DRA elements with slot-coupling excitation are sequentially placed on the ground, and the feeding network is designed to realize the two orthogonal circular polarization radiation waves. A notched copper loop (NCL) around the antenna array is adopted to improve the radiation performance. Depending on the operation of the two ports, the NCL generates the induced currents which rotates clockwise/counterclockwise, increasing the axial ratio bandwidth. In order to further improve the gain stability, the copper sheets are embedded on the top surface of each radiation element, and the copper cylinders perturb the internal field distribution of the DRA to introduce higher-order modes. The measurement results show that the left-hand circular polarization and the right-hand circular polarization operating bandwidths are 11.8% (14.97–16.85 GHz) and 12% (14.91–16.82 GHz). The antenna gain achieves 9.0 dBic. This DRA array can be applied for the vehicle mounted RF terminals in satellite communication.

A novel circularly polarized antenna array methodology for early identification of kidney tumors

Kidney cancer is a significant health concern worldwide, with early detection crucial for successful treatment outcomes. Recently, there has been an increasing focus on investigating affordable and non-intrusive methods for detecting cancer at its early stages. This proposed approach delves into the utilization of antenna arrays to identify kidney cancer. Specifically, antenna array with circular polarization has been crafted to identify tumors in the human kidney. This array design has been implemented using CST software, operating at 2.4 GHz. The antenna array having a dimension of 150 mm x 150 mm. The array consists of four-square patches each having a length of 30 mm and the spacing between the patches is preferred to be 20 mm for ensuring the mutual coupling. FR4 substrate is used with the relative permittivity 4.3 and 1.6 mm thickness. The axial ratio of the circularly polarized antenna is 0.9 dB at 2.4 GHz. The reflection coefficient S 11 = –30dB. The renal phantom in humans has been built with the kidney, adrenal gland, ureter, skin, fat, and muscle components to allow for precise simulation. Following that, four stages of cancer tumors were built employing all of the necessary qualities. For every stage of the cancer tumor, the reflection coefficient growth and resonance frequency shift are calculated. For the initial stages, the resonance frequency shift is very low. Consequently, the primary determinant of detection is the rise in S 11 . For 3rd and 4th stages of the tumor, there is a significant change in resonance frequency and increase S 11 , which facilitates identification. The calculated specific absorption rate (SAR) is a smaller amount than the safety thresholds, indicating that using this method is safe. Overall, this research points to a novel, easy-to-use method for kidney cancer screening. This method has the following benefits: it is non-invasive, safe, quick, affordable, and comfortable, and it emits no ionizing radiation during the measurement process. Furthermore, a range of output parameters such as gain, directivity, and polar radiation have been accurately computed.

A single-feed circularly polarized antenna with a low vertical profile and hemispherical axial-ratio beam coverage

ABSTRACT A novel wide axial-ratio beamwidth (ARBW) circularly polarized (CP) antenna with a single layer substrate fed by a single probe is proposed. It consists of an inner annular slotted radiator containing eight outer sector units with arc branches, a ground plane, and eight grounded vias. The antenna has an ARBW covering the upper hemisphere and has a low vertical profile. The ultra-hemispherical ARBW is formed by ingeniously merging the endfire omnidirectional CP radiation pattern with the boresight CP radiation pattern. The two radiation patterns can be excited by a central coaxial probe without an additional feeding network. An antenna prototype of dimensions 1.15 × 1.15 × 0.02 (λ 0 3) is fabricated and measured to validate the design concept. Measured results show that the impedance bandwidth of the proposed antenna is 2.0% (3.328–3.394 GHz) and the 3 dB axial ratio (AR) bandwidth is 1.3% (3.332–3.374 GHz). The 3 dB AR beamwidth can cover more than 217° and the maximum gain is 0.79 dBic at 3.35 GHz. A good agreement between the simulated and measured results is obtained.