Upper Band Research Articles

Finite-element simulation of pressure profile and 3D deformation of breasts wearing adjustable bras

Adjustable bras should be well designed with scientific analysis of pressure distribution to maintain a balance between the multidimensional considerations of comfort, function, and safety. A contact mechanics model of a body-adjustable brassiere was developed, with the aim of investigating the interaction between these considerations, and of further scientifically optimizing the pattern design and fabric selection. Point cloud data were obtained through 3D body scanning, and the torso surface was reconstructed using a detection contour method. A geometric model of the torso was divided into soft tissue, thorax, and breast by reverse engineering; the brassiere geometric model, in the semi-dressed state, was divided into eight parts and constructed using forward–reverse methods. The breast and soft tissue were considered as linear elastic entities with different material parameters, the thorax was taken to be a rigid body, and the brassiere was modeled as a linear elastic shell with variable components and material parameters. The simulation was validated by pressure measurement and shaping evaluation in vivo. Results show that the model could be used to predict the contact pressure and 3D deformation with reasonable accuracy. The contact pressure at the top of the shoulder is 4.9–7.8 kPa, that at the underband is 1.9–4.9 kPa, and that at the upper band is 1.0–2.9 kPa. The pressure on the breasts is mainly concentrated in the lower half of the breasts, and ranges from 0.1 to 1.5 kPa. The finite-element model developed in this study helps to provide a better understanding of the complex interactions between the body and an adjustable brassiere, and can be used to analyze different bra design features (fabric parameter, pattern, etc.) for predicting the pressure distribution and deformation of breast shapes.

Wide Stopband Bandpass Filter With Higher‐Order Mode Suppression

ABSTRACTTo meet the requirement of band selection performance and low loss in wireless communication system, a wide stopband bandpass filter with higher‐order mode suppression is proposed in this paper. The filter utilizes the high‐pass characteristic of the Half Mode Substrate Integrated Waveguide (HMSIW) to produce a lower stop‐band. A quarter‐wavelength resonator is used to generate a transmission zero at the upper band. Thus, the bandpass effect is realized from 3.4 to 5.6 GHz. The 3 dB relative bandwidth reaches 46.7%, the in‐band insertion loss is less than 0.7 dB, and the return loss is better than −15 dB. The transverse slots of the resonant part cut the surface current flow and effectively suppress the higher‐order TE mode; the additional metal vias near the electric wall are equivalent to the inductors for storing magnetic energy, which reduce the harmonic interference of higher‐order TM modes. The −25dB stopband of the filter is from 6.5 to 17 GHz, thus a wide stopband of 3.7 times of center frequency is realized. The measured results are well matched with simulated ones. The filter has the characteristics of simple structure, low profile, low loss, and easy fabrication, which provides a novel concept for the design of high‐performance filtering devices in radar and aerospace systems.

Single-photon scattering under control of artificial gauge field

The mechanism of controlling single-photon scattering in a hybrid system consisting of superconducting qubits coupled to aSu-Schrieffer-Heeger (SSH) topological photonic lattice is investigated under the influence of an artificial gauge field. This research is driven by the growing interest in the intersection between quantum optics and condensed matter physics, particularly in the field of topological quantum optics, where the robustness of photon transport against defects and impurities can be used for quantum information processing. To achieve this, a theoretical model, which incorporates the phase of the artificial gauge field into the coupling between superconducting qubits and the SSH photonic lattice, is developed in this work. The analytical expressions for the reflection and transmission amplitudes of single photons are derived by using the probability-amplitude method. The results show that the artificial gauge field can effectively control single photon scattering in both the upper energy band and the lower energy band of the SSH lattice, thereby enabling total transmission in the upper band and total reflection in the lower band. This band-dependent scattering behavior exhibits a high degree of symmetry with respect to the lattice momentum and energy bands. Importantly, the reflection coefficient can be made independent of the lattice coupling strength and dependent solely on the topological properties of the lattice. This finding suggests a robust method of detecting topological invariants in photonic lattices. Furthermore, our analysis is extended to various coupling configurations between superconducting qubits and the photonic lattice, highlighting the versatility of the artificial gauge field in manipulating photon transport. These findings not only provide new insights into the control of photon transport in topological photonic lattices, but also open the door to the development of novel quantum optical devices and robust quantum information processing platforms.

INNOVATIVE PATCH ANTENNA DESIGN WITH ENG MATERIALS FOR 5G AND HEALTHCARE APPLICATIONS

This paper introduces a novel microstrip patch antenna utilizing Epsilon-negative (ENG) metamaterials and L-shaped parasitic elements. The antenna achieves dual-band operation by incorporating four vertical metal vias along the patch antenna's boundaries. In patch mode or at the upper frequency band, circular polarization is attained by adding Minkowski fractal edges to the corners of the four-way patch design. The inclusion of L-shaped parasitic patches enhances the bandwidth in both frequency ranges. At the upper and lower resonant frequencies, a 10 dB bandwidth enhancement of 27.84% (2.88 – 3.81 GHz) and 6.11% (2.22 – 2.36 GHz) was achieved, respectively. When applying a 3 dB axial ratio in the upper band, the bandwidth is 5.05% (2.90 – 3.05 GHz). The accuracy of the antenna can be validated by comparing simulation results with experimental measurements. This innovative antenna design offers greater efficiency, lower cost, ease of integration, and provides faster, more reliable communication, making it particularly suitable for healthcare applications and 5G technology.

Ultra-miniaturized HMSIW cavity-backed reconfigurable antenna diplexer employing dielectric fluids with wide frequency tuning range

This communication presents an ultra-miniaturized two-way frequency tunable antenna diplexer based on cavity-backed slots and dielectric fluids. The proposed antenna utilizes two half-mode substrate-integrated rectangular cavities loaded with slots and fluidic pockets. The conventional size reduction is achieved by employing half-mode cavities, whereas ultra-miniaturization is obtained by applying the slots, which provides additional capacitive loading. As the cavities are of unequal sizes, a weak cross-coupling path is created between the ports to obtain high isolation (> 30 dB). The isolation is further enhanced by loading the slots. Two mechanisms are analyzed to tune the frequency bands individually or simultaneously. Firstly, the width of the slots can be altered to tune the frequency bands. However, this method involves modification of the physical dimensions of the antenna. Secondly, fluidic vias are created on the bottom plane of the cavities. These can be filled with various dielectric liquids to achieve frequency reconfigurability without altering the physical dimensions of the antenna. To demonstrate the concepts considered, the prototype of the proposed antenna was fabricated and experimentally validated. The structure has a footprint of 0.045λg2 and an isolation exceeding 33.4 dB. The operating frequencies are tunable in the range from 3.08 to 3.84 GHz (lower band) and from 4.97 to 6.33 GHz (upper band) by varying the dimensions of the slots whereas the operating frequencies are reconfigurable in the range from 2.74 to 3.38 GHz (lower band) and from 4.54 to 5.58 GHz (upper band), by employing microfluidic approach. As a result, the working frequencies may be varied in the range from 2.74 to 3.84 GHz (lower band) and from 4.54 to 6.33 GHz (upper band), making this antenna diplexer a competitive candidate for several communication systems. The cross-polarization levels, front-to-back ratio, and realized gain are greater than 19 dB, 18 dB, and 2. dBi, respectively. Excellent consistency is observed between full-wave simulation results and the measurement data.

Pixelated slot-based dual-broadband tunable graphene metasurface absorber design through excitation of coupled modes in terahertz regime

Pixelated slot-based dual-broadband tunable graphene metasurface absorber design through excitation of coupled modes in terahertz regime

Compact dual-band enhanced bandwidth 5G mm – wave MIMO dielectric resonator antenna utilizing metallic strips

Compact dual-band enhanced bandwidth 5G mm – wave MIMO dielectric resonator antenna utilizing metallic strips

Miniaturized IPD band pass filter with low insertion loss based on modified T‐section for 5G applications

AbstractA miniaturized bandpass filter (BPF) with low insertion loss based on a modified T‐section and a grounded transmission‐zero resonator is proposed. The novel T‐section consists of two resonators, which can achieve the bandpass performance with two transmission zeros (TZs) in the upper band. The grounded transmission‐zero resonator can generate an extra transmission zero in the lower band. Therefore, high frequency selectivity can be achieved by the above three transmission zeros near the passband. The proposed BPF can achieve an insertion loss of 0.8 dB and a return loss of 22 dB covering 3.3–4.2 GHz, and the upper‐stopband attenuation is better than 20 dB up to 12.5 GHz (3.3f0). The proposed BPF with a miniaturized size of 1.2 mm × 0.5 mm × 0.3 mm have been fabricated using Si‐based integrated passive devices (IPDs) technology and measured by on‐wafer probing. The simulated and measured results of the proposed BPF are in reasonably good agreement.

Litar Setara Dwi Jalur Antena Dwikutub Bersepadu untuk Aplikasi RFID

This paper presents dual band antenna by designing basic dipole antenna integrated with C-shaped patches structure for RFID applications. This C-shaped patch is inspired by E-shapes patch antenna that able to perform multiband frequency. The design of the equivalent circuit started with the fundamental circuit of impedance Zo and Z1 which functioned as a dipole antenna in single band. The parallel RLC circuit of impedance Z2 is added in the circuit as loaded patch has affected the resonating frequency. Variations of C1 and L1 on impedance Z1 effect a gap between the two resonance frequencies without changing the bandwidth by shifting the lower frequency. In addition, the variation of C2 and L2 on the impedance Z2 also affects the ratio between the two resonance frequencies but both frequencies are shifted and the bandwidth changes. Consequently, the dual band is presented at 0.915 GHz (UHF RFID) and 2.4 GHz (ISM RFID) by calculating the value of the resistance, inductance and capacitance. The data from electromagnetic simulation are compared with the data predicted by the antenna circuit modeling. The frequency sampled measurement data may be represented in the form of S-parameter in order to represent dependent data in a time domain simulator in P-SPICE software. The C-shaped design can be independently controlled to perform lower band and upper band by adjusting the width and length of the patch. The performance of the proposed antenna demonstrates the dual band antenna for RFID application with good agreements between measured and simulated results.

Two bits dual-band switchable terahertz absorber enabled by composite graphene and vanadium dioxide metamaterials

This article presents the design of a 2-bit dual-band switchable terahertz absorber using a stacked combination of graphene and vanadium dioxide (VO2) metamaterials. For the first time, the proposed absorber design offers four switchable states by controlling the conductivity of graphene and VO2 metamaterial layers. The lower absorption band is produced by the graphene metamaterial, whereas the upper band is implemented by the VO2 metamaterial pattern. The structure shows two absorption bands (State 11) at 0.745–0.775 THz and 2.3–5.63 THz, when the Fermi graphene level of graphene is 0.2 eV and the VO2 is in the metallic phase. The lower absorption band is turned off, while keeping the upper band (State 01), when the graphene Fermi level is 0 eV and the VO2 layer is in the metallic phase. The upper absorption band is turned off, while preserving the lower absorption band (State 10) by switching the VO2 into the insulator phase and keeping the graphene Fermi level at 0.2 eV. Finally, both of the absorption bands are turned off by setting the graphene Fermi level to 0 eV and switching the VO2 into the insulating phase. Equivalent circuit modelling analysis and full-wave electromagnetic simulations are used to explain the operation principle of the proposed absorber. Very good agreement is obtained between the theoretical analysis and the simulations confirming the presented design principle for the 2-bit switchable absorber.

A Low-Cost Patch-Antenna for Non-Invasive Brain Cell Detection

Cancer is one of the most and frequent causes of death around the world. Brain tumor is a critical and dangerous type and has a few difficulties of the techniques used for its detection; it is hard to determine its location when it is small at an early stage. The purpose of this work is to design a patch antenna sensor that is a low-cost microstrip which is suitable to detect a brain cancer tumor. The computer simulation technology CST Studio Suite 3D EM simulation and analysis was used to design a patch antenna with different frequencies of 2.8 GHz, 3.9 GHz, 5GHz and 5.6GHz to diagnose brain tumors. A comparison study between these resonance frequencies (lower-band (L-B) 2 GHz, middle-band (M-B) 3.9-5 GHz and upper-band (U-B) > 5 GHz) has been performed with six layers of brain phantom of fat, dura, brain, skin, CSF (Cerebrospinal Fluid) and skull. The designed patch sensor was assessed on both scenarios without and with a tumor cell on a brain phantom. Three parameters have been observed, the frequency phase shift, the deep amount of reflection return loss and power absorption were used to indicate the presence of the tumor cell. This study concludes that the middle-band (M-B) results in good penetration and better return loss depth around - 20dB. Meanwhile, the higher band provides high resolution of 21 MHz phase-shift but with only depth value of difference return loss of -0.1dB. The proposed work could provide a pathway on the design of patch sensors for biomedical applications.

Broadband circularly polarized filtering patch antenna based on metasurface

AbstractIn this paper, a single‐fed broadband circularly polarized (CP) filtering patch antenna based on metasurface is proposed. It consists of a corner‐truncated square patch, a nonuniform metasurface, and a U‐shaped strip. By placing the metasurface above the driven patch antenna, a radiation null is realized at the upper band, and an additional axial ratio (AR) minimum is simultaneously generated to enhance the CP bandwidth. Besides, two more radiation nulls are achieved at each side of the band edges by introducing a U‐shaped strip underneath the patch and embedding a shorting pin into the patch, which further improves the frequency selectivity and suppresses the radiation level. Measured results show that the designed antenna has a wide impedance bandwidth of 19.7% (4.8–5.85 GHz), a CP bandwidth of 19.9% (4.75–5.8 GHz), and an in‐band average gain of 7 dBic with suppression level of more than 18 dB at out of band.

Multi-band circularly polarized antenna for WLAN and WiMAX applications based on characteristic mode theory

Abstract A multi-band circularly polarized antenna is proposed for WLAN (2.4/5.3/5.8 GHz) and WiMAX (3.5 GHz) applications. The proposed antenna is constructed of a radiation patch and a reflecting metal ground. Characteristic mode theory is utilized to analyze the modes of the patch and based on these results the antenna is optimized. The −10 dB impedance bandwidths of the proposed antenna are 53.53% (2.4–4.15 GHz) and 47.28% (5.25–8.5 GHz), respectively. The antenna radiates left-handed circular polarization in the lower band and right-handed circular polarization in the upper band. A maximum gain of 10 dBic is achieved for the proposed antenna.

Ka-band diplexer design based on half-mode groove gap waveguide

Ka-band diplexer design based on half-mode groove gap waveguide

Dual-Wideband Antenna with Dual Polarization and Enhanced Front-to-Back Ratio for High-Speed Communication Applications

Dual-Wideband Antenna with Dual Polarization and Enhanced Front-to-Back Ratio for High-Speed Communication Applications

Response of anchor investors to pre-IPO earnings management: evidence from an emerging market

PurposeThis study aims to examine the reaction of anchor investors (AIs) to pre-IPO earnings management (EM). The authors use the unique detailed bid data from the Indian anchor experiment. The authors also study the reputed AIs’ EM detection ability and pricing behavior in response to pre-IPO EM.Design/methodology/approachThe authors use unique AI bid data for 169 Indian IPO firms. Utilizing the logistic regression and Tobit regression models with industry and year-fixed effects, the authors examine the relationship between various measures of AI participation and proxies of short-term and long-term discretionary accruals.FindingsThe authors document that pre-IPO EM is positively associated with the likelihood of anchor backing but negatively related to the likelihood of reputed anchor backing. The findings indicate that AIs are misled by pre-IPO EM, but reputed AIs are not. The authors also observe that reputed AIs, compared to the non-reputed, pay less than the upper band with increasing EM. The findings are robust to using various AI measures and EM proxies.Practical implicationsThe findings have significant implications for regulators in the implementation of AI concept in non-anchor markets and better implementation of policies in existing anchor settings. Findings can also be relevant for non-institutional investors in the IPO domain.Originality/valueThis is one of the few studies on institutional investors' IPO bidding behavior in response to pre-IPO EM. However, this is the first study to analyze AIs' IPO bidding behavior in response to pre-IPO EM.

Pattern Similarity and Gain Enhancement of Dual-Band Antenna Using an ENZ Metamaterial

A dual-band antenna with pattern similarity using the energy-squeezing mechanism of an epsilon-near-zero (ENZ) metamaterial is designed, and experimental results are presented with simulated data. To achieve high gain and pattern similarity, a waveguide-based ENZ metamaterial property is adopted in a planar microstrip form at the upper band. The designed dual-band antenna is resonating at 4.3 GHz and 9.8 GHz frequencies with the desired radiation pattern. A metamaterial unit cell with ENZ characteristics at 9.8 GHz is designed to improve the antenna’s performance. The permittivity and permeability of the unit cell are characterized using the Nicolson–Ross–Weir method. By adding a square ring structure, the antenna geometry exhibits ENZ characteristics. Using the ENZ material’s energy-squeezing mechanism, a 12-dB gain improvement is achieved in the upper band without affecting the lower band radiation characteristics without increasing the complexity. It can be used in C- and X-band applications, such as mobile, military, defense, and radar communication. The dual-band antenna with ENZ material is fabricated, and the measured results show a good match with the simulated results. The proposed antenna size at 4.3 GHz is 0.58λ × 0.58λ × 0.02λ.

Analysis and Prediction of Bollinger Bands to Predict Stock Prices in Determining Investment Strategies

It is critical for stock investors to be able to forecast future stock values in order to determine potential gains or losses. A technical analysis approach can be used to anticipate stock prices in the realm of stock investment. A technical analysis approach was used to construct the Bollinger bands detecting application system. Technical analysis is a means of observing price variations over a specific time period by employing historical data and indicators. The goal of this research is to predict Bollinger bands and define the circumstances for buying and selling stocks in technical analysis. The object of this study is the closing price of BBRI.JK, BBCA.JK and BMRI.JK during 2022. Data is analyzed using Bollinger Bands and decision to buy the right stock is when the actual price of the stock intersects with the lower band because at that time the stock price is increasing, while the decision to sell the right is when the actual price of the stock intersects with the upper band because at that time the stock price will decrease. In addition, the results of the Bollinger bands prediction for n + 1 from the last day of the sample, December 30, are respectively the upper and lower Bollinger bands on January 2, 2023, which are 5.012,948 and 4.775,052 for BBRI.JK shares, 8.755,919 and 8.446,581 for BBCA.JK shares, and 5.321,991 and 4.764,259 for BMRI.JK shares.

CRLH‐TL‐loaded metamaterial antenna with frequency band and polarization reconfigurability

SummaryIn this communication, an asymmetric co‐planar waveguide (ACPW)–fed composite right–left‐handed transmission line (CRLH‐TL)–based frequency band and polarization reconfigurable antenna (RA) is presented. The reconfigurability is achieved by using a PIN diode. When the diode is in OFF state, meander line works as part of ground. Hence, the antenna is like a circular patch antenna working at 5.15 GHz. In the ON state, the antenna works as a CRLH‐TL‐based antenna with an additional lower band resonating at 2.45 GHz. The antenna also has circular polarization (CP) property. The lower 2.4 GHz band is covering for IEEE 802.11 b/g/n/ax/be applications, whereas the higher band is covering the WiFi bands of IEEE 802.11a/h/n/ac/ax/be applications with CP radiation (upper band). This antenna is effective in a scattering environment such as in urban areas and indoor communication.

Design and Analysis of a Low-Profile Dual-Band Circularly Polarized Monopole Antenna Based on Characteristic Mode Analysis

This paper presents the design of a simple dual-band circularly polarized monopole antenna using characteristic mode analysis. First, a dual-band elliptically polarized “L”-shaped monopole antenna with a partial ground is designed; then, a rectangular stub and a parasitic structure on the ground plane are implemented to achieve dual-band CP operation. To enhance impedance bandwidth and generate circular polarization in the upper band, the rectangular stub is attached to the “L”-shaped strip. The parasitic structure is employed for simultaneous dual-band CP radiation. Characteristic mode analysis is undertaken to predict the performance of the antenna before excitation. The modal analysis which is undertaken before excitation shows the natural modes that can be excited by the antenna structure to generate a dual-band CP response. The analysis gives approximate bandwidths that can be achieved by the antenna even before excitation. The overall dimension of the antenna is 0.379 λ 0 × 0.379 λ 0 × 0.015 λ 0 , where λ 0 is the corresponding free-space wavelength at 5.7 GHz. The measured -10 dB impedance bandwidth (ZBW) is realized to be 75.9% (4.5 GHz–10 GHz). The measured 3 dB axial ratio bandwidths (ARBW) at the lower and upper bands are 6% (5.6 GHz–5.95 GHz) and 28% (6.65 GHz–8.82 GHz), respectively. The proposed antenna features a simple and compact structure for Wi-Fi, WLAN, WiMAX, and C band applications.