Arc-shaped Strip Research Articles

Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.

An integrated hydrothermal process of bamboo flattening, densification and drying: Mechanical properties and strengthening mechanisms

Bamboo is widely recognized as an engineering material with great potential. Conventional rectangular bamboo strip lumber has low utilization rate from milling arc-shaped strips flat and variable strength properties from natural bamboo’s hierarchical tissue structure. In this work an energy-efficient hydrothermal compression process to flatten and densify arc-shaped bamboo is presented. The green (70 % moisture content) bamboo strips were hot compressed in the radial direction at 3.0 MPa pressure, and at 170 °C or 190 °C heat for 20 min. After compression, arcs became rectangular with low (<10 %) moisture content and significant enhancement of mechanical properties. The bending strength, bending modulus, compressive strength, and shear strength of bamboo were improved by 128.1 %, 91.6 %, 58.2 %, and 74.5 %, respectively. Increased density and fiber bundle fraction, altered failure modes and chemical characteristics, increased cellulose crystallinity and crystalline size, and increased nanoscale mechanical properties were observed as contributing factors to tissue strength enhancement. The process could potentially eliminate the conventional strip milling and lengthy drying processes currently used to produce laminate bamboo lumber.

Wideband Circularly Polarized Microstrip-Slot Antenna with Parasitic Ground Planes

In this study, a new stacked microstrip slot antenna (MSA) with wideband circular polarization (CP) characteristics is proposed. The antenna consists of a square-loop feed configuration, four parasitic square patches, four parasitic vertical planes, and a square ground plane etched with four parasitic square slots. The corner-cut square-loop can excite a stable 270° phase difference by loading an arc-shaped strip into the square-loop. Square-patches, vertical planes, and square slots as parasitic elements are placed together at the side of the square-loop to stimulate two CP resonant points. Simulation and measurement are performed on the designed antenna prototype to demonstrate the design’s rationality. The measured results depict that the measured impedance bandwidth (IBW) for |S11| &lt; −10 dB is 36.4% (4.65 to 6.70 GHz) and the measured axial ratio bandwidth (ARBW) for AR &lt; 3 dB is 25.1% (5.01 to 6.45 GHz). Compared with other reported stacked CP antennas, the proposed antenna has significant advantages in CP bandwidth, which could occupy the wireless local area network ITS (5.8 GHz), (5.725–5.85 GHz), and WIFI (5.85–5.925 GHz) bands.

A compact broadband microstrip slot circularly polarized antenna using parasitic elements

ABSTRACT A new broadband circularly polarized (CP) microstrip slot antenna (MSA) is proposed in this study. The proposed CP MSA is comprised of a square-loop feed configuration, four rectangular patches as parasitic patches, and a square ground plane etched with four L-shaped slots as parasitic slots. The square-loop feed configuration, which can stimulate a 270° phase difference, comprises an arc-shaped strip and a square-loop. Rectangular patches and L-shaped slots as parasitic elements are together arranged and etched at the side of the square-loop feed configuration to excite multiple CP resonant modes using a capacitively coupled feeding technology. A prototype of the proposed antenna was simulated, manufactured, and measured in this study. The measured results depict that the CP MSA features a wide impedance bandwidth of 4.36–5.36 GHz (20.6%) for|S11| < −10 dB and broad axial ratio bandwidth (ARBW) of 4.53–5.30 GHz (15.7%) for AR < 3 dB. Thus, the proposed CP MSA would be an outstanding candidate in wireless communication systems.

A Compact Wideband Circularly Polarized Microstrip Slot Antenna with Parasitic Elements

A compact wideband circularly polarized (CP) microstrip slot antenna (MSA) with parasitic elements is designed in this letter. The CP MSA comprises a square-loop sequential-phase (SP) feeding configuration, four rotated rectangular patches, and four L-shaped slots embedded in the ground plane. The square-loop SP feeding structure comprises a square loop and an arc-shaped strip, which could provide a 270° phase difference. Four rotated rectangular patches are placed at the edge of the square-loop feeding configuration using a capacitively tightly coupled feeding method to stimulate the CP resonant mode. After selecting these elements and tuning proper dimensions, the broad operating bandwidths of 4.38–5.25 GHz (18%) for |S11| &lt;–10 dB and 4.65–5.31 GHz (13.2%) for AR &lt;3 dB could be realized. Hence, the designed CP MSA has a potential application value in wireless communication.

A broadband circularly polarized stacked microstrip patch antenna with parasitic elements

In this article, a wideband circularly polarized stacked microstrip patch antenna (CP SMPA) with continuous phase feed characteristics is presented. The designed antenna consists of a square-loop feeding structure as driven element, four rectangular-patches and four rotated square-patches as parasitic elements. First, a square-loop with arc-shaped strip is designed to obtain 90° phase difference. Second, four rectangular-patches are placed next to the square-loop for generating a CP resonant mode through a capacitive coupling method. Third, four rotated square-patches are arranged at the top of the rectangular-patches to excite an additional CP resonant mode. Eventually, the designed CP SMPA features a wide −10-dB impedance bandwidth (IBW) of 32% (5.93 GHz, 4.98–6.88 GHz), and a broad 3-dB axial ratio bandwidth of 22.8% (6.15 GHz, 5.45–6.85 GHz).

Quad-polarization reconfigurable holographic artificial impedance surface based on liquid crystal at terahertz band

A novel quad-polarization reconfigurable holographic artificial impedance surface that exploits the tunable dielectric permittivity of nematic liquid crystal is proposed. The arc-shaped strip is introduced and serves as the fundamental element, and further combined with holographic modulation, electromagnetic radiation at the terahertz band is realized. By partitioning the circular surface into several sectors, studies show that just two impedance values for each sector are enough to reconfigure among different polarizations. The presented demonstrator has a radius of 4.3λ 0, where λ 0 is the wavelength in free space at 1.25 THz, and is excited by a monopole. It can be dynamically reconfigured among vertical linear polarization, horizontal linear polarization, right-hand circular polarization, and left-hand circular polarization at the boresight.

Dual-Band Circularly Polarized Millimeter-Wave Antenna for 5G-WiGig Applications

In this paper, a dual band dual circularly polarized microstrip antenna for 28/60 GHz applications is presented. This antenna is designed to be used in hand-held devices for both 5G and WiGig applications simultaneously. The circular polarization in this case represents an important advantage to avoid polarization mismatch at different orientations. The proposed antenna consists of two parts: an annular ring around a circular patch with slot perturbations in both of them. The two parts of the proposed antenna are resonant at different frequencies. The inner circular patch is designed to be resonant around the 60 GHz band while the annular ring is designed to be resonant around the 28 GHz band. These two parts are simultaneously excited by an arc-shaped strip. Each part of this antenna structure operates as a single band circularly polarized radiator. The circular polarization is obtained by exciting orthogonal modes in each part of this antenna configuration with equal amplitudes and 90° phase shift. These orthogonal modes are obtained by introducing perturbations in both the inner circular disk and the outer annular ring. These perturbations are shifted by 45° from the location of the feeding arc. However, these perturbations affect the matching properties of designed antenna. Thus, a meander line stub is connected to the annular ring to adjust the matching of the designed antenna. The characteristics of the proposed antenna are designed and simulated by using full-wave EM simulator CST Microwave Studio and High Frequency Structural Simulator (HFSS).

Differentially Inserted-Fed Compact Dual-Band Circularly Polarized Dielectric Resonator Antenna

In this letter, a differentially inserted-fed compact dual-band circularly polarized dielectric resonator antenna (DRA) is proposed. To realize a compact design, the inserted differential feeding structure composed of a pair of arc-shaped strips connecting with coaxial probes plays dual roles. It not only excites the fundamental mode HEM111 of the DRA, but also brings an additional resonant mode to form the second band. Besides, the lower and upper bands of the DRA are independently controlled by the DR and the strips, facilitating the design process of the dual-band DRA. For demonstration, a prototype is designed, fabricated, and measured. Measured results show that the proposed DRA with the profile of 0.34 $\lambda _{g}$ achieves impedance bandwidth (| S dd11|<−10 dB) of 30.4% and 18.5% and 3 dB axial-ratio bandwidth of 8.06% and 6.38% with peak gain of 6.9 and 7.3 dBic for the lower and upper bands, respectively. Good agreement is observed between the simulated and measured results.

Arc-Shaped Strip in Radiating Patch with Rectangular Stubbed Ground Plane for Wideband Applications

A printed planar antenna having compact dimensions of 0.35×0.25λ, mm2 and fed by a microstrip line for wideband applications is presented. The proposed antenna consists of a radiating patch, a new arc-shaped strip, microstrip feed line, and a rectangular stub loaded ground plane. Furthermore, the ground plane of the fundamental radiator is modified to improve the voltage standing wave ratio (VSWR) bandwidth. A rectangular stub is added inside the ground plane to provide the bandwidth to suit the modern automotive requirements. We have analyzed the proposed antenna in terms of VSWR, reflection loss, gain, radiation pattern, and the housing effect. The measured results indicate that the antenna achieves a wide useable fractional bandwidth ratio of 129% at VSWR ≤ 2, ranging from 4.8 to 21.7 GHz. A measured bandwidth of 119% at VSWR ≤ 1.5 (5.5–20.9 GHz) is obtained. Stable quasi-omnidirectional radiation patterns with an acceptable gain of 4.87 dBi are achieved.

Low-RCS Reflectarray With Phase Controllable Absorptive Frequency-Selective Reflector

This paper presents a methodology to control the reflection phase response from a 3-D bandstop structure backed with an absorbing material. An absorptive frequency-selective reflection structure using the cascaded arc-shaped strip resonators and absorbers is utilized to obtain an absorption–reflection–absorption response. The reflection phase response of the structure within the reflection band is then flexibly controlled by top-loaded metallic patches with variable size. An application of this methodology is demonstrated by designing a high-gain and low-radar cross section (RCS) reflectarray. The in-band phase profile of the reflecting surface is constructively designed to collimate the beam in the far field. Meanwhile, the out-of-band scattering from the planar reflector is significantly reduced. Compared with a conventional reflectarray, the radiation performance of the proposed antenna is maintained with an aperture efficiency of 50.1% and directivity of 23.5 dBi. Significant RCS reduction has been achieved with a fractional bandwidth of 76.9% and 17.1% for the lower and upper bands with reduction levels of 10 and 8 dB, respectively.

Miniaturized circularly polarized patch antenna using coupled shorting strip and capacitive probe feed

This paper proposes a single-feed miniaturized circularly polarized (CP) patch antenna aimed to cover Chinese BeiDou navigation satellite system (BDS) B3 band (1268.52 ± 10.23 MHz). Four unbalanced circular patches as perturbation elements are loaded onto corners of a square patch radiator to ensure CP property. To simultaneously realize miniature size and adequate CP bandwidth, each circular patch is coupled to an L-shaped shorting strip consisting of a horizontal arc-shaped strip connected to the ground plane through a vertical shorting pin. In addition, a capacitive probe feed fulfilled by embedding an annular gap is used to compensate large probe inductance due to thick substrate, and therefore good impedance matching can be obtained. The antenna occupies an overall size of λ0/8 × λ0/8 × λ0/13.6, where λ0 denotes the free space wavelength at 1268 MHz. Experimental results show that it achieves a 10-dB return loss impedance bandwidth of 75 MHz (1237–1312 MHz) and a 3-dB axial ratio (AR) bandwidth of 31 MHz (1253–1284 MHz). The measured 3-dB AR beamwidth and CP gain are above 170° and 4.0 dBic, respectively, across the entire BDS B3 band.

A Low-Profile Omnidirectional Circularly Polarized Antenna Using Planar Sector-Shaped Endfire Elements

A single-layer circularly polarized (CP) antenna with omnidirectional radiation in the azimuth plane has been designed and evaluated. The concept is the combination of multiple identical endfire CP antenna elements in a circular array configuration. The design of each element is based on the superposition of two closely spaced complementary current sources, which are, respectively, realized by a sectorial parallel-plate cavity and arc-shaped strip arms. A meandered double-sided parallel strip line is introduced to adjust the phase relationship between two orthogonal linear polarized components. All antenna elements can be simultaneously excited by adopting a single coaxial probe in the center of the overall structure. Take 5.8-GHz Industrial Scientific Medical (ISM) band applications (5.725–5.875 GHz), for example, a prototype with a diameter of $0.62\lambda _{0}$ and a low profile of $0.029\lambda _{0}$ was fabricated. Experimental results show that the designed antenna has a usable bandwidth from 5.68 to 5.91 GHz (the common overlapped bandwidth limited by the −10 dB $\vert S_{11}\vert $ and the 3-dB axial ratio). Within the operation band, good omnidirectivity and a wide coverage can be obtained.

Optimization of Planar Monopole Wideband Antenna for Wireless Communication System

In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is compatible with a good number of wireless standards, including UWB band, Wimax 5.4 GHz band, MVDDS (12.2–12.7GHz), and close range radar and satellite communication in the X-band (8-12GHz), and Ku band (12-18GHz).

Dual-Band Dual Circularly Polarized Microstrip Antenna With Two Eccentric Rings and an Arc-Shaped Conducting Strip

In this letter, a novel low-profile dual-band and dual circularly polarized (CP) microstrip antenna is proposed. The antenna consists of two circular eccentric rings (CECRs) with different sizes. The two eccentric rings each work as a single-band circular polarization radiator and are simultaneously excited by an arc-shaped strip. A lumped equivalent circuit model is developed to analyze the operation mechanism of the antenna. In order to simplify the design procedure, empirical formulas are derived based on the physical parameters of the antenna. The proposed structure has been examined by both simulation and experiment, and both results agree very well.

Flexible Efficient Quasi-Yagi Printed Uniplanar Antenna

A flexible quasi-Yagi printed antenna that is a compact, efficient directive radiator is demonstrated. The simple uniplanar design incorporates an arc-shaped strip, which serves as a near-field resonant parasitic (NFRP) element, and a coplanar-waveguide (CPW)-fed semiloop antenna. The simulated and experimental results that are in good agreement confirm the forward endfire nature of the antenna. The total electrical size is only $0.17 \lambda_{0} \times 0.43{\lambda }_{0}$ , while having a high radiation efficiency to achieve a 5.76 dBi realized gain. A backward endfire version illustrates the radiation principles of the design. By mounting the uniplanar antenna conformally on a cylindrical structure, it is demonstrated numerically and experimentally that its radiation performance characteristics are maintained, confirming that only minor effects are introduced under bending conditions.

Circularly polarized square slot microstrip antenna for RFID applications

In this paper, a novel circularly polarized square slot microstrip antenna is proposed for radio frequency identification (RFID) applications. The circular polarization is achieved by incorporating an arc-shaped strip in the square slot antenna. This antenna is fed by deformed bent feeding line to achieve a broad bandwidth (BW). The key parameters of the antenna are used for parametric study to understand the influence on the antenna performance. To validate simulation results of the design, a prototype is fabricated on the commercially available FR4 material. Measured results show a good agreement with the simulated results. It is found that the antenna shows an impedance BW of 170 MHz (844–1014 MHz) and axial-ratio BW of 170 MHz (834–1004 MHz), which shows that the proposed antenna is a good candidate to be used as a RFID antenna.

Compact arc‐shaped antenna with binomial curved conductor‐backed plane for multiband wireless applications

This study proposes a novel design of compact printed multiband monopole antenna with binomial curved conductor-backed plane which generates five wide resonant frequency bands for |S 11| ≤ −10 dB to cover 2.4/5.2/5.8 GHz wireless local area network, 2.5/3.5/5.5 GHz worldwide interoperability for microwave access and ultra-wideband applications simultaneously. The radiating elements of the monopole are composed of multiple arc-shaped strips. The radius of each arc-shaped strip varies proportionally to the arithmetic progression sequence. The proposed multiband antenna is studied with different shapes of conductor-backed plane through the variation in order N of binomial curve equation. The overall dimension of the proposed multiband antenna is 32 × 25 × 0.8 mm3. The prototypes of the proposed multiband antenna are fabricated and tested. The radiation mechanism of the proposed multiband antenna is explained using simulated current distributions. Simulated and experimental results obtained for these antennas show that they exhibit good radiation behaviour within the operational frequency bands.

A Novel Monopole Antenna with Two Arc-Shaped Strips for WLAN/WiMAX Application

In this paper, a novel monopole antenna for WLAN/WiMAX application is presented. The proposed antenna consists of two arc-shaped strips, a vertical strip, and a slot in the ground plane. In this study, a prototype of the proposed triple-band antenna was designed, fabricated, and tested. The quantitative and experimental results demonstrate that the proposed antenna satisfy the -10 dB impedance bandwidth requirement of 440 MHz for 2.4/2.5 GHz bands (from 2.26 to 2.70 GHz), 970 MHz for 3.5 GHz bands (from 3.27 to 4.24 GHz), and 870 MHz for the GHz bands (from 5.08 to 5.95 GHz), while simultaneously covering the WLAN and WiMAX bands. In addition, the presented triple-band antenna has an omnidirectional radiation pattern at all three frequency bands with an antenna gain of 4.45 dBi for the lowest band, 2.04 dBi for the middle band, and 3.98 dBi for the highest band.

Design of a compact tuning fork-shaped notched ultrawideband antenna for wireless communication application.

A new compact planar notched ultrawideband (UWB) antenna is designed for wireless communication application. The proposed antenna has a compact size of 0.182λ × 0.228λ × 0.018λ where λ is the wavelength of the lowest operating frequency. The antenna is comprised of rectangular radiating patch, ground plane, and an arc-shaped strip in between radiating patch and feed line. By introducing a new Tuning Fork-shaped notch in the radiating plane, a stopband is obtained. The antenna is tested and measured. The measured result indicated that fabricated antenna has achieved a wide bandwidth of 4.33–13.8 GHz (at −10 dB return loss) with a rejection frequency band of 5.28–6.97 GHz (WiMAX, WLAN, and C-band). The effects of the parameters of the antenna are discussed. The experiment results demonstrate that the proposed antenna can well meet the requirement for the UWB communication in spite of its compactness and small size.