Vertical Linear Polarization Research Articles

OPTIMASI BANDWIDTH MENGGUNAKAN STUB MATCHING IMPEDANSI PADA RANCANG BANGUN ANTENA MONOPOLE ULTRA-WIDEBAND

The microstrip monopole antenna design study was developed to support Ultra-Wideband (3.1GHz-10.6 GHz) wireless communication technology. This research aims to obtain a minimalist antenna prototype with the ability to operate in the UWB frequency region. Bandwidth optimization is carried out to increase data speed access capacity in wireless communications. The antenna design has two structures in the conductor layer of the RT DUROID 5880 type substrate material. The surface layer structure is a square patch with a transmission line and an impedance stub. For the bottom layer of the substrate, a structure forms the DGS technique. The simulation method is carried out on the antenna design to obtain parameters, such as bandwidth return loss -10dB is 1.29 (fractional) or 9700MHz (absolute) and bandwidth measurement results (absolute) (12,800 MHz-absolute), VSWR (1:2), input impedance at the 3.8GHz frequency (Zin=31.23Ω-j4.12Ω), and the 13.6GHz frequency (Zin=62.93Ω+j28.4Ω). For radiation polarization, the beam width is 116 degrees and the directional strength (Gain) value is 3.15dBi. The entire antenna has the performance characteristics of operating in the Ultra-Wideband spectrum at C-band, X-band and Ku-band frequencies. Omnidirectional polarization, vertical linear polarization, and low gain and minimalist support communication devices.

High-precision two-dimensional displacement metrology based on matrix metasurface.

A long-range, high-precision, and compact transverse displacement metrology is of crucial importance in both industries and scientific researches. However, it is a great challenge to measure arbitrary two-dimensional (2D) displacement with angstrom-level precision and hundred-micrometer range. Here, we demonstrated a prototype of high-precision 2D-displacement metrology with matrix metasurface. Light passing through the metasurface is diffracted into three beams in horizontal (H), vertical (V), and diagonal (D) linear polarization. 2D transverse displacement of the metasurface relative to the incident light beam is retrieved from the interferential optical powers arisen from coherent superposition between H-polarized and D-polarized beams or V-polarized and D-polarized beams. We experimentally demonstrate that arbitrary displacement in 2D plane can be determined with high precision down to 0.3 nm in a large range of 200 micrometers. Our work broadens the application scope of metasurface and paves the way for development of ultrasensitive optical 2D displacement metrology.

High-precision positioning of Hall probes for SCU magnetic field measurement

A planar superconducting undulator (SCU) prototype with the magnetic length of 4 m and the magnetic gap of 5 mm is being developed for Shanghai High Repetition rate XFEL and Extreme Light facility (SHINE) to generate vertical linear polarization FELs. The magnetic field measurement device based on Hall probes has been built for the SCU. Three Hall probes mounted on a sledge are used to measure the magnetic field in the undulator gap. The three-dimensional positioning system based on the Gaussian laser beam for the sledge and the Hall probes is presented in detail in this paper.

Low‐profile multi‐polarization and pattern reconfigurable antenna based on metasurface

AbstractIn this letter, a low‐profile metasurface (MS) antenna with multi‐polarization and pattern reconfigurability is presented. The antenna mainly consists of two parts, including a loop antenna fed by balun, and a MS antenna excited by the coupled aperture. When switching the PIN diode and rotating the MS, the multi‐polarization and pattern reconfigurable ability of the antenna is obtained. While the loop antenna is excited, a horizontally linear polarized (HLP) wave and omnidirectional pattern are obtained. Besides, when the MS is operated, due to the differential phase between the orthogonal surface impedance components, the antenna can be switched between vertical linear polarization (VLP), left‐hand circular polarization (LHCP), and right‐hand circular polarization (RHCP). Furthermore, the antenna could achieve a directional pattern. As the simulated and measured results shown, the proposed antenna has an overlapped impedance bandwidth (IMBW) of 24.7% for all polarization modes and a 3‐dB axial ratio (AR) bandwidth of 11.8% for L/RHCP modes. Moreover, the antenna owns a low profile of 0.06 λ (under the operating centre frequency).

Development of an undulator with adjustable horizontal gap and with electromagnet and permanent magnet for rapid polarization switching

An undulator composed of an electromagnet (EM) and a permanent magnet (PM) has been developed to switch rapidly the right- or left-circularly polarized radiation. The polarization switching is achieved using the rapid change of polarity of excitation currents in the EM, which provides a vertical field in a fixed gap. A horizontal field is generated with a PM; the field strength is adjusted on altering its horizontal gaps. In addition to circularly polarized radiation, the structure fulfills the needs of horizontal and vertical linear polarization. In this paper, we discuss the compact structure and show a design to provide soft X-rays for TPS. The design considerations for this magnet include the design concept, magnetic materials, mechanical and coil structure, all of which are discussed in this paper.

Self-temperature compensation approach for fiber specklegram magnetic field sensor based on polarization specklegram analysis

A self-temperature compensation method based on polarization specklegram analysis and magnetic birefringence effect of magnetic fluid (MF) is proposed for a fiber speckle sensor (FSS). The temperature compensation is achieved by measuring the variation difference of the two specklegrams with vertical linear polarization state. A fiber specklegram magnetic field sensor has been designed with this method and the magnetic-birefringence effect of MF. The measurement of magnetic field with high stability and good repeatability has been successfully achieved, which demonstrates the effectiveness of the proposed method. Due to the merits of low cost, ease of implement and system simplicity, the proposed method can promote the practical use of the FSS in long term monitoring.

Design and characterization of polarization reconfigurable heart shape monopole antenna for 2.4 GHz application

<span>This article represented a heart shape reconfigurable monopole antenna with polarization diversity. The proposed antenna is fed by a 50 Ω microstrip feed line that is printed on a flexible FR-4 (εr=4.4) substrate. The antenna comprises a ring-slot, a cross slot and four positive-intrinsic-negative (PIN) diodes that are soldered on ring slot. Four PIN diodes act as a switch and by controlling these PIN diodes effective current direction is changed hence four various states of polarization are achieved. Four states of polarization such as horizontal linear polarization (H-LP), vertical linear polarization (V-LP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) can be switched easily with the help of these PIN diodes and achieved an efficiency of more than 90%. Proposed antenna shows voltage standing wave ratio (VSWR)<2 at all working frequency and -10 dB reflection coefficients (RC) bandwidths (BW) (i.e., S11≤-10 dB) about 32.86% for linear polarization (LP) states while RHCP and LHCP states possess BW of about 31.61% and 31.67% respectively. It also shows axial ratio (AR) BW of 3.41% and 2.44% for RHCP and LHCP, respectively. Besides, the antenna has a well-suited omnidirectional pattern with a positive gain of all working frequency of interest where cross-polarization level is much lower than that of antenna gain.</span>

Analysis of waveguide polarizers using equivalent network and finite elements methods

Current research is dedicated to the development of new theoretical model for guide polarization converter with irises. New created model is derived based on the equivalent circuits and transmission line representations. Specific feature of the model consists in the possibility of account of irises thickness in the simulations by approximate single-mode method. Using equivalent lumped elements of the circuits we obtained general scattering matrices of the polarization transformer for fundamental modes of vertical and horizontal linear polarizations. Besides, numerical simulations and optimization of the device were carried out by finite elements method. Good agreement of obtained optimal sizes and polarization characteristics is observed. Provided by the polarizer phase difference between two orthogonal polarizations falls within range 90°±5° in the operating Ku-band. Calculated ellipticity coefficient is better than 1.5 dB. Developed model can be applied for designing of new waveguide polarization converters, filters and other waveguide components with irises.

Simultaneous Measurement of pH and Temperature with Phase-Shifted Long-Period Fiber Grating Inscribed on High-Birefringence Fiber by CO₂ Laser Pulses.

We propose an optical fiber grating sensor capable of simultaneously measuring pH and temperature based on a phase-shifted long-period fiber grating (PS-LPFG) inscribed on high-birefringence fiber (HBF). The PS-LPFG was fabricated on HBF with CO₂ laser pulses, and a phase shift π was induced by inserting a grating-free fiber region (GFFR) between two identical LPFGs with a grating period of ˜510 μm. The length of the GFFR was set as half of the grating period to induce a π phase shift. With the spectral characteristics of a π-PS-LPFG exhibiting two split attenuation bands, the PS-LPFG written on HBF, which is referred to as the HB-PS-LPFG, can create two polarization-dependent transmission spectra with dual-resonance dips at different wavelengths according to two orthogonal input polarization states, e.g., linear horizontal polarization (LHP) and linear vertical polarization (LVP). For simultaneous measurement of pH and temperature with the fabricated HB-PS-LPFG as a sensor head, the inter-resonance wavelength separation of the dual-resonance dips in each transmission spectrum obtained for an LHP or LVP input signal was exploited as a sensor indicator. By investigating the wavelength changes of the two sensor indicators, which were induced by pH and temperature variations, linear and independent spectral responses to both pH and temperature variations were experimentally confirmed in a pH range from 1 to 11 and a temperature range from 25 to 65 °C. Owing to the unique pH and temperature responses of the fabricated HB-PS-LPFG, ambient variations in pH and temperature could be simultaneously estimated from the measured wavelength changes and sensitivities of the two sensor indicators.

28 GHz dual‐layer substrate integrated waveguide slot array antenna combined with quad‐polarization

This article presents a compact slot array antenna combined with quad-polarization for mm-wave applications. A novel modified short-circuit termination with inclined slot is proposed in this paper and a dual-layer structure has been adopted to achieve miniaturization and also to design a circular polarization feeding network. Two linear polarization feeding networks are designed independently so that four polarization states can be realized. Four polarization states, namely vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), and right hand circular polarization (RHCP) can be switched by feeding corresponding ports. Judging from impedance matching and axial ratio (AR), the antenna exhibits wide bandwidth. The −10 dB impedance bandwidth and 3 dB AR bandwidth are better than 14.2% (26-30 GHz) with gain about 5-8 dBic for both LHCP and RHCP. The linear polarization states have |S11| < −10 dB and a gain of 5-7 dBi over 26.5-29.5 GHz (10.7%). The size of the slot array antenna is 65 × 65 × 1.156 mm and measured results are consistent with simulations.

Parallel‐to‐orthogonal polarisation‐state converter for dual‐mode Nd:YVO 4 microchip laser

Polarisation-state conversion from parallel linear polarisation to orthogonal linear polarisation was successfully demonstrated using a birefringence crystal for the two longitudinal oscillation modes of a dual-mode Nd:YVO4 microchip laser. The laser emitted two longitudinal oscillation modes simultaneously in the vertical linear polarisation state with a frequency difference of 101 GHz. In the experiment, it was shown that by using a 17-mm-long LiNbO3 birefringence crystal, it was possible to almost perfectly convert the polarisation state of the two oscillation modes by providing a π-rad difference in phase retardations between the two oscillation modes. The residual elliptic component was eliminated using a pair of waveplates.

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.

직교 입력 편광에 따른 위상 천이 장주기 격자의 pH 및 온도 응답에 관한 연구

In this paper, we demonstrated an optical fiber sensor based on a phase-shifted long-period fiber gratin g (PS-LPFG) that could realize simultaneous measurement of surrounding pH and temperature variations. The PS-LPFG composed of a grating-free fiber region (GFFR) in the middle of two identical LPFGs was fabricated on high-birefringence fiber (HBF) with CO₂ laser pulses. In addition, a π phase shift formed by setting the length of the GFFR as half of the grating period of an LPFG allows a transmission dip to split into two attenuation bands at two different resonance wavelengths. Since HBF can preserve a linear state of polarization (SOP) if the input SOP is aligned with one of its two principal axes (fast or slow axis), a PS-LPFG inscribed on HBF (HB-PS-LPFG) can create two different transmission spectra for two orthogonal input SOPs, i.e., linear horizontal polarization (LHP) and linear vertical polarization (LVP). To investigate pH and temperature responses of the fabricated HB-PS-LPFG, the dip wavelength separation bet ween two different attenuation bands was used as a sensor indicator for an LHP or LVP input SOP. Consequently, pH- and temperature-induced wavelength variations of the two sensor indicators showed linear and independent spectral responses to both pH and temperature variations in a pH range from 3 to 11 and a temperature range from 25 to 65 °C. With these unique pH or temperature responses of the two sensor indicators, the fabricated sensor could realize simultaneous measurement of pH and temperature.

Polarimetry of soil and vegetation in the visible II: Mueller matrix decompositions

In this paper Mueller polarimetry is applied to study some natural scatter scenes in visible: soil, sand, clay and moss. To obtain the anisotropic and depolarizing properties of the samples under study, the existing additive and multiplicative decompositions of experimental Mueller matrices were used.It is shown that all samples are characterized by anisotropic depolarization: the highest depolarization is observed for the input right and left circular polarizations, the smallest - for the input vertical and horizontal linear polarizations. The anisotropic properties of the samples under study are characterized by linear phase and amplitude anisotropy.

Simultaneous Measurement of Liquid Level and Temperature Using In-Fiber Grating-Based Mach-Zehnder Interferometer and Faraday Rotator Mirror.

Here we propose an optical fiber sensor capable of simultaneous measurement of liquid level and temperature by utilizing cascaded long-period fiber gratings (LPFGs) inscribed on high-birefringence fiber (HBF) and a Faraday rotator mirror (FRM). Due to the in-fiber Mach-Zehnder interference and birefringence of the HBF, these cascaded LPFGs have polarization-dependent discrete interference spectra, each of which is created within one of the two different attenuation bands obtained in the two orthogonal input polarization states, e.g., linear horizontal polarization (LHP) and linear vertical polarization (LVP). The minimum transmittance dip was selected as a sensor indicator for each interference spectrum obtained for LHP or LVP input signal. To monitor these indicator dips associated with LHP and LVP, referred to as the IDH and IDV, respectively, with one spectral scanning, an FRM was connected to the end of the cascaded LPFGs. Both the IDH and IDV spectrally shifted according to liquid-level or temperature changes and showed very linear responses to them with adjusted R₂ values greater than 0.997. The liquid-level sensitivities of the IDH and IDV were measured as approximately -37.29 and -121.08 pm/mm in a liquid-level range of 0 to 55 mm, respectively. The temperature sensitivities of the IDH and IDV were measured as ˜28.79 and ˜218.21 pm/°C in a temperature range of 30 to 60 °C, respectively. Owing to their linear and independent responses to liquid level and temperature, our sensor can perform temperature-independent liquid-level measurement using their pre-determined liquid-level and temperature sensitivities, even if both liquid level and temperature change simultaneously.

Wideband Frequency Agile and Polarization Reconfigurable Antenna for Wireless Applications

In this article, a polarization reconfigurable concentric circle microstrip antenna with simultaneous frequency agility has presented. The frequency agility and polarization reconfigurability have been controlled by open stub cascaded branch-line coupler (OSCBLC) feed network configuration. The −10 dB tunable impedance bandwidth of 2.0 GHz to 3.0 GHz (40%) is achieved by varying the capacitance of four varactor diodes from 4.15pF (0 V) to 0.84pF (7.5 V). These varactor diodes are fixed between the circular patch and ring. The polarization is reconfigured by directing the input RF through a single pole 4 throw (SP4 T) and routed to a single pole double throw (SPDT) switch in the feed network configuration. The right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) are realized in the antenna by exciting the feed ports with a time phase difference of ± 90°. Similarly, the vertical linear polarization (V-LP) and horizontal linear polarization (H-LP) are attained in the antenna by excited any one port through the feed network. The impedance bandwidth (1.5 GHz to 3.5 GHz) of OSCBLC feed network configuration is well-matched with the agile wide impedance bandwidth of the designed antenna. The proposed designed antenna shows good agreement between simulated and measurement results for polarization reconfigurability and frequency agility.

Bimode Foster’s Equivalent Circuit of Arbitrary Planar Periodic Structures and Its Application to Design Polarization Controller Devices

Foster's equivalent circuit for 2-D planar periodic structures (PPSs) that exhibit an arbitrary geometry is presented for first time in this article. The proposed four-port network shows an invariant circuit topology to the PPS geometry and is completely comprised of invariant-frequency lumped elements. The circuit is the simplest in terms of number of elements within the bimode bandwidth for a certain geometry, and its topology makes it possible both a standardized process to obtain the equivalent circuit of an arbitrary geometry and the use of the circuit theory to design a multitude of devices. To perform a validation, the equivalent circuit of two different PPSs (a rotated dipole and a defected slotted ring) has been obtained and analyzed in single-layer and multilayer configurations. The circuit is also used as a tool to develop elliptical to linear (or circular) polarization converters. One of the designs presented at 20 GHz (in transmission) converts an incident elliptical polarization of axial ratio 5 and tilted φ = 20° into a purely linear vertical polarization of XP <; - 30$ dB, with near-zero reflections and insertion loss better than 0.1 dB. The designed device is also manufactured and tested, and the measurements are in good agreement with simulations.

Investigation of C-Band SAR Polarimetry for Mapping a High-Tidal Coastal Environment in Northern Canada

Synthetic Aperture Radar (SAR) has been used in characterizing intertidal zones along northern Canadian coastlines. RADARSAT-2, with its full polarimetric information, has been considered for monitoring these vulnerable ecosystems and helping enhance the navigational safety of these waters. The RADARSAT Constellation Mission (RCM) will ensure data continuity with three identical SAR satellites orbiting together, providing superior revisit capabilities. The three satellites are equipped with multiple configurations, including single-polarization (HH, HV, VV), conventional (HH-HV, VV-VH, and HH-VV), hybrid (i.e., compact) dual polarization, and fully polarimetric (FP) modes. This study investigates the potential of the compact polarimetric (CP) mode for mapping an intertidal zone located at Tasiujaq village on the southwest shore of Ungava Bay, Quebec. Simulated RCM data were generated using FP RADARSAT-2 images collected over the study site in 2016. Commonly used tools for CP analysis include Raney m-delta classification and the hybrid dual polarizations RH-RV (where the transmitter is right-circular and the receivers are horizontal and vertical linear polarizations) and RR-RL (where the transmitter is right circular and the receivers are right-circular and left-circular polarizations). The potential of CP is compared with single, conventional dual-pol, and FP. The Freeman–Durden and Touzi discriminators are used for FP analysis. The random forest classifier is used as a classification approach due to its well-documented performance compared to other classifiers. The results suggest that the hybrid compact (RR-RL and RH-RV) dual polarizations provide encouraging separability capacities with overall accuracies of 61% and 60.7%, respectively, although they do not perform as well as conventional dual-pol HH-HV (64.4%). On the other hand, the CP polarimetric m-delta decomposition generated slightly less accurate classification results with an overall accuracy of approximately 62% compared to the FP Freeman–Durden (67.08%) and Touzi discriminators (71.1%).

XTIP - the world's first beamline dedicated to the synchrotron X-ray scanning tunneling microscopy technique.

In recent years, there have been numerous efforts worldwide to develop the synchrotron X-ray scanning tunneling microscopy (SX-STM) technique. Here, the inauguration of XTIP, the world's first beamline fully dedicated to SX-STM, is reported. The XTIP beamline is located at Sector 4 of the Advanced Photon Source at Argonne National Laboratory. It features an insertion device that can provide left- or right-circular as well as horizontal- and vertical-linear polarization. XTIP delivers monochromatic soft X-rays of between 400 and 1900 eV focused into an environmental enclosure that houses the endstation instrument. This article discusses the beamline system design and its performance.

편광상이 고리 기반 광섬유 다파장 필터의 입력 편광으로 제어되는 채널 간격 스위칭에 대한 연구

In this paper, we propose an optical fiber multiwavelength filter based on a polarization-diversified loop (PDL), whose channel spacings (CSs) can be controlled by its input state of polarization (SOP). The PDL-based filter consists of a polarization beam splitter, three half-wave plates (HWPs), a Faraday rotator (FR), and two polarization-maintaining fiber (PMF) segments with equal birefringence and different lengths. At proper orientation angle sets (θ<SUB>h1</SUB>, θ<SUB>h2</SUB>, θ<SUB>h3</SUB>) of the three HWPs, the proposed filter can have its polarization-dependent transmittance, offering the CS-switchable operation realized by switching between two orthogonal input SOPs of linear horizontal polarization (LHP) and linear vertical polarization (LVP). In particular, at a fixed input SOP, a half-period wavelength switching operation, i.e., an interleaving operation, can also be implemented by controlling only one HWP angle (θ<SUB>h1</SUB> or θ<SUB>h3</SUB>). Theoretical prediction was verified by experiments. For orthogonal input SOPs of LHP and LVP, the fabricated PDL-based filter could provide transmission spectra with CSs of ∼0.9 and ∼0.3nm or vice versa at appropriate sets of (θ<SUB>h1</SUB><SUB></SUB>, θ<SUB>h2</SUB>, θ<SUB>h3</SUB>), respectively, and each of the transmission spectra could be interleaved by adjusting only θ<SUB>h1</SUB> or θ<SUB>h3</SUB>.