Compact Line Research Articles

Inline-delay Fourier transform imaging spectrometer for mid-IR ultrashort pulses

An inline-delay Fourier transform imaging spectrometer (iFTIS) is used to measure spatiospectral coupling in a mid-infrared (mid-IR) optical parametric amplifier (OPA). The method employs a compact inline delay line using a birefringent wedge pair and a microbolometer array as an imaging sensor, providing continuous spectral coverage from ∼0.4 to 4.5 µm in a single device. We find a spatial chirp that depends systematically on the OPA wavelength setting in the 3-4 µm range and also identify spatiospectral couplings beyond spatial chirp, highlighting the importance of advanced metrological techniques for this spectral region. Furthermore, we investigate the effect of depletion on the 2 µm pump beam and observe a complex spatiospectral reshaping. Our work opens the door to new applications of iFTIS to mid-IR laser science.

Barely alternating real almost chains and extension operators for compact lines

Assume MA(κ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {MA}(\\kappa )$$\\end{document}. We show that for every real chain of size κ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\kappa $$\\end{document} in the quotient Boolean algebra P(ω)/fin\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P(\\omega )/fin$$\\end{document} we can find an almost chain of representatives such that every n∈ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n\\in \\omega $$\\end{document} oscillates at most three times along the almost chain. This is used to show that for every countable discrete extension of a separable compact line K of weight κ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\kappa $$\\end{document} there exists an extension operator E:C(K)⟶C(L)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E:C(K)\\longrightarrow C(L)$$\\end{document} of norm at most three.

Simulation and measurement of electromagnetic wave propagations along a wearable e-textile metasurface transmission line

This study introduces a compact wearable metasurface transmission line operating at 2.45 GHz, utilizing spoof surface plasmon polariton (SSPP). The design incorporates a periodic arrangement of hook unit cells and a tapering structure to enhance coupling efficiency between the microstrip feed line and the metasurface transmission line. For its implementation, a dielectric substrate composed entirely of cotton denim jeans is employed, along with e-textile conductive traces and a ground plane. Electromagnetic wave propagation along the transmission line is simulated, and the primary wave mode and associated propagation characteristics are analyzed. Both simulation and measurement results confirm the successful performance of the metasurface transmission line for on-body signal transmissions.

Fabrication of SNAP structures by wire heating.

Surface Nanoscale Axial Photonics (SNAP) is a promising technological platform for creating novel optical devices such as compact high-Q tunable delay lines, signal processors, and optical comb generators. For this purpose, the development of simple and reliable methods for the accurate introduction of a nanometer-scale variation of the optical fiber surface is desirable. Here, we present an easy-to-implement technique for the introduction of nanoscale variations of the effective optical fiber radius by annealing with a heated metal wire. Using the proposed method, we introduce modifications of the fiber effective radius with accuracy better than 0.1 nm without post-processing, making the proposed approach the simplest alternative to the previously developed SNAP fabrication techniques.

Compact long differential transmission line with ground cavity in 65 nm CMOS

Compact long differential transmission line with ground cavity in 65 nm CMOS

Variety Breeding Studies on Hesperis isatidea (Boİss.) D.A. German & Al-Shehbaz

Hesperis isatidea (Boiss.) D.A.German & Al-Shehbaz, a member of the Brassicaceae family, represents a distinctive natural species characterized by its fragrant, conspicuous inflorescences, unique flower coloration, and distinct feather-like foliage. The Turkish name of the species is known as “Allı Gelin”. This species is native, exhibiting resilience to drought conditions and requiring minimal care. Cultivation studies on this species were carried out at Erzincan Horticulture Research Institute (Turkey) with project number 106G022 within the scope of TÜBİTAK (Turkish Scientific and Technological Research Council). The research aimed to determine optimal production techniques through generative and vegetative propagation methods. The project, initiated in 2013 and concluded in 2022, focused on developing a cultivar of the Allı Gelin plant using texel selection breeding techniques. Thirteen populations of Allı Gelin from institute's gene pool were utilized. Employing the Texel Selection method, four distinct lines were identified: compact, tightly spread compact, pyramid1and pyramid-2 shaped. Subsequent baby plant tests revealed stability in the tightly spread compact and pyramid-1 lines, leading to their selection for further breeding. Although breeding efforts continued on the compact line, the pyramid-2 line was discontinued due to an inability to attain the desired stability. The successfully tested variants, namely the pyramid-1 and tightly spread compact forms, have been earmarked as candidates for outdoor ornamental plant varieties. Registration procedures for these candidates are underway. These new varieties promise to enrich diversity within the ornamental plants sector, potentially enhancing competitiveness in foreign markets.

GMRT observations of hydroxyl megamaser (OHM) candidates from the ALFALFA survey

We present the results of our observations using the Giant Meterwave Radio Telescope (GMRT) to investigate the radio continuum and hydroxyl (OH) line emission of ten OH megamaser (OHM) candidates from the Arecibo Legacy Fast ALFA (ALFALFA) survey. Among these candidates, we identified two sources, AGC 115713 and AGC 249507, displaying compact OH line emission that is spatially associated with radio continuum emission. These characteristics are aligned with the typical properties of OHM galaxies. Furthermore, the infrared (IR) properties of these two galaxies are consistent with those of known OHM galaxies. Of the two sources, AGC 249507 has been confirmed through optical redshift, whereas AGC 115713 is aligned with a WISE color selection criterion in the literature, providing additional support for this source being an OHM galaxy, rather than a nearby H I galaxy. On the contrary, no significant spectral line emission was detected in the remaining eight OHM candidates using our full GMRT dataset. This suggests that the spectral line emission initially detected by the ALFALFA survey may have been significantly resolved in the high-resolution observations used in this work. Additionally, the absence of radio continuum emission in six candidates also distinguishes them from known OHM galaxies documented in the literature. These findings support the notion that OHM emission may be distributed on a subarcsecond scale, underscoring the utility of arcsecond-scale observations in confirming OHM candidates, particularly those lacking optical redshift data.

Architecture for sub-100 ms liquid crystal reconfigurable intelligent surface based on defected delay lines

AbstractReconfigurable intelligent surfaces, comprised of passive tunable elements, are emerging as an essential device for upcoming millimeter wave and terahertz wireless systems. A fundamental aspect of the device involves the tuning technology used to achieve reconfigurability. Among alternatives such as semiconductors and micro-electromechanical systems, liquid crystal offers advantages including cost- and power-effective large-panel scalability. In this context, conventional liquid crystal-based reconfigurable intelligent surface approaches face limitations in optimizing for bandwidth, response time and loss simultaneously, requiring trade-offs between them. Here we detail an architecture for a liquid crystal-based reconfigurable intelligent surface with compact defected delay lines that provide continuous, 360-degree tunability, enabling fast response time, wide bandwidth and low loss. A reconfigurable intelligent surface with a thin 4.6 μm liquid crystal layer is designed, fabricated, and characterized, exhibiting response times of 72 milliseconds, insertion losses below 7 dB, and a 6.8 GHz (10.9%) bandwidth at 62 GHz, all while utilizing a lossy glass substrate and gold as a conductor.

A Compact Wideband Branch Line Coupler for Lower 5G Applications

A Compact Wideband Branch Line Coupler for Lower 5G Applications

A multi-objective genetic algorithm approach applied to compact meander branch line couplers design for 5G-enabled IoT applications

A multi-objective genetic algorithm approach applied to compact meander branch line couplers design for 5G-enabled IoT applications

FAUST

Aims. Interstellar complex organic molecules (iCOMs) are species commonly found in the interstellar medium. They are believed to be crucial seed species for the build-up of chemical complexity in star forming regions as well as our own Solar System. Thus, understanding how their abundances evolve during the star formation process and whether it enriches the emerging planetary system is of paramount importance. Methods. We use data from the ALMA Large Program FAUST (Fifty AU STudy of the chemistry in the disk and envelope system of solar protostars) to study the compact line emission towards the [BHB2007] 11 proto-binary system (sources A and B), where a complex structure of filaments connecting the two sources with a larger circumbinary disk has previously been detected. More than 45 methyl formate (CH3OCHO) lines are clearly detected with upper energies in the [123, 366] K range, as well as 8 dimethyl ether transitions (CH3OCH3) in the [93, 191] K range, 1 ketene transition (H2CCO) and 4 formic acid transitions (t-HCOOH). We compute the abundance ratios with respect to CH3OH for CH3OCHO, CH3OCH3, H2CCO, t-HCOOH (as well as an upper limit for CH3CHO) through a radiative transfer analysis. We also report the upper limits on the column densities of nitrogen bearing iCOMs, N(C2H5CN) and N(C2H3CN). Results. The emission from the detected iCOMs and their precursors is compact and encompasses both protostars, which are separated by only 0.2″ (~28 au). The integrated intensities tend to align with the Southern filament, revealed by the high spatial resolution observations of the dust emission at 1.3 mm. A Position-Velocity and 2D analysis are performed on the strongest and uncontaminated CH3OCH3 transition and show three different spatial and velocity regions, two of them being close to 11B (Southern filament) and the third one near 11A. Conclusions. All our observations suggest that the detected methanol, as well as the other iCOMs, are generated by the shocked gas from the incoming filaments streaming towards [BHB2007] 11A and 11B, respectively, making this source one of the few where chemical enrichment of the gas caused by the streaming material is observed.

A Novel Compact Broadband Quasi-Twisted Branch Line Coupler Based on a Double-Layered Microstrip Line.

A novel quasi-twisted miniaturized wideband branch line coupler (BLC) is proposed. The design is based on bisecting the conventional microstrip line BLC transversely and folding bisected sections on double-layered substrates with a common ground plane in between. The input and output terminals, each with a length of λg/4, and the pair of quarter-wavelength horizontal parallel arms are converted into a Z-shaped meandered microstrip line in the designed structure. Conversely, the pair of quarter-wavelength vertical arms are halved into two lines and transformed into a periodically loaded slow-wave structure. The bisected parts of the BLC are placed on the opposite side of the doubled-layer substrate and connected through four vias passing through the common ground plane. This technique enabled a compact BLC size of 6.4 × 18 mm2, which corresponds to a surface area miniaturization by ~50% as compared to the classical BLC size of 10 × 23 mm2 at 6 GHz. Moreover, the attained relative bandwidth is 73.9% (4.6-10 GHz) for S11, S33, S21, and the phase difference between outputs (∠S21 - ∠S41). However, if a coupling parameter (S41) of up to -7.5 dB is considered, then the relative bandwidth reduces to 53.9% (4.6-10 GHz) for port 1 as the input. Similarly, for port 3 as the input, the obtained bandwidth is 75.8% (4.5-10 GHz) for S33, S11, S43, and the phase difference between outputs (∠S43 - ∠S23). Likewise, this bandwidth reduces to 56% (4.5-8 GHz) when a coupling parameter (S23) of up to -7.5 dB is considered. In contrast, the relative bandwidth for the ordinary BLC is 41% at the same resonant frequency. The circuit is constructed on a double-layered low-cost FR4 substrate with a relative permittivity of 4.3 and a loss tangent of 0.025. An isolation of -13 dB was realized in both S13 and S31 demonstrating an excellent performance. The transmission coefficients between input/output ports S21, S41, S23, and S43 are between -3.1 dB to -3.5 dB at a frequency of 6 GHz. Finally, the proposed BLC provides phase differences between output ports of 90.5° and 94.8° at a frequency of 6 GHz when the input ports 1 and 3 are excited, respectively. The presented design offers the potential of being utilized as a unit cell for building a Butler matrix (BM) for sub-6 GHz 5G beamforming networks.

Study on the Mechanism Effect of Bending Loads on the Decay-like Degradation of Composite Insulator GFRP Core Rod

This paper investigates the deterioration of, and the abnormal temperature rise in, the GFRP core rod material of compact V-string composite insulators subjected to prolonged alternating flexural loading under wind-induced stresses. The axial stress on the GFRP (Glass Fiber Reinforced Plastic) core rod, resulting from transverse wind loads, is a focal point of examination. By establishing a stress model and damage model, the paper simulates and computes the evolution of damage in the outer arc material of composite insulator core rods subjected to alternating flexural loads. Additionally, a multi-factor coupled aging platform is set up, integrating humidity, heat, and mechanical stress, to simulate the crazing deterioration process of composite insulators under alternating flexural loads. Experimental results reveal that during 400,000 alternating load cycles, the core rod underwent stages of surface damage, damage increasing, fatigue embrittlement, matrix hydrolysis, and fiber fracture. Simultaneously, the silicone rubber sheath on the outer side of the composite insulator’s bending arc develops cracks over aging time, creating pathways for moisture ingress into the interface and core rod. The dielectric constant and dielectric loss factor of the aging region of the core rod increase to varying degrees compared to the non-aging part. Moreover, the degree of abnormal heating of the samples intensifies with the duration of aging experiments. These findings underscore the significance of understanding the aging and decay-like fracture process of compact line V-string composite insulators. They provide crucial insights for future research aimed at enhancing the material properties of composite insulator core rods.

Compact Broadband Substrate-Integrated Coaxial Line 2-D Beamforming Network and Its Multibeam Array Antenna Applications

Compact Broadband Substrate-Integrated Coaxial Line 2-D Beamforming Network and Its Multibeam Array Antenna Applications

A Compact Coupled line Microstrip Band Pass Filter for Wireless Receiver Applications

A Compact Coupled line Microstrip Band Pass Filter for Wireless Receiver Applications

Countable discrete extensions of compact lines

Countable discrete extensions of compact lines

Single-Conductor Spoof Surface Plasmon Polaritons Transmission Line With Bandpass Feature Based on Embedded Cross-Shaped Resonators

In this brief, cross-shaped resonators (CSRs) are integrated in spoof surface plasmon polaritons (SSPPs) unit, and a novel compact single-conductor SSPPs transmission line (TL) with bandpass feature is proposed. In this design, a unit structure based on classical SSPPs structure embedded with a CSR is proposed. To analyze the proposed unit structure, scattering parameters and ABCD-matrix theories are used. After the theoretical analysis, a SSPPs TL with bandpass filtering property is designed. The simulated passband is from 7.9 to 12.2 GHz with a relative bandwidth of 42%. A prototype is fabricated and measured. The measured results are in agreement well with the simulated ones. This proposed structure is attractive and useful for the design of high integrated SSPPs circuits.

Analysis and Design of Novel 180° Hybrid for U-Band Monolithic Subharmonic Mixer in 0.15-μm GaAs pHEMT Technology

In this brief, a novel reduced-size 1800 hybrid is presented to implement a U-band subharmonic mixer (SHM) via a 0.15-μm GaAs pHEMT process. The isolations between Σ-port and -port of the proposed 1800 hybrid are significantly enhanced by two structures: one is a compact multiconductor edge-coupled line balun with artificial transmission line and the other is an in-phase power divider composed of λLO/4 coupled line. As a proof-of-principle demonstration, a single balanced SHM with an antiparallel diode pair configuration is designed and fabricated, which exhibits a conversion gain of -12.25 dB 1 1.55 dB within the operating RF frequency of 40 to 60 GHz under 14 dBm LO pumping power. The improved isolations of LO-to-RF and 2LO-to-RF are 33 to 47 dB and 44 to 57 dB, respectively. The measured results surpass previously reported performance of SHMs.

Compact effective surface plasmon polariton transmission line with undiminished bandwidth and enhanced field confinement.

In this work, we propose a compact effective surface plasmon polariton (CESPP) transmission line (TL) based on a structural dispersion-induced surface plasmon polaritons (SPPs) mode, which can enhance confinement while ensuring that the working bandwidth is not reduced. The dispersion relation of the CESPPs proposed in this article indicates that the shallower the groove, the stronger the confinement. Furthermore, the CESPPs may facilitate longitudinal miniaturization, since the configuration of the unit cell is simple. The coupling effect between two CESPP TLs has been well studied, revealing that excellent cross talk suppression can be achieved. The measurement results exhibit strong agreement with full-wave simulations, suggesting that the proposed CESPP TL holds significant potential for valuable applications in modern high-speed circuits.

Improved compact growth habit of Viola × wittrockiana through Rhizobium rhizogenes transformation

Compactness is an important breeding goal in the improvement of garden pansy varieties (Viola × wittrockiana Gams.). The desired compact stature is primarily obtained through the use of chemical growth retardants. Recently, an alternative strategy for creating compact ornamentals was proposed based on transformation by wild type rhizogenic agrobacteria and the regeneration of transformed hairy roots. Here, we report on the successful transformation and creation of compact garden pansy lines. The most efficient hairy root induction was obtained by Rhizobium rhizogenes strain ATCC15834. Shoot regeneration from hairy roots was obtained using 3 mg L−1 2iP and 0.3 mg L−1 2,4-D. The presence of R. rhizogenes T-DNA genes was confirmed in the regenerated lines. These lines displayed a varying degrees of dwarfed growth. Most notably the shoot length was reduced up to 49%. Other phenotypic traits that were induced include reduced peduncle length and smaller, wrinkled flowers. Several of these Ri lines with promising compactness have been selected for further breeding towards compact garden pansy varieties that are less dependent on chemical growth regulation.Graphical abstract