Search

This communication presents a novel vertical polarized (VP) endfire phased array antenna (PAA) using heterogeneous beam elements (HBEs) for wide-angle scanning, where the HBE is a specially designed element with an inclined beam. First, the proposed low-profile and wideband endfire VP element is achieved by implementing an open-end cavity radiator with three slots. Additionally, by tilting the aperture of the VP element to realize gradient phase distribution, the HBE with an inclined beam is obtained, which is then used to form a VP HBE PAA. The desired array layout is achieved by adjusting the tilting angles of individual HBEs. Finally, a $1\times 4$ -element VP HBE PAA is designed, fabricated, and measured, exhibiting a 3-dB gain variation scanning range of ±72° across the entire 5G n258 band (24.25–27.5 GHz). Compared to the standard design, the VP HBE PAA provides an extended scanning range of ±12° while maintaining the same array size, with only a minimal decline of approximately 0.8 dBi in broadside realized gain. To the best of our knowledge, the proposed design achieves the widest scanning range compared to its predecessors.

Circularly polarized (CP) phased array antennas (PAAs) often face challenges in achieving wide element beams and axial ratio (AR) patterns simultaneously, thereby constraining their scanning ranges. To address this issue, this article introduces heterogeneous beam element (HBE) technology to the CP PAA design, proposing an offset segmented dielectric lens (OSDLs) beam tilting technology for implementing HBEs. By positioning the OSDL offset within the near-field region above one side of the element, the near-field region is partitioned into multiple segments with varying phase differences, achieving element beam tilting. The study provides a comprehensive analysis of the CP HBE PAA design, encompassing the CP element design with a wide spatial AR bandwidth and high isolation, as well as the principle and design guidelines of the OSDL beam tilting technology. Experimental results demonstrate a significant extension of the scanning range compared to the $4 \times 4$ -element CP standard PAA, with improvements ranging from 56° to 75° in the orthogonal plane and from 58° to 80° in the diagonal plane across the 17–20-GHz band while maintaining AR values below 3 dB. The effectiveness and robustness of the OSDL beam tilting technology underscore its potential as a universal HBE implementation approach.

This communication presents a novel compact wideband dual-polarized (DP) endfire antenna with a shared aperture. The design achieves a low-profile and wideband vertical-polarized (VP) element by utilizing an open-end cavity antenna with a U-slot and rectangular parasitic patch. A horizontal-polarized (HP) radiator is seamlessly integrated into the VP element by transforming the rectangular parasitic patch into a dipole, enabling structure reuse without affecting the VP mode. These designs enable the construction of a compact DP endfire antenna with a shared aperture while simultaneously enhancing performances, including impedance bandwidth, front-to-back ratio (FBR) level, polarization isolation, and cross-polarization. Moreover, a $1\times 4$ -element array with high gain is designed based on the proposed element. Prototypes are fabricated using low-temperature co-fired ceramics (LTCC) technology for antenna-in-package (AiP) applications. As the simulated and measured results demonstrate, the antennas achieve a wide overlapped DP impedance bandwidth of 24–30 GHz (22.2%) and a low profile of $0.12\lambda _{{0}}$ . Specifically, the VP FBR levels surpass 14 dB (element) and 16 dB (array), while the port isolations exceed 30 dB (element) and 25 dB (array). Overall, this design presents a promising solution for high-integration mmWave mobile systems.

This article presents a new design of an endfire phased array antenna (PAA) using heterogeneous beam elements (HBEs) for wide-angle scanning. The HBEs are specially designed elements with inclined and controllable beam directions, which incorporate a printed dipole and a rotary ground to achieve the desired beam inclination. Then, the PAAs are constructed based on the proposed HBE, and the array arrangement is realized by adjusting the beam-inclined angle of each element. As a result, the proposed HBE PAAs effectively maintain a stable effective aperture across various scanning angles and thus achieve a wide scanning range with a low gain variation. Prototypes of $1\times4$ and $1\times8$ -element HBE PAAs are designed, fabricated, and measured. The simulated and measured results reveal a significant improvement within the scanning range for the proposed HBE PAAs compared to their standard counterparts. The $1\times4$ and $1\times8$ -element HBE PAAs achieve impressive scanning ranges of $\ge \pm 70^{\circ }$ and $\ge \pm 80^{\circ }$ , respectively, within a wide impedance bandwidth of 24.25–29.5 GHz (19.8%), at the cost of a slight decline in normal-direction gain (< 1.2 dBi). This design offers a promising solution to enhance the performance of PAAs for mmWave mobile terminals.

A phased array antenna (PAA) incorporating a dielectric dome lens (DL) extends its scanning range but concurrently experiences a notable reduction in broadside gain due to the inherent diverging lens characteristics near the broadside. Instead of using a whole dielectric DL, this article proposes a dielectric top-truncated dome lens (TTDL) to address this issue. The approach mitigates broadside gain reduction by eliminating the dielectric DL’s inherent diverging characteristics near the broadside through truncation of its upper portion. The study elucidates the design fundamentals for the dielectric TTDL, encompassing an analysis of the truncation impact and the corresponding phase compensation strategy aimed at mitigating this truncation effect. Utilizing ray-tracing methods and full-wave simulations, this work comprehensively evaluates the performance disparity between the TTDL and conventional DL, revealing the effectiveness of the proposed approach. Additionally, the structural flexibility of the TTDL is discussed to facilitate a more compact architecture. Experimental validation of a TTDL antenna, incorporating a feed array and a compact dielectric TTDL, is presented. Results demonstrate that within the 26.5 to 29.5 GHz operating band, the compact TTDL effectively extends the scanning range from 60° to 80° while avoiding broadside gain reduction and maintaining a gain fluctuation within 5 dB.

This communication introduces an innovative distributed integrated antenna (DIA) architecture for millimeter-wave (mmWave) mobile terminals. The DIA discretizes the antenna into multiple components: basic structures and auxiliary structures, which are located on different parts of the mobile terminals, including chip, package, PCB, and shell. Meanwhile, the signal pathway between these components is achieved by the antenna’s internal electromagnetic coupling rather than a conductive connection, leading to lower radiation loss and larger availability in design space. This communication, moreover, presents several representative schemes of the DIA architecture and compares them with conventional architectures. In particular, a new scheme using the same basic structure is proposed to further reduce manufacturing costs and simplify the production cycle. To demonstrate this new scheme, three antenna examples using the same dipole on the package are designed. By combining different auxiliary structures on PCB/shell, varying radiation patterns, including beam steering, gain enhancement, and polarization conversion, are achieved. The simulated and measured results both show that all antennas can reach a wide impedance bandwidth of 24.25–29.5 GHz, with a high radiation efficiency exceeding 70%; therefore, the feasibility of the new scheme for DIA architecture is sufficiently verified.

Efficient separation and purification of xenon (Xe) from krypton (Kr) represent an industrially crucial but challenging process. While the adsorption-based separation of these atomic gases represents an energy-efficient process, achieving highly selective adsorbents remains a difficult task. Here, we demonstrate a supramolecular assembly of coordination polymers, termed as M(II)-dhbq (M = Mg, Mn, Co, and Zn; dhbq = 2,5-dihydroxy-1,4-benzoquinone), with high-density open metal sites (5.3 nm–3) and optimal pore size (5.5 Å), which are able to selectively capture Xe among other chemically inert gases including Kr, Ar, N2, and O2. Among M(II)-dhbq materials, Mn-dhbq exhibits the highest Xe uptake capacity of 3.1 mmol/g and a Xe/Kr selectivity of 11.2 at 298 K and 1.0 bar, outperforming many state-of-the-art adsorbents reported so far. Remarkably, the adsorption selectivity of Mn-dhbq for Xe/O2, Xe/N2, and Xe/Ar at ambient conditions reaches as high as 70.0, 139.3, and 64.0, respectively. Direct breakthrough experiments further confirm that all M(II)-dhbq materials can efficiently discriminate Xe atoms from other inert gases. It is revealed from the density functional theory calculations that the strong affinity between Xe and the coordination polymer is mainly attributed to the polarization by open metal sites.

A dual-polarized (DP) antenna with a conical radiation pattern and high gain characteristics is proposed. It is mainly comprised of a horizontally polarized (HP) array, a vertically polarized (VP) element, a fence, and a feeding network. In the HP direction, a rotatable stacked substrate-integrated waveguide (SIW)-to-coaxial-to-SIW transition (SCST) is meticulously designed to yield omnidirectional radiation with low gain variations and low transmission loss. As for the VP direction, two orthogonal substrates that are arranged above the VP radiating element act as a holder to fix the director, resulting in gain enhancement. Here, the VP element is placed in the center of the HP array to share the aperture for size reduction. Moreover, the top-hat-shaped metal fence collaborates with the large-size ground plane to yield dual conical beams with high gain in DP directions. From the measured results, the HP direction has exhibited desirable bandwidth of 11.4% (24.8–27.8 GHz) with a peak gain of 11.6 dBi, and the VP direction has demonstrated wider bandwidth of 13.7% (24.5–28.1 GHz) with a corresponding gain up to 8.1 dBi. Notably, low gain variations of ±0.65 and ±0.8 dBi are also realized for the HP and VP directions, respectively. Therefore, a DP antenna with high-gain conical beams and low gain variations can be obtained for the fifth-generation (5G) millimeter-wave (MMW) ceiling communications.

The effective removal of radioactive 99TcO4–anion from nuclear wastewater remains a very difficult unsolved problem. Functional adsorbent materials with high stability, anion-exchange capacity, excellent selectivity, and recyclability are much needed to solve this problem. In this work, we designed two stable cationic metal–organic frameworks (MOFs)—Zr-tcbp-Me and Zr-tcpp-Me—for possible use as adsorbent materials to remove 99TcO4–. Both compounds were synthesized by solvothermal reactions of the tetracarboxylate ligand with zirconium salt, followed by postsynthetic modification (N-methylation). The crystallinity of both zirconium-based MOFs can be well retained under harsh conditions, and they exhibit high adsorption capacity and selectivity toward ReO4–anion, a nonradioactive analogue of 99TcO4–. Zr-tcbp-Me and Zr-tcpp-Me demonstrate the highest framework stability toward acidity among all previously reported cationic MOFs that have been tested for perrhenate removal from wastewater.

Purification of propylene from the propyne (C3H4)/propylene (C3H6) mixture is a significant and challenging process in the chemical industry. Nowadays, the removal of propyne from propylene mainly relies on the energy-intensive hydrogenation catalyzed by noble metals. We herein report three gallate-based metal–organic frameworks, namely, M(II)-gallate (M = Ni, Mg, Co), which provide excellent performance in terms of removing propyne from the propyne/propylene mixture (1:99, v/v). The C3H4uptake capacities of Mg-, Co-, and Ni-gallate can reach 3.75, 3.21, and 2.65 mmol/g, while the C3H6uptake capacities are only 1.50, 1.49, and 0.9 mmol/g respectively, at ambient conditions. Particularly, the productivities of 99.9999% pure C3H6in Co-gallate and Mg-gallate were 1580 and 1420 mL/g, respectively, outperforming the state-of-the-art material USTA-200 (1400 mL/g). The adsorption mechanism was further investigated by using the first-principle dispersion-corrected density functional theory calculations, revealing that the excellent C3H4/C3H6separation ability of M-gallate originates from stronger supramolecular interactions and C–H···O interactions between the hydrogen atoms from C3H4and oxygen atoms from M-gallate frameworks. Besides, the M-gallate materials also show excellent regeneration ability. Thus, this work demonstrates that the family of M-gallate materials shows industrially promising porous materials for propylene purification by the adsorption process.

The separation of mixed C4olefins is a highly energy-intensive operation in the chemical industry due to the close boiling points of the unsaturated C4isomers. In particular, the separation of trans/cis-2-butene is among the most challenging separation processes for geometric isomers and is of prime importance to increase the added value of C4olefins. In this work, we report a series of isostructural gallate-based metal–organic frameworks (MOFs), namely, M-gallate (M = Ni, Mg, Co), featuring oval-shaped pores, that are ideally suitable for shape-selective separation of trans/cis-2-butene through their differentiation in minimum molecular cross-section size. Significantly, Mg-gallate displays a record high trans/cis-2-butene uptake selectivity of 3.19 at 298 K, 1.0 bar in single-component adsorption isotherms. These gallate-based MOFs not only exhibit the highest selectivity for trans/cis-2-butene separation but also accomplish a highly efficient separation of 1,3-butadiene, 1-butene, and iso-butene. DFT-D study shows that Mg-gallate interacts strongly with trans-2-butene and 1,3-butadiene along with short distances of C···H–O cooperative supramolecular interaction of 2.57–2.83 and 2.45–2.79 Å, respectively. In breakthrough experiments, Mg-gallate not only displays prominent separation performance for trans/cis-2-butene but also realizes the clean separation of a ternary mixture of 1,3-butadiene/1-butene/iso-butene and a binary mixture of 1-butene/iso-butene. This work indicates that M-gallate are industrially promising materials for adsorption separation of geometric isomers of C4hydrocarbons.

The simultaneous capture of trace propyne and propadiene from propylene is one of the important but energy demanding industrial processes because of their similar physicochemical properties as well as the ultralow concentration in the mixtures. Herein, a highly stable Ca-based MOF, constructed from an inexpensive precursor (CaCO3) and rigid squaric acid, is capable of preferentially capturing trace propyne and propadiene with record-high uptake capacities of 2.44 and 2.64 mmol/g at pressures as low as 5 mbar, respectively. Direct multicomponent breakthrough experiments confirm that Ca-based MOF exhibits an excellent performance for simultaneous removal of trace propyne and propadiene from propylene. DFT simulation and in situsingle-crystal X-ray diffraction of propadiene- and propyne-adsorbed Ca-based MOFs reveal that the strong affinity of the framework toward two species is ascribed to the multiple types of cooperative binding including π–π stacking and C–H···O interactions. The calcium squarate framework sets a new benchmark for adsorptive purification of propylene, showing great potential in the practical application.

Two ultramicroporous metal–organic frameworks, Zn(ox)0.5(trz) and Zn(ox)0.5(atrz) (ox = oxalate, trz = triazolate, and atrz = 3-aminotriazolate), have been synthesized and tested for the adsorptive separation of Xe and Kr. We demonstrate that the Xe/Kr adsorption selectivity relates to the pore size as well as the structure flexibility of the adsorbents.

The pore size of adsorbents plays a vital role in determining the overall separation performance of gas separation and purification by adsorption. In this work, the pore apertures of the coordination pillared layer (CPL) was systematically controlled by adjusting the length of pillared ligands. We used pyrazine, 4,4′-bipyridine, and 1,2-di(4-pyridyl)-ethylene with increased length to synthesize CPL-1 (L = pyrazine), CPL-2 (L = 4,4′-bipyridine), and CPL-5 [L = 1,2-di(4-pyridyl)-ethylene], respectively. The aperture size of these CPLs varies from 4 to 11 Å: CPL-1 (4 × 6 Å2), CPL-2 (9 × 6 Å2), and CPL-5 (11 × 6 Å2). Among the three frameworks, CPL-2 exhibits the highest C2H2uptake at ambient conditions as it has moderate pore size and porosity. However, CPL-1 has the best separation performance in the breakthrough experiments with binary gas mixture of C2H2/C2H4, thanks to the optimal pore size nearly excluding C2H4, which is only observed in the state-of-the-art UTSA-300a so far. The DFT calculations were carried out to elucidate the specific adsorption sites for both acetylene and ethylene among these frameworks. The modeling results suggest that binding strength is highly related to aperture size and that CPL-1 shows the highest adsorption selectivity owing to the optimal pore size. This work demonstrates that engineering pore size enables us to fabricate the highly efficient metal–organic framework (MOF)-based adsorbents for specific gas separation on the basis of the isoreticular chemistry.

The efficient separation of xenon (Xe) and krypton (Kr) is one of the industrially important processes. While adsorptive separation of these two species is considered to be an energy efficient process, developing highly selective adsorbent remains challenging. Herein, a rigid squarate-based metal–organic framework (MOF), having a perfect pore size (4.1 Å × 4.3 Å) comparable with the kinetic diameter of Xe (4.047 Å) as well as pore surface decorated with very polar hydroxyl groups, is able to effectively discriminate Xe atoms, affording a record-high Xe/Kr selectivity. An exceptionally high Xe uptake capacity of 58.4 cm3/cm3and selectivity of 60.6 at low pressure (0.2 bar) are achieved at ambient temperature. The MOF exhibits the highest Xe Henry coefficient (192.1 mmol/g/bar) and Xe/Kr Henry selectivity (54.1) among all state-of-the-art adsorbents reported so far. Direct breakthrough experiments further confirm the excellent separation performance. The density functional theory calculations reveal that the strong interaction between Xe and the framework is a result of the synergy between optimal pore size and polar porosity.

The demand for CO2/C2H2separation, especially the removal of CO2impurity, continues to grow because of the high-purity C2H2required for various industrial applications. The adsorption separation of C2H2and CO2via porous materials is gaining a considerable attention as it is more energy-efficient compared with cryogenic distillation. The ideal porous materials are those that preferentially adsorb CO2over C2H2; however, very few adsorbents meet such requirement. Herein, two isostructural cyclodextrin-based CD-MOFs (CD-MOF-1 and CD-MOF-2) were demonstrated to have an inverse ability to selectively capture CO2from C2H2by single-component adsorption isotherms and dynamic breakthrough experiments. These two MOFs showed excellent adsorption capacity and benchmark selectivity (118.7) for CO2/C2H2mixture at room temperature, enabling the pure C2H2to be obtained in only one step. This work revealed that these materials were promising adsorbents for obtaining high-purity C2H2via selectively capturing CO2from C2H2.

ABSTRACTHeat stress is one of the major abiotic stresses that adversely affect growth and yield in Lentinula edodes(Shiitake mushroom) under natural cultivation. In this study, two parental strains (L808 and Lsm9), an F1strain, and an F2population derived from their hybrid progeny were used to evaluate the regeneration of mycelia after heat stress. A multi-level heat stress experiment showed that the dynamics of radial mycelium expansion of the two parents followed a linear equation after heat stress treatment at 37°C for 4–24 h, 42°C for 4–16 h, or 45°C for 4 h. Three indices were selected to describe the regeneration ability of the strains, including the number of regeneration days (NRD), the real growth rate after heat stress (Vregeneration), and the regenerative index (RI). L808 presented a faster rate of regeneration, while Lsm9 had better regeneration quality. The phenotype analysis of the F2population showed that these indices were controlled by multiple genetic factors with high heritability. Four strains were selected from the population, pyramiding the advantages of heat resistance from the two parents. The results will help our understanding of the genetic features of this mushroom after extreme high-temperature stress.