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It is essential to perform end-to-end performance testing of multiple-input-multiple-output (MIMO) systems under realistic propagation channel conditions. However, due to the highly integrated and compact radio frequency (RF) system design, the traditional conducted cable testing method is getting more and more problematic. The wireless cable solution, which can achieve the equivalent functionality of the conducted cable testing without actual RF coaxial cables, has attracted huge attention from the industry and standardization for over-the-air (OTA) testing in recent years. However, the state-of-the-art solutions to achieve wireless cable testing necessitate at least reference signal received power (RSRP) reporting per device under test (DUT) antenna port for MIMO capable terminals, which is demanding and might not be accessible for commercial DUTs. In this work, a novel wireless cable solution based only on the maximum RSRP measurement of all DUT antenna ports is proposed, which can significantly alleviate the requirement of DUT RSRP reporting. To achieve the wireless cable testing, a novel calibration procedure is proposed to determine the transfer matrix between the probe antenna ports and the DUT antenna ports based on the DUT maximum reported RSRP measurement. The proposed algorithm is theoretically derived and experimentally validated for a 2 × 2 MIMO system, where the isolation of above 25 dB is achieved for the measurement setup. The numerical simulation and experimental validation demonstrate the efficiency and robustness of the proposed algorithm.

Phased array calibration is typically carried out inplane-wave conditions, which requires expensive far-field setups.This letter presents a novel phased array calibration methodbased on measured complex array signal, which works in thecost-effective compact testing setup. The basic principle is toemploy multi-probe antennas in a short measurement distancesuch that we can effectively retrieve the array element patternsin the boresight direction based on the recorded complex signalsat the multiple probes using the interpolation technique. Boththeoretical derivations and measurement validations are providedto demonstrate the effectiveness of the proposed method.

Over-the-air (OTA) radiated testing is seen inevitablefor future radio devices due to integrated transceiverradio designs. Wireless cable solution, which can achieve traditionalcabled testing functionality over-the-air, has attractedgreat attention from industry, standardization and academia inrecent years for multiple-input multiple-output (MIMO) deviceperformance testing. In state-of-the-art wireless cable solutions,the compensation of the transfer matrix between the OTA probesand antenna ports of device under test (DUT) is implementedwith the help of radio channel emulators (CEs). However,the radio CEs are not customized for such implementations,leading to expensive system and waste of valuable CE resource.Employing more probe antennas is a known and effective strategyto improve the robustness and quality of the wireless cableconnection, which would further increase the system cost withexisting implementations. To address these issues, a novel wirelesscable implementation employing a stand-alone programmableamplitude and phase control network is proposed. Though simpleand cost-effective, the proposed scheme is demonstrated to workin practice and it is applicable for more generic testing scenarioswhere a CE is not required. The experimental validation measurementsobtained in the VNA based passive measurement setupas well as in the active measurement setup clearly demonstratethe effectiveness and robustness of the proposed scheme.

Owing to the advantages of ultra-wide bandgap and rich material systems, gallium oxide (Ga2O3) has emerged as a highly viable semiconductor material for new researches. This article mainly focuses on the growth processes, material characteristics, and applications of Ga2O3. Compared with single crystals and the epitaxial growth of other wide-bandgap semiconductors, large-size and high-quality β-Ga2O3 single crystals can be efficiently grown with a low cost, making them highly competitive. Thanks to the availability of high-quality single crystals, epitaxial films, and rich material systems, high-performance semiconductor devices based on Ga2O3 go through a booming development in recent years. The defects and interfaces of Ga2O3 are comprehensively analyzed owing to their significant influence on practical applications. In this study, the two most common applications of Ga2O3 materials are introduced. The high breakdown electric field, high working temperature, and excellent Baliga's figure-of-merit of Ga2O3 represent an inspiring prospect for power electronic devices. In addition, the excellent absorption in deep-ultraviolet band provides new ideas for optoelectronic detectors and ensures the dramatic progress. Finally, the summary, challenges, and prospects of the Ga2O3 materials and devices are presented and discussed.

Accurate knowledge of initial complex excitation coefficients for phased-array elements is essential to ensure accurate array performance. In the literature, many array calibration algorithms have been proposed for this purpose, which generally requires customized phase setting for individual phase shifters connected to array elements. In this article, a new array calibration method is proposed for phased array operating in beam-steering mode only, that is, phase shifts of elements are only simultaneously set according to the beam-steering directions, and therefore, there is no need for dedicated individual element phase tuning. The proposed method requires a minimum number of complex-signal measurements in principle, which enables fast measurement. Furthermore, it is found that the performance of the proposed method is determined by the beam-steering matrix, whose condition number is mainly ruled by the beam-steering angle interval. The proposed method is numerically simulated and experimentally validated in a millimeter-wave (mmWave) phased-array antenna-in-package (AiP) platform at 28 GHz. The proposed method presents good agreement with the well-known rotating element electric field vector (REV) array calibration method, with an amplitude error and phase error within ±0.5 dB and ±5°, respectively. Furthermore, the reconstructed array pattern with the proposed method offers excellent match with the measured array pattern.

Phased array calibration is essential to ensure accuratearray radiation performance. This paper proposes animproved calibration method based on complex signals in ananechoic chamber for phased arrays that can only operatein its default beam-steering mode with limited beam-steeringangular ranges. The basic principle is to convert the arrayfactors associated with the multi-probe locations into the beamsteeringfactors of the array, which can virtually widen the beamsteeringangular range. The broadened angular range can lowerthe condition number of the phase setting matrix and thereforeimprove the calibration accuracy. Both theoretical derivationsand measurement validation are provided to demonstrate theeffectiveness and enhancement of the proposed method.

Supplemental digital content is available in the text., Objective The intestinal barrier injury caused by severe acute pancreatitis (SAP) can induce enterogenous infection, further aggravating the inflammatory reactions and immune responses. This study aimed to test the hypothesis that emodin protects the intestinal function and is involved in the immune response in SAP. Methods The network pharmacology was established using the Swiss target prediction and pathway enrichment analysis. The SAP mice model was induced by cerulein (50 μg/kg) and lipopolysaccharide (10 mg/kg) hyperstimulation. The pharmacological effect of emodin in treating SAP was evaluated at mRNA and protein levels by various methods. Results The network analysis provided the connectivity between the targets of emodin and the intestinal barrier–associated proteins and predicted the BAX/Bcl-2/caspase 3 signaling pathway. Emodin alleviated the pathological damages to the pancreas and intestine and reduced the high concentrations of serum amylase and cytokines in vivo. Emodin increased the expression of intestinal barrier–related proteins and reversed the changes in the apoptosis-related proteins in the intestine. Simultaneously, emodin regulated the ratio of T helper type 1 (TH1), TH2, TH17, γδ T cells, and interferon γ/interleukin 17 producing γδ T cells. Conclusions These findings partly verified the mechanism underlying the regulation of the intestinal barrier and immune response by emodin.

This communication presents a novel quad-ridged horn (QRH) antenna incorporating a balanced feed. A cross-shaped fusiform structure is mounted in the center of the QRH. The fusiform structure has the effect of suppressing the cross-polarization component by improving the conventional QRH $TE_{11}$ mode. The communication presents an equivalent circuit that has been derived for the proposed balanced feed network. Four SMA probes are symmetrically distributed around the horn wall and the inner conductors of the two probes facing each other are connected. The cross-polar level, within a 30° solid angle, is less than −23 dB from 2 to 6 GHz. The measured isolation between two orthogonal linearly polarized ports is higher than 42 dB and the return loss is lower than −15 dB over the entire working frequency band.

Surface treatment after dry etching is vital to enhance the surface quality of the material and thus improve device performance. In this Letter, we identified the majority surface states induced by the dry etching of β-Ga

Antenna array composed of subarrays is a widely used array structure in the fifth-generation (5G) base stations (BSs), which can offer both high gain beam and beam-steering capability. Generally, subarray-structured BS antennas consist of a number of subarrays, each composed of a few antenna elements, making the array diagnosis a pronounced and challenging problem. A fast diagnosis method, which can be conducted in the near-field of the BS array, is presented for BS array of subarrays in this letter. The objective is to detect antenna failures, which can be caused by the disconnection at either the feed of subarray or the feed of the antenna element in the subarray, based on complex array signals recorded by only a few probes with a short measurement distance. The diagnosis is achieved by a novel two-stage measurement procedure based on solving linear equations. Finally, an array composed of four subarrays with 24 antenna elements in total was used to validate the effectiveness and robustness of the proposed method in a practical setup.

Plane-wave generators (PWGs) for over-the-air testing of 5G base stations offer the advantages of efficiency and economy. Many new bands, such as n28, are progressively being introduced, driving the bandwidth improvement of PWGs. The cost of amplitude–phase control networks is also increased by the broadband range required for testing. In view of the above challenges, in this paper, a low-frequency ultra-wideband PWG for testing 5G base stations is reported. Firstly, an electrically small antenna unit based on the Vivaldi antenna is design for the PWG. The antenna unit has a wide operating band and compact size, allowing it to reach a quarter of the minimum frequency wavelength. Then, the operating band from 700 MHz to 4 GHz is divided into three sub-bands, and the amplitude and phase excitations within each sub-band are optimized with multiple frequency points. Finally, the designed ultra-wideband PWG is simulated and experimentally tested. The designed 2.64 m one-dimensional linear-array PWG is able to produce a 1.5 m × 1.32 m quiet zone with less than 1.0 dB and 10°. The results of the radiation pattern measurements for the base station agree reasonably well with the MVG SG128.

Single-photon emitters based on intrinsic defects in silicon carbide (SiC) are promising as solid-state qubits for the quantum information storage, whereas defect engineering in a controllable manner still remains challenging. Herein, the thermally-driven defect dynamic reaction in the ion implanted 4H-SiC has been exploited through the optical emission spectra of defects. For the heavy-ion (Si or Ar) implanted samples with abundant Frenkel pairs, the silicon vacancies (VSi) are energetically converted into the carbon antisite-vacancy pair (CSi-VC) upon annealing till 1300 °C for 30 min, accompanied with the gradual lattice recovery and local strain relaxation. The further temperature elevation dissociates the metastable CSi-VC into carbon antisite (CSi) and carbon vacancy (VC), as supported by the consequent quenching of the (CSi-VC)-related emission at 700 nm. Thus, the whole defect reaction is probed as the vacancy interconversion from VSi to VC with the byproduct of stacking faults. In contrast, the intermediate CSi-VC complexes are not energetically favorable during the annealing of the H-implanted sample, which results from the negligible generation of Frenkel pairs, as supported by the x-ray diffraction patterns and Raman scattering analysis. These findings provide guidance for defect engineering in SiC toward the creation of reliable single photon emitters.

In this work, vertical NiO/Ga2O3 heterojunction diodes (HJDs) integrated with SiNx/Al2O3 double-layered insulating field plate (FP) structures have been demonstrated. With the additional post-annealing, the resultant diode exhibits a decreased differential specific on-resistance ( $\text{R}_{\mathrm{ on,sp}}$ ) of 5.4 $\text{m}\boldsymbol{\Omega } \cdot $ cm2 and an enhanced breakdown voltage (BV) of 1036 V. The improved performance is attributed by the combination of the FP-suppressed crowding electric field at the device edge and the reduced trap density at the NiO/Ga2O3 interface. In particular, the near-unity ideality factor has been achieved for this p-n HJD at an elevated temperature of 275 °C, indicating that the diffusion current is dominated. The high-temperature operation capability is owing to the quality improvement of NiO/Ga2O3 interface, where the Shockley-Read-Hall (SRH) recombination mediated by deep-level defects within the depletion region is thus suppressed.

Antenna-in-package (AiP) technology has been a main design scheme of millimeter-wave (mmWave) phased array antennas for 5G communications. The beamforming pattern of mmWave phased array AiP is steered by controlling the amplitude and phase excitations of AiP elements. It would be helpful to evaluate the control accuracy of complex excitations and to reliably calibrate mmWave AiP. However, these tasks are not trivial and time consuming in practice, especially when the number of AiP elements is large. To address this problem, this article presents an efficient and automated mmWave phased array experimental platform. To reduce measurement time, a control software is developed to automatically control the AiP and measurement instruments simultaneously. This experimental platform has flexible gain and phase control of AiP element excitations, and customized measurements in an automated and efficient way can be realized. The effectiveness of the experimental platform is demonstrated by several measurement campaigns, where control accuracy, array calibration, and beam steering for mmWave phased array AiP are extensively investigated.

A novel anchorage method of CFRP grid in mortar named intersect-type anchorage method was proposed in this paper. In order to verify the application feasibility of this novel anchorage method in practical engineering, two phases of pull-out tests including single-direction pull-out tests and bidirectional pull-out tests were carried out. The number of grid points and anchorage conditions were selected as changing parameters. The maximum tensile loads, failure patterns, load–displacement curves of test specimens and load–strain curves of CFRP grids were obtained. The ultimate resistant actions, tensile bearing modes of grid points, tensile stress transfer process, coupling effect between the bond action of vertical grid and the resistant action of grid points and the failure mechanism were discussed. The research results showed that the intersect-type anchorage method is a favorable anchorage method for CFRP grid in mortar and the bond action of vertical grid play a dominant role for the anchorage action of CFRP grid in mortar rather than the resistant action of horizontal grid. In order to make full use of the tensile strength of CFRP grid, the number of grid points in intersecting part was not less than two.

This letter presents a sub-6 GHz cost-effective wideband dual-polarized plane wave generator (PWG) design for the fifth-generation (5G) base station over-the-air test. The proposed nonuniform PWG design is composed of 256 elements and has a dimension of 1.7 m × 1.7 m. Several novel strategies are proposed and implemented to reduce the cost and complexity. To reduce the feeding network complexity and mutual coupling among PWG elements, a novel tapered amplitude-only excitation method (i.e., with the same relative phase excitations among all PWG elements) is proposed. To reduce the number of channels in the phase and amplitude control network, a four-element subarray is applied. Furthermore, the wideband PWG element design and nonuniform configuration are applied to support for ultrawideband operations from 2 to 5 GHz. The proposed PWG design is numerically simulated and experimentally validated. A cylindrical quiet zone of a diameter of 0.9 m and a depth of 0.9 m, with 2.1 m distance to the PWG, is achieved in the measurement for the considered bandwidth, with the typical peak-to-peak E-field amplitude and phase variations less than ±1.25 dB and ±7.5°, respectively, which demonstrated its effectiveness and robustness.

This paper presents the experimental results of four-point bending tests for reinforced concrete (RC) beams strengthened by carbon fiber reinforced polymer (CFRP) grids and sprayed polymer-cement-mortar (PCM). The reinforced arrangements of CFRP grids, stirrups and longitudinal steel rebars were selected as changing parameters. The maximum loads, mid-span deflections and strains for the PCM, longitudinal steel rebars, stirrups and CFRP grids were obtained. The mechanical behavior of CFRP grids and the cooperation work performance between CFRP grids and steel rebars were investigated emphatically. The research results indicated that the shear strengthening effect of the CFRP grid-PCM reinforcing layers bonded along both sides of RC beams was sufficient. The shear contribution of the vertical CFRP grid was similar to that of the stirrup, but the stress distribution of vertical CFRP grid was not uniform due to the resistant action of grid points. Moreover, the vertical CFRP grids bore the lateral extruding action with opposite directions in tension and compression zones due to the compressive and tensile behavior of horizontal CFRP grids, resulting in the complex stress state of the vertical grid which differs from the stirrup. There exists the cooperation work between CFRP grids and steel rebars in shear strengthening RC beams. So as to clarify the shear mechanism of RC beams strengthened by CFRP grids and PCM, the complex stress state of vertical CFRP grid, influence of the horizontal CFRP grid and the preconditions for the normal work of CFRP grid should be taken into account. The proposed shear capacity calculation formula based on truss-arch model could satisfy the design requirements.

This article presents a polarization-reconfigurable wideband high-gain antenna based on liquid metal tuning. The antenna consists of a center-feed circular patch antenna with a C-shaped slot as the driven element. To broaden the bandwidth and improve the realized gain, a parasitic circular disc and 13 circular directors are employed. The direction of polarization can be tuned by changing the location of the liquid metal alloy contained in the tube. The relationship between the dimensions and the maximally achievable gain has been analyzed. The antenna has exhibited a −10 dB impedance bandwidth from 4.3 to 5.3 GHz (a fractional bandwidth of 21.2%). A 14.4 dBi gain is achieved at 5.3 GHz. The simulation and measurement results show good agreement with each other.

This letter shows how slugs of liquid metal can be used to connect/disconnect large areas of metalization and achieve a radiation performance not possible by using conventional switches. The proposed antenna can switch its operating bandwidth between ultrawideband and narrowband by connecting/disconnecting the ground plane for the feedline from that of the radiator. This could be achieved by using conventional semiconductor switches. However, such switches provide point-like contacts. Consequently, there are gaps in electrical contact between the switches. Surface currents, flowing around these gaps, lead to significant back radiation. In this letter, the slugs of a liquid metal are used to completely fill the gaps. This significantly reduces the back radiation, increases the bore-sight gain, and produces a pattern identical to that of a conventional microstrip patch antenna. Specifically, the realized gain and total efficiency are increased by 2 dBi and 24%, respectively. The antenna has potential applications in wireless systems employing cognitive radio (CR) and spectrum aggregation.

Loganin, a major bioactive iridoid glycoside derived from Cornus officinalis, exerts different beneficial biological properties. Recently, loganin has been reported to exhibit potential anti-inflammatory effects in the intestinal tissues, while the detailed mechanisms remain elusive. This study aimed to investigate whether loganin could inhibit the inflammatory response in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and to explore possible molecular mechanisms involved in this process. Results showed that oral administration of loganin significantly decreased body weight loss, disease activity index, colon shortening, myeloperoxidase (MPO) activity and pathologic abnormalities in UC mice. Loganin obviously inhibited the mRNA and protein levels of IL-6, TNF-α and IL-1β in colon tissues from UC mice. Furthermore, loganin remarkably reduced macrophage M1 polarization in UC mice evidenced by reduced the number of F4/80 and iNOS dual-stained M1 macrophages, and the expression of M1 macrophage-related pro-inflammatory chemokines/cytokines including MCP-1, CXCL10 as well as COX-2. Further investigation showed that loganin upregulated the mRNA and protein levels of Sirt1, with the inhibition of NF-κB-p65 acetylation in colon tissues from UC mice. Moreover, Sirt1-specific inhibitor Ex527 administration abolished the anti-inflammatory and anti-macrophage M1 polarization effects of loganin in UC. Thus, loganin could inhibit M1 macrophage-mediated inflammation and modulate Sirt1/NF-κB signaling pathway to attenuate DSS-induced UC. Loganin was considered as a viable natural strategy in the treatment of UC.[Figure: see text].

Benefitted from progress on the large-diameter Ga2O3 wafers and Ga2O3 processing techniques, the Ga2O3 power device technology has witnessed fast advances toward power electronics applications. Recently, reports on large-area (ampere-class) Ga2O3 power devices have emerged globally, and the scope of these works have gone well beyond the bare-die device demonstration into the device packaging, circuit testing, and ruggedness evaluation. These results have placed Ga2O3 in a unique position as the only ultra-wide bandgap semiconductor reaching these indispensable milestones for power device development. This paper presents a timely review on the state-of-the-art of the ampere-class Ga2O3 power devices (current up to >100 A and voltage up to >2000 V), including their static electrical performance, switching characteristics, packaging and thermal management, and the overcurrent/overvoltage ruggedness and reliability. Exciting research opportunities and critical technological gaps are also discussed. National Science Foundation [ECCS-2230412]; Center for Power Electronics Systems High Density Integration Industry Consortium; [ECCS-2100504] Published version We appreciate the in-person discussions with Ga2O3 researchers in IWGO2022. The work at Virginia Tech is in part supported by National Science Foundation under Grants ECCS-2100504 and ECCS-2230412 and in part by the Center for Power Electronics Systems High Density Integration Industry Consortium.

This paper investigates the calibration methods appropriate to the phased array calibration in practical measurement setups. The rotating element electric field vector (REV) method, fast amplitude-only calibration method, and complex amplitude calibration method are compared and analyzed in the same measurement setup. The objective is to investigate the robustness of the discussed algorithms with different measurement ranges, with or without the support of array element on/off operation. A 4×8 uniform rectangular array (URA) is used to validate the three different calibration methods. The measurement results indicate that array element on/off measurement in the far field is suitable to be a reference calibration method in practical setup. The REV and complex amplitude calibration methods present comparable accuracy while fast amplitude-only calibration method provides less accurate calibration results in this measurement. Further, it was demonstrated that with element on/off data available, same calibration accuracy can be achieved either in small or large measurement ranges for the three different calibration methods. However, when the element on/off data is not available, the array calibration accuracy deteriorates with small measurement range. This paper presents the method to calibrate the phased array antenna in near-field by using the element on/off data. This is a very useful method in massive production line calibration. The calibration errors of different calibration methods are analyzed. Furthermore, this paper also analyzes the uncertainty of each method.