Explore the vast range of titles available.

The fifth-generation (5G) wireless communication has an urgent need for target tracking. Digital programmable metasurface (DPM) may offer an intelligent and efficient solution owing to its powerful and flexible controls of electromagnetic waves and advantages of lower cost, less complexity and smaller size than the traditional antenna array. Here, we report an intelligent metasurface system to perform target tracking and wireless communications, in which computer vision integrated with a convolutional neural network (CNN) is used to automatically detect the locations of moving targets, and the dual-polarized DPM integrated with a pre-trained artificial neural network (ANN) serves to realize the smart beam tracking and wireless communications. Three groups of experiments are conducted for demonstrating the intelligent system: detection and identification of moving targets, detection of radio-frequency signals, and real-time wireless communications. The proposed method sets the stage for an integrated implementation of target identification, radio environment tracking, and wireless communications. This strategy opens up an avenue for intelligent wireless networks and self-adaptive systems. The authors present an intelligent metasurface system that uses a target detection algorithm combined with a depth camera, to automatically detect the position of moving targets and achieve real-time wireless communications. The system can operate for multiple targets in limited ambient light, outdoor and other realistic environments.

Nanostructured magnetic materials provide an efficient tool for light manipulation on sub-nanosecond and sub-micron scales, and allow for the observation of the novel effects which are fundamentally impossible in smooth films. For many cases of practical importance, it is vital to observe the magneto-optical intensity modulation in a dual-polarization regime. However, the nanostructures reported on up to date usually utilize a transverse Kerr effect and thus provide light modulation only for p-polarized light. We present a concept of a transparent magnetic metasurface to solve this problem, and demonstrate a novel mechanism for magneto-optical modulation. A 2D array of bismuth-substituted iron-garnet nanopillars on an ultrathin iron-garnet slab forms a metasurface supporting quasi-waveguide mode excitation. In contrast to plasmonic structures, the all-dielectric magnetic metasurface is shown to exhibit much higher transparency and superior quality-factor resonances, followed by a multifold increase in light intensity modulation. The existence of a wide variety of excited mode types allows for advanced light control: transmittance of both p- and s-polarized illumination becomes sensitive to the medium magnetization, something that is fundamentally impossible in smooth magnetic films. The proposed metasurface is very promising for sensing, magnetometry and light modulation applications. The authors fabricate and investigate the metasurface made of 2D iron-garnet subwavelength nanopillar array on a thin iron-garnet film. It exhibits high quality-factor resonances, leading to a multifold increase in light intensity modulation of the transmitted light with an advantage of P and S polarizations both sensitive to the medium magnetization.

Flexible optical networks require reconfigurable devices with operation on a wavelength range of several tens of nanometers, hitless tuneability (i.e. transparency to other channels during reconfiguration), and polarization independence. All these requirements have not been achieved yet in a single photonic integrated device and this is the reason why the potential of integrated photonics is still largely unexploited in the nodes of optical communication networks. Here we report on a fully-reconfigurable add-drop silicon photonic filter, which can be tuned well beyond the extended C-band (almost 100 nm) in a complete hitless (>35 dB channel isolation) and polarization transparent (1.2 dB polarization dependent loss) way. This achievement is the result of blended strategies applied to the design, calibration, tuning and control of the device. Transmission quality assessment on dual polarization 100 Gbit/s (QPSK) and 200 Gbit/s (16-QAM) signals demonstrates the suitability for dynamic bandwidth allocation in core networks, backhaul networks, intra- and inter-datacenter interconnects. Reconfigurable wavelength-selective devices are essential components of flexible optical networks. Here the authors show a silicon-photonic add-drop multiplexer meeting the strict requirements of telecom systems in terms of broadband operation range, hitless tunability and polarization transparency.

In this paper, a single-feed microstrip antenna (MA) equipped with a transmission-mode focusing metasurface (MS) is proposed to achieve dual-polarization capabilities and superior high-gain radiation performance. The original-feed MA comprises two distinct layers of coaxial-fed tangential patches, enabling it to emit a circular polarization (CP) wave with a gain of 3.5 dBic at 5.6 GHz and linear polarization (LP) radiation with a gain of 4 dBi at 13.7 GHz. To improve the performance of the single-feed MA, a dual-polarization transmission focusing MS is proposed and numerically substantiated. By positioning the originally designed MA at the focal point of the MS, we create a transmission-mode MS antenna system capable of achieving CP and LP radiations with the significantly higher gains of 12.9 dBic and 14.8 dBi at 5.6 GHz and 13.7 GHz, respectively. Measurements conducted on the fabricated dual-polarization focusing MS antenna closely align with the simulation results, validating the effectiveness of our approach. This work underscores the significant potential of dual-polarization high-speed data systems and offers a practical solution for enhancing antenna gains in contemporary wireless communication systems.

Spin waves may constitute key components of low-power spintronic devices. Antiferromagnetic-type spin waves are innately high-speed, stable and dual-polarized. So far, it has remained challenging to excite and manipulate antiferromagnetic-type propagating spin waves. Here, we investigate spin waves in periodic 100-nm-wide stripe domains with alternating upward and downward magnetization in La0.67Sr0.33MnO3 thin films. In addition to ordinary low-frequency modes, a high-frequency mode around 10 GHz is observed and propagates along the stripe domains with a spin-wave dispersion different from the low-frequency mode. Based on a theoretical model that considers two oppositely oriented coupled domains, this high-frequency mode is accounted for as an effective antiferromagnetic spin-wave mode. The spin waves exhibit group velocities of 2.6 km s−1 and propagate even at zero magnetic bias field. An electric current pulse with a density of only 105 A cm−2 can controllably modify the orientation of the stripe domains, which opens up perspectives for reconfigurable magnonic devices.Current pulses of 105 A cm−2 can control the orientation of 100-nm-wide stripe domains in La0.67Sr0.33MnO3 and spin waves of 10 GHz can propagate along these domains with a group velocity of 2.6 km s−1.

Compared to the conventional metasurface design, machine learning-based methods have recently created an inspiring platform for an inverse realization of the metasurfaces. Here, we have used the Deep Neural Network (DNN) for the generation of desired output unit cell structures for both TE and TM polarized waves which its working frequency can reach up to 45 GHz. To automatically generate metasurfaces over wide frequencies, we deliberately design 8 annular models; thus, each generated meta-atoms in our dataset can produce different notches in our desired working frequency. Compared to the general approach, whereby the final metasurface structure may be formed by any randomly distributed “0” and “1”, we propose here a confined output configuration. By confining the output, the number of calculations will be decreased and the learning speed will be increased. Establishing a DNN-confined output configuration based on the input data for both TE and TM polarized waves is the novelty to generate the desired metasurface structure for dual orthogonal polarizations. Moreover, we have demonstrated that our network can attain an accuracy of 92%. Obtaining the final unit cell directly without any time-consuming optimization algorithms for both TE and TM polarized waves, and high average accuracy, open beneficial ways for the inverse metasurface design; thus, the designer is required only to focus on the design goal.

Extensive research on millimeter-wave frequency bands is currently in rapid development throughout the world, specifically at an operating frequency of 28 GHz, and Malaysia is no exception. The most conventional patch antennas covered a limited polarization feature of single polarization of radiated beam signals. In order to meet the high demands of network users with a higher data rate, the radiated beam signal coverage should be as wide as possible to ensure the stability and consistency of the received signals for the users. This leads to the development of the dual polarization feature of single-layer antenna design. In this work, a dual element (70 x 70 mm 2 ) patch antenna at 28 GHz has been designed using CST Studio Suite and fabricated using Rogers RT5880. The antenna has been oriented to the right (+45°) and to the left (-45°) from the normal plane to realize a dual linear polarization state. The simulation and measurement results show that the reflection coefficient obtained for all antennas is less than -10 dB. The simulated and measured radiation patterns of the antennas are also shown in this paper. It is observed that the proposed antenna achieves a dual-polarized state with a higher gain of 11.16 dBi, compared to 4.97 dBi for a single patch. This dual-polarized antenna can be applied in various applications, particularly for MIMO and 5G mobile communication networks.

In this paper, a dual-polarized antenna with high isolation working at millimeter wave(mmW) frequency band is attempted. The proposed antenna can provide two orthogonal ports fed by only one square radiation patch with more than 30 dB isolation. In addition, the antenna can obtain a peal gain level of around 8dB for two ports. A more simple structure, which consists of two substrates and one foam layer rather than traditional two substrates, a cover plate and two foam layers, makes it more suitable for arrays form and easier for fabrication.

This letter proposes a novel wave-transparent and decoupling antenna in broadband dual-Polarized dual-Band shared-aperture array. It is implemented by kneading the double-arrow-stripe-shaped decoupling structure into the frequency-selective metasurface structure of the lower-frequency-band (LFB) antenna arms. The LFB antenna radiator can be considered as frequency-selective and array-decoupling metasurface for the higher-frequency-band (HFB) antennas placed below. The antenna system consists of 2 × 2 HFB (3.3-3.6 GHz)arrays and an LFB (1.65-2.58 GHz) antenna with wave-transparent and decoupled structure (WTDS). Then, without adding additional structure, the in-band isolations of co- and cross-polarized between HFB antennas are promoted to >25.6 dB and >25 dB only by relying on the antenna form of the LFB antenna itself.

The South Pole Telescope Summertime Line Intensity Mapper (SPT-SLIM) is a pathfinder experiment that will demonstrate the use of on-chip filter-bank spectrometers for mm-wave line intensity mapping. The SPT-SLIM focal plane consists of 18 dual-polarization filter-bank spectrometers covering 120–180 GHz with resolving power of 300, coupled to aluminum kinetic inductance detectors. A compact cryostat holds the detectors at 100 mK. SPT-SLIM will be deployed to the 10-m South Pole Telescope for observations during the 2023–2024 austral summer without removing the primary receiver. We discuss the overall instrument design, expected detector performance, and sensitivity to the carbon monoxide line signal at 0.5 < z < 2 . The technology and observational techniques demonstrated by SPT-SLIM will enable next-generation line intensity mapping experiments that constrain cosmology beyond the redshift reach of galaxy surveys.