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The fabric‐based pneumatic exosuit is now a hot research topic because it is lighter and softer than traditional exoskeletons. Existing research focuses more on the mechanical properties of the exosuit (e.g., torque and speed), but less on its wearability (e.g., appearance and comfort). This work presents a new design concept for fabric‐based pneumatic exosuits: volume transfer, which means transferring the volume of pneumatic actuators beyond the garment's profile to the inside. This allows for a concealed appearance and a larger stress area while maintaining adequate torques. In order to verify this concept, a fabric‐based pneumatic exosuit is developed for knee extension assistance. Its profile is only 26 mm and its stress area wraps around almost half of the leg. A mathematical model and simulation is used to determine the parameters of the exosuit, avoiding multiple iterations of the prototype. Experiment results show that the exosuit can generate a torque of 7.6 Nm at a pressure of 90 kPa and produce a significant reduction in the electromyography activity of the knee extensor muscles. It is believed that volume transfer can be utilized prevalently in future fabric‐based pneumatic exosuit designs to achieve a significant improvement in wearability. This work presents a new design concept for fabric‐based pneumatic exosuits: volume transfer, which means transferring the volume of pneumatic actuators beyond the garment's profile to the inside. Using volume transfer can achieve a significant improvement in wearability of exosuits.

This paper presents an ultralow profile, low passive intermodulation (PIM), and super-wideband in-building ceiling mount antenna that covers both the cellular and public safety ultra high frequency (UHF) band for distributed antenna system (DAS) applications. The proposed antenna design utilizes a modified 2-D planar discone design concept that is miniaturized to fit into a small disc-shaped radome. The 2-D planar discone has an elliptical-shaped disc monopole and a bell-shaped ground plane, a stub at the shorting path, with asymmetrical structure and an additional proximity coupling patch to maximize the available electrical path to support the 350 MHz band range. The proposed design maximizes the radome area with a reduction of about 62% compared to similar concept type antennas. Besides, the proposed design exhibits an improved radiation pattern with null reduction compared to a typical dipole/monopole when lies at the horizontal plane. A prototype was manufactured to demonstrate the antenna performance. The VSWR and radiation pattern results agreed with the simulated results. The proposed antenna achieves a band ratio of 28.57:1 while covering a frequency range of 350–10000 MHz. The measured passive intermodulation levels are better than −150 dBc (2 × 20 Watts) for 350, 700 and 1920 MHz bands.

Background The Low-profile Visualized Intraluminal Support (LVIS) device is a self-expanding, nitinol, single-braid, closed-cell device that was recently developed for endovascular embolization of intracranial aneurysms. However, current knowledge regarding the use of LVIS devices to treat vertebral and basilar artery aneurysms is limited. We aimed to evaluate the feasibility, efficacy, and safety of the LVIS device for treating vertebral and basilar artery aneurysms. Methods Between January 2015 and December 2017, patients with vertebral and basilar artery aneurysms treated using LVIS stents were enrolled in this study. We analyzed patients’ demographic, clinical and aneurysmal characteristics, procedural details, complications, and angiographic and clinical follow-up results. Results We identified 63 patients with 64 vertebral and basilar artery aneurysms who underwent treatment with ( n  = 59) or without ( n  = 5) LVIS stenting, including 10 patients with ruptured aneurysms. Forty-one aneurysms were located at the vertebral artery, and 23 at the basilar artery. Intraprocedural-related complications developed in three (4.8%) patients, while none of these patients developed morbidities or died during follow-up. Three patients developed post-procedural complications (4.8%). Two patients experienced ischemic events immediately post-procedure. A minor permanent morbidity developed in one of the two patients (1.6%). The mortality rate was 1.6%, for that the patient died of brainstem hemorrhage after 1 month of follow-up. At a mean follow-up of 12.5 months, 39/43 (90.7%) patients had stable or improved aneurysms, and four (9.3%) had recanalized. Conclusions LVIS device of vertebral and basilar artery aneurysms may be an acceptable safety profile and may represent a reasonable treatment option in the short-term. Long-term and larger cohort studies are necessary to validate our results.

We report here that spiral and curl antennas are essentially the same when using the moment method. This aids in the understanding and design of the two antennas, and serves as the groundwork for new ideas regarding antennas. First, the spiral antenna height above the ground plane was gradually reduced, and at each height, the spiral configuration parameters were optimized for an axial ratio of less than 0.1 dB. It was found that the spiral antenna had configuration parameters almost the same as those for a curl antenna at a height of 0.15 wavelengths. Next, the curl antenna was analyzed with a reduced height. The antenna, at a height of 0.10 wavelengths, showed a 3 dB axial ratio bandwidth of 3%, with a VSWR of less than two. The analysis results are verified with experimental results.

This study describes the design of a wideband, low-profile shared aperture antenna operating at P-band and Ku-band. This antenna operates with dual-linear polarisation in P-band and single-linear polarisation in Ku-band. In this antenna design, it consists of one P-band microstrip patch antenna and an 8 × 8 Ku-band aperture-coupled patch array. The antenna covers from 330 to 420 MHz in the P-band and from 14.27 to 16.20 GHz in Ku-band with |S11| better than − 10 dB, which translates to 24 and 13% bandwidth in P- and Ku-band, respectively. The overall height of the antenna is about 80 mm, approximately 0.09λ at the lowest frequency. The cross polarisation is better than − 20 dB in the P-band and − 26 dB in the Ku-band. There is virtually no coupling between the P- and Ku-band. The measured gain varies from 6.5 to 7.5 dBi in the P-band and from 22.5 to 23.4 dBi in Ku-band.

A wideband microstrip series-fed magnetic dipole array antenna is proposed. The five-element dipole array antenna is designed to achieve both wide bandwidth and high gain because of its microstrip series feeding structure. The low-profile low-cost array is suitable for applications such as wideband high-gain wireless communications. Measured and simulated results are in good agreement. The measured impedance bandwidth of the array is enhanced up to 28.6% (5.0–6.7 GHz). The radiation patterns show its advantages of high gain (about 10 dBi), endfire radiation and vertical polarisation.

Eliminating the electromagnetic interaction of a device with its background is a topic which attracts considerable attention both from a theoretical as well as from an experimental point of view. In this work, we analyze an infinite two‐dimensional planar microstrip antenna, excited by an incident plane wave, and propose its potential operation as a low‐profile receiving antenna, by suitably adjusting the parameters of its cloaking superstrate. We impose a semi‐analytic integral equation method to determine the scattering characteristics of the microstrip antenna. The method utilizes the explicit expressions of the Green's function of the strip‐free microstrip and yields the surface strip's current as the solution of a suitable linear system. Subsequently, the antenna's far‐field response is obtained. Numerical results are presented for the achieved low profile of the receiving antenna, by choosing suitably the cloaking superstrate parameters. It is demonstrated that for specific cloaking parameters the scattered field by the antenna is considerably reduced, while the received signal from the antenna is maintained at sensible levels. We point out that the material values achieving this reduction correspond to a superstrate filled with anϵ‐near‐zero or a low‐index metamaterial. Finally, the variations of the device reaction for various superstrates are depicted, concluding that for optimized superstrate's parameters, the reaction values are significantly reduced, while at distinct scattering angles even approach zero. Key Points For specific cloaking parameters the scattered field from the antenna is reduced Materials achieving the reduction correspond to ENZ or low‐index metamaterials For optimized superstrate parameters the reaction is significantly reduced

The reflection coefficient phase is studied for four different artificial magnetic conductors (AMCs) having canonical frequency selective surface (FSS)-type two-dimensional periodic structures to be used as back reflectors for an aperture antenna. The bidirectional circularly polarised (CP) radiation of the octagonal-shaped aperture (OSA) antenna is made unidirectional using these AMC surfaces as ground planes. The antenna height measured from the upper surface of AMC reflector to the OSA radiator is chosen to be small to realise low-profile antenna: 0.0825λo at the lowest analysis frequency of 4.5 GHz. Different antenna parameters like voltage standing wave ratio (VSWR) of 2, 3-dB axial ratio (AR) bandwidth, gain, and front-to-back ratio are studied and compared for these four AMCs and the conventionally used perfect electric conductor (PEC) ground plane as back reflectors. Four different aperture shapes with fixed aperture perimeter are designed to integrate with the square-loop AMC as back reflector to realise a low-profile unidirectional wideband CP aperture antenna. Hexagonal-shaped aperture antenna over the square-loop AMC shows the largest measured 3-dB AR bandwidth of 23.33% (5.65–7.05 GHz), VSWR of 2 bandwidth of 36.67% (5.16–7.36 GHz), and the gain of around 7 dBic over the band for overall antenna volume of 0.72λo × 0.60λo × 0.19λo at 6.0 GHz.

This study discusses the design of a low-profile metamaterial-based antenna consisting of a 3 × 5 array of Hilbert shaped unit cells organised as a rectangular patch. The antenna is backed by with a partial ground plane loaded with square electromagnetic band gap defects for energy harvesting applications in the context of ultra-wideband self-powered wearable wireless devices. The antenna is mounted on a 28 × 32 mm FR4 substrate, with a thickness of 0.394 mm, a relative permittivity of 4.2 and a loss tangent of 0.02. The antenna is also printed on a flexible solar panel for self-powered devices through solant–rectenna output terminals. The proposed solant–rectenna is found to cover the frequency range from 0.8 up to 10 GHz. The I–V characteristics of the solar panel are measured with and without the antenna structure to realize low shadowing effects. After that, the solant radiofrequency (RF) port is connected to a rectifier circuit to create a rectenna port that collects the RF energy and converts it to an output DC voltage at 0.915 GHz. It is found that the proposed rectenna provides an output DC voltage of 1.42 V with a conversion efficiency of 90%.

A new low-profile wideband linear-to-circular polarization conversion microstrip slot antenna based on a metasurface for C-band satellite communication applications is proposed in this paper. The metasurface basically consists of four unit cells with parasitic square cross gaps arranged in a 2 × 2 layout. By loading the metasurface on the microstrip slot antenna, linearly polarized (LP) waves from the source antenna are converted into circularly polarized (CP) waves. Then, by etching three more parasitic square cross gaps in the middle of the metasurface, enhanced impedance bandwidth and axial ratio bandwidth (ARBW) are achieved. Furthermore, an equivalent circuit and a phase analysis are presented to explain how a wide ARBW is realized by the metasurface. A final model with an overall size of 36 × 36 × 3.5 mm3 (approximately 0.65λ0 × 0.65λ0 × 0.06λ0 at 5.5 GHz) was designed and fabricated. The measured S11 bandwidth and 3 dB ARBW were 39.25% from 4.28 GHz to 6.37 GHz and 17.77% from 5.18 GHz to 6.19 GHz, respectively. As a result, the proposed antenna shows great potential for satellite communication applications due to its low profile and compact structure, wide impedance bandwidth, and wide axial ratio bandwidth.