Slot Insertion Research Articles

Slotted lightweight steel sections for thermal improvement of building envelopes

AbstractThin‐walled steel sections are used as substructures in multi‐shell constructions of metal facades to create space for thermal insulation. They transfer parallel and vertical loads acting on the outer cladding into the load‐bearing system. Thus, they penetrate the layer of thermal insulation and form a thermal bridge. The resulting thermal losses can be e.g. compensated by higher insulation thicknesses or the change of material selection, but both options usually come along with an increased demand of material and additional costs. By inserting slots in the webs of the steel sections the thermal bridge effect can be reduced. The use of one‐piece substructures enables a faster and thus more cost‐effective installation compared to classic two‐part substructures consisting of a bracket and mounting rail system. Although linear components initially exhibit a greater thermal bridge effect, due to the prolongation of the heat flow through slotted webs these can be thermally improved. However, the insertion of slots weakens the section, which requires the consideration of its load‐bearing behaviour. The improvement of thermal behaviour and the reduction of the load‐bearing capacity is investigated in ongoing research. First results show that both thermal and structural requirements of building practice can be achieved by the investigated slotted steel sections.

Breast Tumor Detection, Sizing and Localization Using a 24-Element Antenna Array.

This paper proposes a simple and novel design for breast cancer detection, sizing and localization. A miniature-sized antenna of volume 10 × 10 × 1.6 mm3 is designed at an optimized frequency of 7.98 GHz with a positive gain using the fractal theory; it is based on two nested folds connected to each other using repeated lines, discs and circles. It exhibits a reflection coefficient of -39 dB over a simulated bandwidth of 340 MHz; it has a gain of 1.04 dB and an efficiency of around 70%. This prototype is fabricated and its S11 is measured to get an operational frequency of 8.08 GHz with same S11 and bandwidth values. The insertion of slots in the antenna design improved its performance to get a higher [Formula: see text] of 8.21 GHz and an improved gain of 2.43 dB. The SAR value of the antenna is found to be around 1.4 W/Kg at a safe separation distance of 60 mm from the breast. As an array, it proved its ability to detect the presence of the tumor, its size and position. This is simply achieved by plotting the propagating E-field that is induced inside the breast. The main advantage of this system lies in the fact that it does not require any long-time complicated image processing. By observing E-field plots, it is seen that the | Ex | decreased from 8.37 V/m to 1.91 V/m. As for the | Ey |, it increased from 2.72 V/m to 4.12 V/m; both comparisons made between healthy and cancerous tissues, respectively. Simulations are conducted in HFSS; the antenna proved to be a good candidate for breast tumor detection, sizing and localization systems.

DDDMOSFET Performance Improvement by Gate Oxide Removal Followed by Silicided Source/Drain Formation in Gate Slots

In this work, the intentional insertion of slots in metal gate (MG) is introduced to solve the dishing issue for the double-diffused drain MOSFET (DDDMOSFET) fabrication. For traditional DDDMOSFET, the gate oxide layer in slots will be reserved to improve the device reliability, which requires an additional photomask to screen the gate/slot regions during the following sidewall formation and source/drain (S/D) implantation. This makes the process more complicated with increased cost. Without that additional photomask, it is proposed that the removal of gate oxide layer in slots can directly allow the floating S/D formation and the followed Ni silicidation there. It is demonstrated that such a novel process can not only relieve the MG dishing issue but can also effectively result in ~16% higher ON current and comparable OFF current for both N- and P-DDDMOSFETs without threshold voltage shift after applying electrical stress on gates. It is also revealed that the floating silicided S/Ds in slots have negligible influence on device breakdown characteristics. By saving one photomask, this work proposes a novel solution for the effective integration of core devices with very small feature sizes and high-voltage (HV) devices with large feature sizes in the same die, which is a common challenge for display driver chip fabrication using high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> /MG (HK/MG) technology.

A Novel Wideband and Multi-band Implantable Antenna Design for Biomedical Telemetry

In this work, a novel multi-tracks wideband and multi-band miniaturized antenna design for implanted medical devices biomedical telemetry is proposed. This antenna entirely covers seven frequency bands which are the bands (401−406) MHz of the Medical Device Radiocommunications Service (MedRadio), the three bands (433.1−434.8), (868.0−868.6), and (902.8−928.0) MHz of the Industrial, Scientific, and Medical (ISM), and the three bands (608−614) MHz, and (1.395−1.400) and (1.427−1.432) GHz of the Wireless Medical Telemetry Service (WMTS). The antenna possesses a compact full size of (19.5 × 12.9 × 0.456) mm3. The antenna miniaturization and impedance bandwidth enhancement are achieved using two techniques: the patch slotting and insertion of open-end slots in the ground plane, respectively. Prototype of proposed antenna with multi-tracks has been fabricated and tested in free space. The comparison between the simulated and measured reflection coefficient has been done and found in good agreement with each other. Furthermore, simulations of the proposed antenna implanted in the underneath the scalp in a realistic human model shows a wideband operation from 0.19 to 0.94 GHz, and from 1.38 to 1.54 GHz corresponding to return loss (S11 ≤ −10 dB). Link budget calculation is performed to specify the range of telemetry considering both Specific Absorption Rate (SAR) restrictions and effective isotropic radiated power (EIRP) limitations. The designed implantable antenna with full ground plane presents an appropriate reflection coefficient for muscle implantation. Furthermore, the designed implanted muscle antenna may be also suitable for skin implantation.

Wideband Three Loop Element Antenna Array for Future 5G mmwave Devices

In this work, a compact, light-weight, low-cost, and easy install and incorporate mmwave printed square loop antenna with a perturbed ground plane is proposed. The antenna is fabricated on an ultra-thin 0.254 mm Rogers RT/Duroid 5880 substrate. The antenna resonates between 26 GHz and 40 GHz providing the broad bandwidth of 13 GHz ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 47$ </tex-math></inline-formula> %). First, a single element consisting of three rectangular square loops and a transmission line with total dimensions of 9 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times11$ </tex-math></inline-formula> mm ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.84\,\,\lambda _{0} \times 1\,\,\lambda _{0}$ </tex-math></inline-formula> ) is designed. The loop elements are arranged on top of each other and with the further insertion of square slot in ground plane, wideband resonance response has been achieved. The antenna demonstrates gain of more than 3.3 dBi, and radiation and a total efficiency of 98% at 28 GHz. The proposed design enables spatial diversity and minimize the effects of interference between adjacent channels by providing dual-beam within desired frequency band. In addition, a linear array ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$18.5\times22.5$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of four elements with a traditional feeding network is also designed, simulated, and measured. The gain of the array is 10.1 dBi, while the radiation and the total efficiency is more than 92 % at 28 GHz. A brief literature review and comparison of this work with other published works is also presented. To validate the proposed design and concept, a prototype is fabricated for both, a single element, and an array. It is found that the measured results and the computed results are in good agreement. Therefore, we believe that this system will find its applications within modern mmwave communication cellular devices.

Thermal-aware Adaptive Platform Management for Heterogeneous Embedded Systems

Recent trends in real-time applications have raised the demand for high-throughput embedded platforms with integrated CPU-GPU based Systems-On-Chip (SoCs). The enhanced performance of such SoCs, however, comes at the cost of increased power consumption, resulting in significant heat dissipation and high on-chip temperatures. The prolonged occurrences of high on-chip temperature can cause accelerated in-circuit ageing, which severely degrades the long-term performance and reliability of the chip. Violation of thermal constraints leads to on-board dynamic thermal management kicking-in, which may result in timing unpredictability for real-time tasks due to transient performance degradation. Recent work in adaptive software design have explored this issue from a control theoretic stand-point, striving for smooth thermal envelopes by tuning the core frequency. Existing techniques do not handle thermal violations for periodic real-time task sets in the presence of dynamic events like change of task periodicity, more so in the context of heterogeneous SoCs with integrated CPU-GPUs. This work presents an OpenCL runtime extension for thermal-aware scheduling of periodic, real-time tasks on heterogeneous multi-core platforms. Our framework mitigates dynamic thermal violations by adaptively tuning task mapping parameters, with the eventual control objective of satisfying both platform-level thermal constraints and task-level deadline constraints. We consider multiple platform-level control actions like task migration, frequency tuning and idle slot insertion as the task mapping parameters. To the best of our knowledge, this is the first work that considers such a variety of task mapping control actions in the context of heterogeneous embedded platforms. We evaluate the proposed framework on an Odroid-XU4 board using OpenCL benchmarks and demonstrate its effectiveness in reducing thermal violations.

Design of Broadband Dual-Polarized Rectenna Array for WPT Applications

A broadband dual-polarized microstrip array antenna designed is proposed. To achieve wide 10 dB bandwidth for broadband operation, the technique of applying a ladder-shaped monopole antenna type with a rectangular slot insertion in the ground plane is implemented. The proposed design showed wide impedance bandwidth of the 1702-2755 MHz (47.2%). In addition, adding an open slot into the rectangular radiating element with an asymmetric ground plane was used and resulted in a slightly displacement of the radiation pattern. The 1 × 2 array type for two ladder-shaped patch array elements are arranged in symmetric feed network. By meticulously arrangement the two array antennas’ positions to achieved good ports isolation, with 10 dB bandwidth for the operating bands in free-space can be achieved. This antenna is used as a rectenna (rectifying antenna), which receives the RF energy of vertical and horizontal polarization wave in free space for 2.4 GHz wireless power transmission. The rectifier circuit setup using two zero biased rectifier and voltage doubler circuit. A matching network designed with small size chip components have a significant improvement in impedance matching and eliminate high order harmonics between the antenna and rectifying circuit. The proposed dual-polarized rectenna provided the RF-to-DC conversion efficiency as high as 78.8% when 14 dBm microwave power was received at 2.4 GHz with a 1 KΩ load.

Tunable circularly polarized graphene antenna for THz applications

A technique is implemented for the generation of tunable circularly polarized THz wave using patterned graphene patch. The aspect ratio of graphene patch is selected to operate with the harmonics at frequency 1.7, 2.23, 3.26 and 3.41 THz covering three bands 1.67 - 1.73, 2.18 - 2.27 and 3.17 - 3.49 THz. The graphene patch is perturbed by inserting a patterned slot to generate the set of orthogonal magnetic dipoles and hence the CP wave. Insertion of slot shifts the resonant frequency of the generated harmonics at 2.95, 3.59, 4.89 and 5.068 THz covering the bands 2.86 - 2.99, 3.54 - 3.66 and 4.83 - 5.12 THz. Also, the dual-band circular polarization is obtained with 3-dB axial ratio bandwidth of 1.68 % (2.94 - 2.99 THz) and 0.4 % (4.99 - 5.01 THz) in the first and third operating band, respectively. Furthermore, the utilization of graphene in the radiator provides the frequency tunability of generated CP wave by varying the chemical potential. The antenna can be utilized in the biomedical applications at THz frequency band.

Dual‐band dielectric resonator antenna with multi‐frequency circular polarisation

A dual-band rectangular dielectric resonator (DR) antenna is implemented with a multi-frequency circularly polarised (CP) response. The wide dual-band response is achieved by inserting the slots in the DR. The insertion of slots in the DR in a specific manner generates the orthogonal degenerate modes. Consequently, the multi-frequency CP response is obtained. The antenna provides the total overlapping CP bandwidth of 4.96% (13.36–14.04 GHz) in the lower band and 3.28% (14.95–15.45 GHz), 9.624% (17.11–18.84 GHz) and 0.517% (19.28–19.38 GHz) in the upper band. The antenna provides the 10 dB impedance bandwidth of 6.44% (13.36–14.25GHz) and 28.89% (14.95–20GHz) in the lower and upper bands, respectively. The peak gain of antenna remains >3 dBic in the passbands.

Flexible ultra-wideband rectangle monopole antenna with O-slot insertion design

Slot insertion design has proven to be an effective method to increase the bandwidth in the design of microstrip antenna. In this paper, the slot insertion design is applied to the flexible ultra-wideband (UWB) antenna. A flexible rectangular UWB monopole antenna is proposed and fabricated with O-slot design using the transfer printing method. By simulating the influence of O-slot design parameters on electromagnetic performance of the antenna, an optimized antenna design is obtained to keep the reflection coefficient under $-$10 dB with the frequencies ranging from 3.5 to 17.8 GHz when the antenna is bent with curvature radius as small as 11 mm. The effect of bending on the reflection coefficient is analyzed. Mechanical simulations indicate that the existence of O-slot can reduce the strain concentration on the metal layer of antenna, which enhances the flexibility of the antenna.

Body Antenna With DGS for Body Centric Wireless Communication System

This paper presents modified patch antenna for 3 GHz and 5 GHz operating frequencies. Here different approaches are studied by varying slot sizes, defected ground size, notch and also changing feed position. Insertion of slots gives dual frequency operation. Notch provides shifting of lower frequency band towards left hand side. Here combined effect of each techniques adopted gives desired result. Proposed antenna resonates for 3 and 5 GHz frequency. Simulation is done using IE3D software for various parameters. Return loss of final design was -12.17 dB for 3 GHz frequency and VSWR of 1.65. For 5 GHz simulation response was -10.04dB return loss and VSWR of 1.91. Proposed antenna is fabricated giving different details. Paper gives good agreement between measured and simulated results.

Development of high gain multiband antenna with centre‐offset copper strip‐based periodic structure

ABSTRACTIn this article, two coplanar waveguide‐fed high gain multiband antennas with and without uniplanar copper strip‐based electromagnetic band gap (CS‐EBG) structure are proposed for portable wireless applications at 2.1, 2.4, 3.5, 5.2, 5.4, and 5.8 GHz. The initial multiband antenna is realized by patch‐ground shape modification and open‐ended rectangular slot insertion on the patch. The two layer uniplanar CS‐EBG structure is composed of square ring periodic elements of copper strips of different widths and gaps. The top unit cells are placed at an offset position with respect to the bottom layer, which is new technique applied to obtain multiple resonances from such a simple and compact planar structure. The antenna, when combined with the CS‐EBG structure, still preserved its multiband characteristics and produced directional pattern because of the reflecting property (like artificial magnetic conductor, AMC) of the CS‐EBG/AMC structure behind it, which was donut and omnidirectional shape in case of the antenna alone. The initial antenna gain is 5 dBi while the final antenna gain is improved to approximately 12 dBi at the first band and more than 6 dBi at other bands. Thus, the developed square ring copper strip structure is very effective to improve the antenna performances and finally resulted in a high gain antenna. Both of the configurations with and without the CS‐EBG/AMC are fabricated and tested, and the measurements are well agreed with the simulations. Despite of the slight frequency shifting, the antenna is still suitable for the portable wireless operation such as Wi‐Fi, WiMax, WLAN/HIPERLAN and even for LTE/4G technology at some frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1608–1614, 2015

Impact of the Electronic Architecture of Optical Slot Switching Nodes on Latency in Ring Networks

Optical slot switching has formerly been proposed as a flexible solution for metropolitan ring networks to carry data traffic with a subwavelength switching granularity and with good energy efficiency, which is enabled by optical transparency. In this paper, we propose for the first time, to the best of our knowledge, several architectures for the electronic side of optical slot switching nodes to increase flexibility through the addition of electronic switches, working either at client packet granularity or at slot granularity. Such electronic switches can be located at either the transmitter side or receiver side, or at both sides of a node, thereby decreasing traffic latency, at the expense of increased node cost and/or energy consumption. This paper focuses on the latency aspect. We investigate the impact of a timer that can be used to upper bound the slot insertion time on the medium. We also propose a novel client packet queuing model in an optical slot switching ring and assess and compare the latency of these node architectures analytically and with simulations.

Manufacturing technology for continuous high-density coils for brushless motors

This paper reports on our development of a manufacturing technology for continuous high-density coils and terminal processing for high performance motor stators. We have developed a “series winding and collective forming method”. The coils are wound in series, and their slot insertion parts are collectively formed and clung. Four continuous and high-density coils with a slot-fill rate of 75% were prepared using the developed winding form and manufacturing facilities. Moreover, terminal insulation of the continuous coils was established with the developed wiring board. A 60% decrease in man-hours and 95% decrease in the cost of the board can be expected by using our technique rather than conventional printed circuit board manufacturing techniques.

Size reduction of planar patch antenna by means of slot insertion

The present note concerns the reduction of the global size of a planar patch antenna by using the insertion of slots and other capacitive effects. The method of optimizing the size is shown to obtain the best reduction for the patch. Two examples are shown for the S-frequency band with linear polarization, including a single substrate and a double substrate. The configuration is reduced by 20% in dimensions on a substrate of permittivity of 2–6.15. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 111–113, 2000.