The paper presents a new practical design for a 4 × 1 planar switched array of dielectric filled waveguide antennas loaded with bow‐tie shaped slots operating at 26.5 to 29.5 GHz for 5G ...millimetre‐wave applications. The design is realized as a three‐layered architecture, with the top layer behaving as a radiator, the bottom layer as a feed network and a control circuit; and a common ground plane in the middle layer, offering a small form factor. The bow‐tie slots are used to achieve suitable bandwidth with a stable gain of ∼ 13 dBi. The proposed dielectric filled waveguide (DFW) is shown to offer a 5 deg/GHz freq.‐controlled beam‐sweep and a 70° fixed freq. beam‐steer. With only three switching ICs, it offers low power consumption and fast beam‐steering. Further, a combination of freq.‐controlled beam‐scanning and fixed‐freq. beam‐steering allows for a wide coverage of the antenna.
This paper presents a new practical design for a 4 × 1 planar switched array of dielectric filled waveguide antennas loaded with bow‐tie‐shaped slots operating at 26.5 to 29.5 GHz for 5G millimetre‐wave applications.
Abstract
This letter presents a new thin substrate‐integrated waveguide with twisted integrated–digitated capacitor‐based corrugations that offers a transmission loss < 0.55 dB. The presented ...waveguide operates at TE
10
mode and is used to present a wideband beam‐scanning leaky‐wave antenna with an array of dumbbell‐shaped slots. The antenna is shown to operate at a frequency band of 25–37 GHz and offers a gain > 13 dBi throughout the frequency band. It has a frequency‐dependent beam‐scanning capability of 6 deg/GHz. The proposed antenna being thin is extremely conformal and is suitable for applications in millimetre‐wave off‐body communication.
A fast beam‐steering capability has been demonstrated using an array of high‐gain corrugated substrate integrated waveguide (CSIW) slot antennas coupled with a bespoke dielectric lens. The proposed ...system prototype has been simulated, fabricated, and measured. The proposed system is shown to have a full 360° beam‐steer in azimuth plane with an angular sensitivity of 9°, half power beamwidth (HPBW) of 18° and a gain of < 20.5 dBi at n257 frequency band of 26 to 29 GHz. Further, the antenna is shown to have a fixed frequency beam steer of ±15° along with a frequency‐controlled beam‐scanning of ±45° in the elevation plane. The antenna setup is shown to be suitable for applications for 5G base‐stations.
The article presents an array of leaky wave antenna coupled with bespoke lens that offer a 360° beam‐steer in the azimuthal plane and 30° beam‐steer in the elevation plane at 28 GHz for 5G base‐stations.
A novel methodology is introduced for designing bespoke homogeneous and graded index lenses for enhancing the gain of travelling wave antenna arrays (TWAs). 3D-printed lenses in the literature are ...majorly explored with standing wave antennas (SWAs) such as a microstrip or a horn antenna for gain enhancement. As there is progressively less power radiated from each slot in a TWA, as well as the successive phase delay between slots, the existing lens design approaches used for SWAs is not optimal for TWAs. Accordingly, we present a new approach of introducing a curvature to the lens that is derived from studying the power radiation profile of each slot of the TWA. This new methodology is demonstrated on a dielectric filled waveguide (DFW) slot array antenna operating at 26 -30 GHz band. An optimized dielectric graded lens and an optimized homogeneous lens have both been designed, fabricated, and measured with the DFW slot array. The new lens demonstrated a gain enhancement of more than 7 dB compared to less than 4 dB with conventional dielectric lenses. The proposed lens theory has been further verified with a bespoke optimized lens for a periodic stub-loaded microstrip leaky-wave antenna with a beam-scanning of 65∘. Design rules are included that can be applied for any TWA.
Indian Railways boasts as the superior modes of transportation in the country and it functions in all rural and urban networks including narrow, meter and broad gauges. Railway accidents due to ...mechanical failure of wheels are still considered with primary importance by research and development wing. Studies have revealed that the braking of tread zone of wheel results in non-uniform heating and creates severe stresses in railroad car wheels. The existing trend towards high speed trains and larger axle loads has created a need for a better understanding of the technology involved in designing of wheel. All the types of trains including freight and passenger, are generally braked using cast iron brake blocks which adds to the thermal loading on the wheel. Braking application for long time results in high temperatures on the wheel tread and the rim. Thermal loading has sufficient capability to not only initiate cracks but also increases the crack growth rate.
Virtual Assistant technology is rapidly proliferating to improve productivity in a variety of tasks. While several virtual assistants for everyday tasks are well-known (e.g., Siri, Cortana, Alexa), ...assistants for specialty tasks such as software engineering are rarer. One key reason software engineering assistants are rare is that very few experimental datasets are available and suitable for training the AI that is the bedrock of current virtual assistants. In this paper, we present a set of Wizard of Oz experiments that we designed to build a dataset for creating a virtual assistant. Our target is a hypothetical virtual assistant for helping programmers use APIs. In our experiments, we recruited 30 professional programmers to complete programming tasks using two APIs. The programmers interacted with a simulated virtual assistant for help the programmers were not aware that the assistant was actually operated by human experts. We then annotated the dialogue acts in the corpus along four dimensions: illocutionary intent, API information type(s), backward-facing function, and traceability to specific API components. We observed a diverse range of interactions that will facilitate the development of dialogue strategies for virtual assistants for API usage.
Source code summarization is the task of writing natural language descriptions of source code. A typical use case is generating short summaries of subroutines for use in API documentation. The heart ...of almost all current research into code summarization is the encoder–decoder neural architecture, and the encoder input is almost always a single subroutine or other short code snippet. The problem with this setup is that the information needed to describe the code is often not present in the code itself—that information often resides in other nearby code. In this paper, we revisit the idea of “file context” for code summarization. File context is the idea of encoding select information from other subroutines in the same file. We propose a novel modification of the Transformer architecture that is purpose-built to encode file context and demonstrate its improvement over several baselines. We find that file context helps on a subset of challenging examples where traditional approaches struggle.
Source code summarization is the task of writing natural language descriptions of source code. The primary use of these descriptions is in documentation for programmers. Automatic generation of these ...descriptions is a high value research target due to the time cost to programmers of writing these descriptions themselves. In recent years, a confluence of software engineering and artificial intelligence research has made inroads into automatic source code summarization through applications of neural models of that source code. However, an Achilles' heel to a vast majority of approaches is that they tend to rely solely on the context provided by the source code being summarized. But empirical studies in program comprehension are quite clear that the information needed to describe code much more often resides in the context in the form of Function Call Graph surrounding that code. In this paper, we present a technique for encoding this call graph context for neural models of code summarization. We implement our approach as a supplement to existing approaches, and show statistically significant improvement over existing approaches. In a human study with 20 programmers, we show that programmers perceive generated summaries to generally be as accurate, readable, and concise as human-written summaries.
This letter presents a novel circular leaky-wave antenna (CLWA) on a half-mode inter-digitated capacitor based corrugated substrate integrated waveguide (HM-IDC-CSIW) to produce a beam-scanning ...orbital angular momentum (OAM) wave. Longitudinal radiating slots in a conventional LWA have been translated into an arc-shaped slot for this CLWA. An array of arc-shaped slots is then used to produce OAM mode 1 from 17 to 21 GHz, while producing a beam-scanning of ± 30° in the azimuth plane. The measured results of the antenna confirm a gain of 12-14.2 dBi throughout the frequency band while maintaining an efficiency >70% and a high OAM mode purity. Such OAM-based antennas with frequency-controlled beam-scanning can be used for secure communications and to create imaging systems that can sense in different directions simultaneously.
Source Code Summarization is a program comprehension task that consists of writing natural language descriptions of source code. These summaries are important because they are an essential part of ...software documentation, such as the descriptions in APIs. They are also necessary for maintenance of legacy soft- ware systems. The state-of-the-art for automatic source code summarization, when I started my work were neural networks developed for machine translation. They were designed to accept a snippet of source code, usually a subroutine, as a sequence of tokens and generate an English language description. These techniques were based on sequence-to-sequence learning , i.e., the summary sequence was built one word at a time, using an attention mechanism and code sequence. However, often some of the information required to summarize the subroutine descriptively is not inside the subroutine. The necessary information lives in the ”context” around the code, such as other subroutines, files, and build files, as well as the pre-learnt human knowledge. In this dissertation, I will present my research on modeling various types of contextual information for better automatic source code summarization.
PDF
