scholarly journals On the applicability of numerical tools for simulating wave-ports close to the cutoff frequency

Author(s):  
Eman Mohamed Eldesouki ◽  
Khalid Mustafa Ibrahim ◽  
Ahmed Mohmed Attiya

This paper focuses on a common drawback in electromagnetic numerical computer aided design computer aided design (CAD) tools: high frequency structure simulator (HFSS), computer simulation technology (CST) and FEKO, where the excitation by using a wave-port below and close to the cutoff frequency has unreliable values for the reflection coefficient. An example for such problem is presented in the design of a dual horn antenna fed by two different waveguide sections. To overcome this numerical error in the results of these CAD tools, a tapered waveguide section is used in the simulation as an excitation mechanism to the feeding waveguide. The cross section of the input port at this tapered waveguide section is designed to have a cutoff frequency smaller than the lowest frequency under investigation for the original problem. Then, by extracting the effect of the tapered section from the obtained reflection coefficient, it would be possible to obtain the reflection coefficient of the original problem.

2021 ◽  
pp. 97-110
Author(s):  
V.V. Batrakov ◽  
A.I. Krylov ◽  
V.N. Saev ◽  
B.N. Nefyodov ◽  
V.M. Novichkov ◽  
...  

The paper presents space simulators (SS), types of instrumentation equipment installed on the workplaces of the space simulators operators (SSOPW), multi-functional display panel (MFDP), computer-aided design (CAD) tools, 3D printing technologies.


Author(s):  
Jeff Heisserman ◽  
Raju Mattikalli

Abstract Computer aided design tools are gaining popularity in industry due to their ability to model the geometric aspects of products. This has shown substantial benefit for reducing the need and expense of building physical prototypes and allowing parts and tooling to be manufactured directly from these models. However, the current capabilities in existing CAD tools for modeling assemblies are quite limited. In this paper we introduce a representation for describing interfaces between parts within hierarchical assemblies for capturing functional and physical mating relations. This representation is designed to support automated reasoning and automated generation and modification of assemblies. It is also designed for use with very large assemblies, compactly representing the interfaces of parts and assemblies that are reused within larger assemblies. We describe how this representation is used in our prototype design system, Genesis, for designing aircraft systems.


Author(s):  
David Veisz ◽  
Essam Z. Namouz ◽  
Shraddha Joshi ◽  
Joshua D Summers

AbstractThis paper presents a preliminary comparison between the role of computer-aided design (CAD) and sketching in engineering through a case study of a senior design project and interviews with industry and academia. The design team consisted of four senior level mechanical engineering students each with less than 1 year of professional experience are observed while completing an industry sponsored mechanical engineering capstone design project across a 17 week semester. Factors investigated include what CAD tools are used, when in the design process they are implemented, the justification for their use from the students' perspectives, the actual knowledge gained from their use, the impact on the final designed artifact, and the contributions of any sketches generated. At each design step, comparisons are made between CAD and sketching. The students implemented CAD tools at the onset of the project, generally failing to realize gains in design efficiency or effectiveness in the early conceptual phases of the design process. As the design became more concrete, the team was able to recognize clear gains in both efficiency and effectiveness through the use of computer assisted design programs. This study is augmented by interviews with novice and experienced industry users and academic instructors to align the trends observed in the case study with industry practice and educational emphasis. A disconnect in the perceived capability of CAD tools was found between novice and experienced user groups. Opinions on the importance of sketching skills differed between novice educators and novice industry professionals, suggesting that there is a change of opinion as to the importance of sketching formed when recent graduates transition from academia to industry. The results suggest that there is a need to emphasize the importance of sketching and a deeper understanding as to the true utility of CAD tools at each stage of the design process.


2008 ◽  
Vol 17 (03) ◽  
pp. 399-421 ◽  
Author(s):  
RANJITH KUMAR ◽  
ZHIYU LIU ◽  
VOLKAN KURSUN

Computer-aided design (CAD) tools are frequently employed to verify the design objectives before the fabrication of an integrated circuit. An important circuit parameter that requires accurate characterization is the power consumption due to the strict constraints on the acceptable power envelope of integrated systems. Circuit simulators typically provide built-in functions to measure the power consumption. However, the accuracy of the measured power is mostly overlooked since the approximations and the methodologies used by the existing built-in power estimation tools are not well documented. The research community tends to assume that the built-in functions provide accurate power figures. This blind-trust in the CAD tools, however, may lead to gross errors in power estimation. A generic methodology to accurately measure the power and energy consumption with the circuit simulators is described in this paper. An equation to calculate the device power consumption based on the different current conduction paths in a MOSFET is presented. An expression for the total power consumption of a complex circuit is derived by explicitly considering the different circuit terminals including the inputs, the outputs, and the body-contacts. Results indicate that the power measurements with the built-in functions of widely used commercial circuit simulators can introduce significant errors in a 65 nm CMOS technology. For deeply scaled nano-CMOS circuits, a conscious power and energy measurement with the proposed explicit methodology is recommended for an accurate pre-fabrication circuit characterization.


Author(s):  
Eneko Solaberrieta ◽  
Xabier Amezua ◽  
Xabier Garikano ◽  
Mikel Iturrate ◽  
Jose Antonio Oriozabala ◽  
...  

AbstractIn this paper, due to the importance of maintaining a secure grip with the control hand in kayaking, a simple three phase process is presented for the massive development of personalized grips which allow the improvement of this handgrip. This process consists of obtaining the 3D geometry of the paddler's handgrip by using Reverse Engineering (RE) tools, designing the grip from the obtained 3D geometry by using Computer Aided Design (CAD) tools and manufacturing the grip by using Additive Manufacturing (AM) tools. Therefore, this paper shows that the RE, CAD and AM tools available today allow the customization of products for many applications.


1989 ◽  
Vol 26 (1-2) ◽  
pp. 23-29 ◽  
Author(s):  
Rosemary A. Cobley

The impact made by professional electronic CAD tools and engineering workstations, upon undergraduate courses in the department, is outlined. Student groups have successfully designed, simulated and tested digital systems, which had been implemented as gate arrays. The interest throughout the department has highlighted areas for integrated mechanical/electronic projects.


2020 ◽  
pp. 002205742097959
Author(s):  
Ali Bokhari

Computer-aided design (CAD) tools are widely used in the urban planning process, giving planners the ability to generate urban contexts and many scenarios for future development. However, debate is ongoing regarding the effects of CAD tools on student learning and the reliability of the cluster of assumptions that usually come with them. This article aims to examine whether CityCAD can be an effective tool for achieving learning objectives related to critical thinking, problem-solving, and creativity in the urban planning discipline. This research also examines whether the software influences students’ interest in planning and affects students’ perceptions of the discipline. Using instructor observations, students’ projects, and surveys, we find that using CityCAD in education can achieve learning objectives, increase students’ interest, and enhance the perception of planning as a more creative field. The results have implications for instruction, student recruitment, and perceptions of the field.


Author(s):  
Raluca-Cristina Presura ◽  
Camelia Stoica ◽  
Livia-Andreea Dina ◽  
Relu Aipu ◽  
Petre-Marian Nicolae ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document