On the extension of commercial planar circuit CAD packages to the analysis of two‐port waveguide components

We introduce a simple algorithm that enables several commercial codes, based on the method of moments (MoM) and developed for the analysis of planar structures, to address the analysis of a class of two‐port waveguide components. Its key step is a numerical calibration that can be easily automated. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 113–117, 2003.     

Optimization-oriented design of free-running and tunable microwave oscillators by fully nonlinear CAD techniques (invited article)

The article reviews the application of optimization techniques, in conjunction with the methods of harmonic-balance simulation, to the nonlinear design of free-running and tunable microwave oscillators. The purpose is to give an in-depth treatment of many different aspects of the practical oscillator design problem, and of their formulation in terms of numerical optimization. This includes free-running and tunable oscillators, with both discrete (multiple-cavity) and continuous tuning. Conventional specifications on electrical performance are extended to include near-carrier phase noise, steady-state stability, and tuning linearity in the VCO case. The problem of designing oscillators integrated with other nonlinear subsystems to build up multifunctional modules is also addressed. Several examples of application to typical engineering problems are provided. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 52–74, 1997.     

Personal computer-based direct synthesis of optimum rectangular waveguide E-, H-, and EH-plane transformers

In this work a direct synthesis technique is presented for the optimum design of rectangular waveguide continuous and stepped impedance transformers. The synthesis technique is based on a generalized Fourier transform pair and it is implemented on a 486 DX2 machine. Unlike the conventional techniques, the proposed method is exact and does not rely on repeated analysis-based computer optimization that requires a large computer memory and speed. The proposed method requires less than a second to design a Chebyshev EH-plane transformer. The validity of the method has been shown by the design and analysis of several E-, H-, and EH-plane rectangular waveguide Ka-band transformers. The analysis subroutines were verified using published experimental results. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7 : 289–308, 1997.     

A novel full‐wave CAD for the design of tapered leaky‐wave antennas in hybrid waveguide printed‐circuit technology

This work presents a novel computer‐aided design (CAD) tool for the design of tapered leaky‐wave antennas (LWAs) in hybrid waveguide printed‐circuit technology. The software package is composed of several tools, which are connected together to provide a semi‐automated step‐by‐step design procedure. The design procedure is presented and the different tools are described, together with the involved theory, leading to the design of tapered LWAs. A practical taper design is performed, and comparisons with simulations using commercial software (HFSS) are presented for validation purposes. Due to the full‐wave nature of the technique used in the analysis engine, excellent agreement is shown between the proposed 2D‐based approach, and 3D HFSS results. Also, the analysis procedure is fast, thus leading to semi‐automated designs that are not affordable with common 3D optimization techniques. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Hybrid method of analysis of slot discontinuity in a rectangular waveguide and the validity of circuit representation

A novel analysis to compute the admittance characteristics of the slots cut in the narrow wall of a rectangular waveguide (also called edge slot) is presented. The slot aperture field is expanded in terms of entire domain sinusoidal basis functions and is solved using Galerkin's method. The computed results have been compared with the measured data published in the previous literature to validate the present analysis. The validity of representing the edge slot as a shunt element is examined and an alternate way of representing the edge slot is suggested as being more accurate. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 339–349, 1998.     

Information technology (IT) in Saudi Arabia: Culture and the acceptance and use of IT

The unified theory of acceptance and use of technology (UTAUT), a model of the user acceptance of IT, synthesizes elements from several prevailing user acceptance models. It has been credited with explaining a larger proportion of the variance of ‘intention to use’ and ‘usage behavior’ than do preceding models. However, it has not been validated in non-Western cultures. Using a survey sample collected from 722 knowledge workers using desktop computer applications on a voluntary basis in Saudi Arabia, we examined the relative power of a modified version of UTAUT in determining ‘intention to use’ and ‘usage behavior’. We found that the model explained 39.1% of intention to use variance, and 42.1% of usage variance. In addition, drawing on the theory of cultural dimensions, we hypothesized and tested the similarities and differences between the North American and Saudi validations of UTAUT in terms of cultural differences that affected the organizational acceptance of IT in the two societies.     

Theory of planning behavior (TPB) and customer satisfaction in the continued use of e-service: An integrated model

This study has devoted much effort to developing an integrated model designed to predict and explain an individual’s continued use of online services based on the concepts of the expectation disconfirmation model and the theory of planned behavior. Empirical data was collected from a field survey of Cyber University System (CUS) users to verify the fit of the hypothetical model. The measurement model indicates the theoretical constructs have adequate reliability and validity while the structured equation model is illustrated as having a high model fit for empirical data. Study’s findings show that a customer’s behavioral intention towards e-service continuance is mainly determined by customer satisfaction and additionally affected by perceived usefulness and subjective norm. Generally speaking, the integrated model can fully reflect the spirit of the expectation disconfirmation model and take advantage of planned behavior theory. After consideration of the impact of systemic features, personal characteristics, and social influence on customer behavior, the integrated model had a better explanatory advantage than other EDM-based models proposed in prior research.     

Interacting Socially with the Internet of Things (IoT): Effects of Source Attribution and Specialization in Human–IoT Interaction

This study investigates the theoretical mechanisms by which the variations in source attribution (multiple sources vs. single source) and specialization (multifunctionality vs. single functionality) of Internet of Things (IoT) devices influence the quality of human–IoT interaction. Results from a between‐subjects experiment (N = 100) indicate that IoT devices that elicit the sense of multiple agencies and are specialized in a single function induce greater social presence and perceived expertise, which, in turn, lead individuals to show a more positive attitude toward the devices and to ascribe greater quality to the information transmitted by them. The results also reveal that the effect of multiple source attribution is more pronounced for individuals for whom the content of the information has low personal relevance.