International Journal of Rf and Microwave Computer-aided Engineering 

About: International Journal of Rf and Microwave Computer-aided Engineering is an academic journal published by Wiley-Blackwell. The journal publishes majorly in the area(s): Antenna (radio) & Wideband. It has an ISSN identifier of 1099-047X. Over the lifetime, 3691 publications have been published receiving 27469 citations. The journal is also known as: RF and microwave computer-aided engineering.

A review of artificial neural networks applications in microwave computer‐aided design (invited article)

Abstract: Neural networks found significant applications in microwave CAD. In this paper, after providing a brief description of neural networks employed so far in this context, we illustrate some of their most significant applications and typical issues arising in practical implementation. We also summarize current research tendencies and introduce use of self-organizing maps enhancing model accuracy and applicability. We conclude considering some future developments and exciting perspectives opened from use of neural networks in microwave CAD. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 158–174, 1999.

RF MEMS‐based tunable filters

Abstract: This paper overviews the application of RF MEMS switches in tunable filters as well as circuit developments for bandpass filters covering 110 MHz to 2.8 GHz. RF MEMS have several desirable features, including small size, low power requirements, and low loss. The basic operation of Raytheon's RF MEMS capacitive membrane switch is described. An overview of the technique used to integrate the switch into a variable capacitor structure with sixteen capacitance states is provided. Variable capacitor structures are used to construct multipole lumped bandpass filter designs, each with sixteen states. Finally, measured data from two representative five- and six-pole bandpass filters are presented. Characterization data demonstrates that the insertion loss for the five-pole filter using on-chip inductors was between 6.6 and 7.3 dB, and between 3.7 and 4.2 dB for the six-pole filter using off-chip inductors. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE11: 276-284, 2001.

RF MEMs variable capacitors for tunable filters

Abstract: () ABSTRACT: An RF MEMs microelectromechanical system variable capacitor has been demonstrated with a 22:1 tuning range, tuning from 1.5 to 33.2 pF of capacitance. This capacitor was constructed using bistable MEMs membrane capacitors with individual tuning ranges of 70:1 to 100:1, control voltages in the 30-55 V range, switching speeds less than 10 mS, and operating frequencies as high as 40 GHz. These devices may eventually provide a viable alternative to electronic varactors with improved tuning range and lower loss. Q 1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 362)374, 1999.

Fast simulation-driven antenna design using response-feature surrogates

Abstract: In this article, a computationally efficient procedure for electromagnetic EM-simulation-driven design of antennas is presented. Our methodology is based on local approximation models of the antenna response, established using a set of suitably selected characteristic features rather than the entire response such as reflection versus frequency. The approximation model is utilized to verify the level of satisfying/violating given performance requirements, and to guide the optimization process towards a better design. By exploiting the fact that the dependence of the response features on the designable parameters of the antenna of interest is simple close to linear or quadratic, the feature-based optimization converges faster than conventional optimization of frequency-based EM-simulated responses. In order to further speed up the design, coarse-discretization simulations are utilized to estimate the feature gradients with respect to adjustable parameters of the problem at hand. The optimization algorithm is embedded in the trust-region framework for safeguarding convergence. The proposed technique is demonstrated using two antenna examples. In both the cases, the optimum design is obtained at the computational cost corresponding to a few high-fidelity EM antenna simulations. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:394-402, 2015.

On the class‐F power amplifier design

Abstract: Power-amplifier class-F operation is investigated and revised, evidencing the fundamental importance of the harmonic-generating mechanism and the limitations imposed by the device input and output nonlinearities on the ideal class-F behavior. Closed-form expressions are derived for the major design quantities, together with the optimum fundamental and third-harmonic loading of the active device. A design procedure, making use of the derived expressions, is presented and the deviations from the ideal behavior are discussed. Sample designs, making use of a full nonlinear device model and commercial analysis software, are carried out to demonstrate the effectiveness of the analysis and the design procedure. It is shown, both analytically and using commercial nonlinear simulations, that blind application of commonly used, idealized class-F harmonic terminations can cause unexpected detrimental results. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 129–149, 1999