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In this paper, we review recent advances in evolutionary programming (EP) and its implementation in various antenna, microwave, frequency selective surfaces and RF circuit optimization problems. EP, unlike the other two paradigms of evolutionary computational techniques, namely, genetic algorithms (GA) and evolution strategies (ES), uses a mutation only variation operator where adaptive and/or self-adaptive techniques exist, or can easily be designed, for adapting the parameters of mutation operator during the evolution process. We present the so-called meta-EP and design of its mutation operator, using Gaussian, Cauchy and Poisson mutations as well as a hybrid of these mutations, for continuous, discrete and mixed parameter electromagnetic optimization problems. In addition, an efficient hybrid use of EP, gradient search methods and cluster analysis, as well as a novel hybrid EP-GA algorithm are discussed. Examples presented include optimizations of corrugated horn antennas, multilayered stacked microstrip antennas, Yagi-Uda arrays, partially reflective surfaces, dielectric filters, meander-line polarizer and RF duplexers [ABSTRACT FROM PUBLISHER]

A set of closed-form Green's functions is used in a mixed-potential integral-equation technique for the efficient modeling of planar microstrip structures of arbitrary shape on an electrically thin substrate. Various MMIC and microstrip antenna structures are simulated. It is shown that excellent accuracy at a substantial reduction in total simulation time is achieved for a wide range of frequencies and substrate parameters. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 342–345, 1999. [ABSTRACT FROM AUTHOR]

The feasibility of obtaining high gain from a class of “Yagi-like” multilayer printed stacked dipole arrays is investigated. A moment-method approach is used to numerically model the array structure. Numerical results for the case of a three-layer stacked microstrip Yagi are presented. It is shown that the use of Yagi-like parasitic director elements can result in a gain of 10 dBi or higher without the need for a high-permittivity superstrate layer. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 317–321, 1998. [ABSTRACT FROM AUTHOR]

The fundamental radiation characteristics of a microstrip antenna on a cylindrical substrate with a thick cover layer is investigated by using a magnetic line source model. Numerical results for the radiation pattern and conductance are presented. It is found that certain combinations of curvature radius and cover-layer thickness could result in significant distortions in the pattern. Lossy dielectric material may be used to reduce these undesired effects. [ABSTRACT FROM AUTHOR]

Investigates the radiation performance of rectangular microstrip patch antennas on two ceramic substrates, barium-titanate and neodymium-titanate. Radiation patterns; Effect of reducing the ground plane size on radiation patterns, cross-pol levels and resonant frequency of the patch antennas.