bandpass filters with the optimal 2D and 3D design parameters. It can be seen the response accuracy for both filters is good according to the design specifications and the error criterion. By applying the proposed technique to several second-order structures, the coupling coefficients of higher order filters can be efficiently obtained for the design of more complex microwave filter [14]. CONCLUSIONA linear iterated prediction 2D to 3D SM optimization algorithm is presented. The key idea is to reduce the number of analysis needed with time consuming 3D electromagnetic simulators, by performing optimization with fast 2D simulators, and a proper mapping between the two spaces. The application of this technique to the optimization of 2D to 3D first-order and second-order evanescent rectangular waveguide bandpass filters with dielectric posts has needed only a few iterations until the required convergence is reached, therefore leading to a reduced computational cost. This procedure can compete against other "state of the art" optimization procedures. Moreover, it does not require complex mathematical knowledge and tools, and therefore, it can be easily integrated in CAD environments with 2D and 3D circuit structure EM analysis. Consequently, it can also be easily used by circuits and systems designers.

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This article shows a new quasi‐fractal microstrip patch antenna using the Minkowski curve at the radiant and nonradiant margin of this device. The structures analyzed were initially designed using the Ansoft Designer™ software that implements the method of moments. Some antenna prototypes were built and measured. The use of the inset‐fed technique enables a good impedance matching, as can be confirmed by the low return loss obtained (<−25 dB) at the resonance frequencies. Antennas designed using the Minkowski curve presented a reduction of up to 42% when compared with a conventional inset‐fed rectangular patch. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:805–809, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25071

0.92 and 0.85, respectively. The transmitted pulse undergoes very minimum distortion. Hence the received signal fairly retains the input pulse shape. CONCLUSIONIn this letter, a CPW-fed compact UWB antenna with tunable band-notched characteristic using a single kg/4 stub loaded with varactor diode has been successfully studied and fabricated. The proposed antennas have excellent impedance bandwidth covering the targeted UWB band. The notched bandwidth is narrow, highly selective, and continuous tunable with applied bias voltage to the varactor diode. The measured radiation pattern of the antenna is stable and consistent with frequency with fairly omnidirectional pattern in broadside plane. The system transfer function, group delay, ringing duration, and the SFF of the bandnotched UWB antenna system in face to face as well as side by side orientations are measured and discussed. The measured values indicate that the proposed band-notched UWB antenna show minimum pulse distortion and find suitable for potential application in UWB systems.

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