Elder Eldervitch Carneiro de Oliveira

Small size quasi-fractal microstrip antenna M1 EBG-GP

A new patch antenna using the Minkowski fractal curve and Electromagnetic Bandgap structure on plane ground is proposed. The design was based on HFSS and a prototype was built and measured in order to validate the numerical results. A better impedance matching for the device was obtained using the inset-fed technique. The measured return loss for the proposed antenna at the resonant frequency is lower than �15 dB. The M1 EBG-GP antenna resonant frequency is lower than that of a corresponding rectangular inset-fed patch antenna. This results in a reduction of 35.6% for this antenna resonating at 2.45 GHz (ISM band).

A new compact koch fractal patch antenna on an EBG ground plane

A new antenna with Koch fractal patch elements of the first level (KR1) and electromagnetic bandgap in the ground plane (EBG-GP) is proposed in this paper. The design is based on Ansoft HFSSTM software and in order to validate the model several prototypes are built and measured. A better impedance matching for the device is obtained using the inset-fed technique. The measured return loss values for the proposed antennas at the resonant frequencies are lower than -20 dB. The KR1 EBG-GP antennas show corresponding resonant frequencies values lower than the rectangular patch antennas with inset-fed. That results in a size reduction factor around 28% for these structures resonating at 2.45 GHz.

Optimization of the input impedance of Koch triangular quasi-fractal antennas using genetic algorithms

This work presents an optimization on the input impedance of Koch triangular quasi-fractal antennas using an efficient genetic algorithm (GA). The impedance matching is done by using an inset-fed, which is optimized to minimize the return loss (RL). The excitation of this structure is done using a microstrip line. The antennas are designed using the Ansoft Design™ software and the new structures, that are optimized with GA, are simulated, measured and compared with the same patch antenna but with the lengths of the inset-fed (y0) calculated by well-known models available in the literature. The return loss value of the GA optimized antenna is below -40 dB at the resonant frequency.

Using a multilayer perceptrons for accurate modeling of quasi-fractal patch antennas

A multilayer perceptrons (MLP) artificial neural network (ANN) with one hidden layer and trained through the efficient resilient backpropagation (RPROP) algorithm is used for modeling quasi-fractal patch antennas. The design of the proposed antenna is based on the application of rectangular Koch fractal curve to the edges of a conventional microstrip inset-fed patch antenna. The electromagnetic (EM) characterization of the patch antennas was performed using the Ansoft DesignerTM software that uses the method of moments. A parametric analysis was developed as function of the dielectric substrate thickness and size of the quasi-fractal patch antennas. Considering the region of interest of the design parameters a representative EM-dataset was obtained to develop the MLP network model using the conventional EM-ANN neuromodeling technique. The MLP model is able to estimates the behavior of the antennas with very good accuracy and low computational cost. Good agreement is observed between simulated and measured results.

Quasi-fractal Koch triangular antenna

A quasi-fractal Koch triangular antenna is presented in this paper. The antennas were designed using the Ansoft Designer™ software and prototypes were built. The impedance matching of the quasi-fractal antennas is obtained using inset fed lines. Measured values of the return loss for all the build antennas were lower than − 25 dB at the resonant frequency. The proposed antennas are 28.6% smaller in size than a conventional rectangular inset-fed patch. The quasi-fractal contours did not change the radiation pattern at H-plane.

Optimization of the input impedance of Koch Pre-Fractals antennas with genetic algorithms

This work presents an optimization on the input impedance of Koch Pre-fractals patches antennas using an efficient genetic algorithm (GA). The impedance matching is done by recesses (inset-fed), which is optimized to minimize the return loss (RL). The excitation of this structure is done using a microstrip line (L0). The antennas are designed using the package Ansoft Design™ software and the new structures optimized with GA are simulated, measured and compared with the same patch antenna but with the lengths of the inset-fed (y0) calculated by well known models available in the literature. The return loss value of the GA optimized antenna is presented below −40 dB at the resonant frequency.