Abstract This paper presents the implementation of a 3-bit microstrip fractal-based phase shifter operating in the 430 MHz to 470 MHz frequency range. The fractal structure is used to confine different delay line lengths in the same area due to the space-filling properties of the used Hilbert fractal curve. The proposed design has three bits corresponding to 45, 90, and 180 degrees phase changes selected according to the switching circuit based on a Double Pole Double Throw (DPDT) switch implemented with PIN diodes. Comparisons between simulated and measured results are shown according to the chosen degree of use of PIN diodes.

Abstract This paper presents a compact and planar reconfigurable filtenna for application in Wireless systems. The filtenna is composed of a UWB circular antenna and a filter with two trapezoidal resonators. The filter is integrated on the antenna feed line and has a band-pass frequency response. The filtenna frequency response reconfiguration is achieved by changing the capacitance of a varactor diode, placed between filter resonators; the capacitance varies continuously from 1.32 pF to 4.09 pF according to an applied bias voltage. The varactor capacitance analog variation defines the filtenna frequency of operation, which can be varied from 2.2 GHz to 3.4 GHz with an average bandwidth of 200 MHz, while maintaining the radiation characteristics of the UWB antenna. Simulated and measured filtenna results are shown according to varactor diode bias, demonstrating multiband operation using a compact planar design.

Resumo Lymeon Förster, 1869 é um grande gênero de Cryptinae (Ichneumonidae) com distribuição predominantemente neotropical, onde fêmeas atacam pequenos casulos de vários grupos de insetos e ovissacos de aranha. No presente estudo, relatamos o primeiro registro da interação entre a vespa parasitoide Lymeon sp. (Ichneumonidae), com o ovissaco da aranha Araneus vincibilis (Araneidae) no Nordeste do Brasil. Observamos que, embora a fêmea de A. vincibilis cuide dos ovos que foram atacados por Lymeon sp, a larva da vespa consumiu cerca de 80% dos ovos da aranha, indicando que tanto o cuidado maternal quanto a barreira física oferecida pelo ovissaco não podem fornecer defesa absoluta contra predadores.

Abstract Lymeon Förster, 1869 is a very large genus of the Cryptinae (Ichneumonidae) with predominantly Neotropical distribution where females attack small cocoons of various groups of insects and spider eggs-sac. In the present study, we report the first record the interaction between the parasitoid wasp Lymeon sp. (Ichneumonidae), with eggs-sac of spider Araneus vincibilis (Araneidae) in Northeastern Brazil. We observed that although the female of A. vincibilis cares for the eggs that were attacked by Lymeon sp, the wasp larva consumed about 80% of spider eggs, indicating that both maternal care and the physical barrier offered by the eggs-sac may not provide absolute defense against predators.

Abstract This paper proposes a new Frequency Selective Surface (FSS) with modifications on the Jerusalem Cross (JC) geometry to provide a multiband response. Fractal levels are created by introducing concentric self-similar JC copies in the original unit cell. This modification results in new dipoles at the structure which allows for the appearance of new bands proportional to these diploles’ lengths, while maintaining total unit cell size. Three fractal levels of the JC FSS are studied in this paper, and third level presents five resonant frequencies which are f1 = 1.78 GHz, f2 = 6.42 GHz, f3 = 8.69 GHz, f4 = 10.94 GHz and f5 = 12.98 GHz. Simulation results for the insertion loss (S21), surface current distribution and measurement results are presented.

We have used a parameter - free potential, obtained from data analysis at sub-barrier energies, to explain our measurements of elastic and several inelastic scattering cross sections for the 16,18O + 58Ni systems at an energy above the barrier. The data were analyzed through extensive coupled-channel calculations. Transfer cross sections could also be explained by the same interaction, which is consistent with the more fundamental São Paulo potential.

We obtained theoretical fusion cross sections based on a new and accurate procedure to calculate the Coulomb and nuclear interactions between deformed nuclei. The calculations were performed within the context of the barrier penetration model with zero point motion for the 64Ni + 64Ni system.

Extensive systematizations of theoretical and experimental nuclear densities and of optical potential strengths extracted from heavy-ion elastic scattering data analyses at low and intermediate energies are presented. The energy-dependence of the nuclear potential is accounted for within a model based on the nonlocal nature of the interaction. The systematics indicates that the heavy-ion nuclear potential can be described in a simple global way through a double-folding shape, which basically depends only on the density of nucleons of the partners in the collision. The possibility of extracting information about the nucleon-nucleon interaction from the heavy-ion potential is investigated.