Marcelo Bender Perotoni

A Palm Tree Antipodal Vivaldi Antenna With Exponential Slot Edge for Improved Radiation Pattern

This letter presents an Exponential Slot Edge Antipodal Vivaldi Antenna (ESE-AVA), with improved radiative features as compared to the conventional Antipodal Vivaldi Antenna (AVA) design. It extends the low-end bandwidth limitation, mitigates the side and back lobe levels, corrects squint effect, and increases its main lobe gain. In order to confirm those features, a comparative study among the ESE-AVA, the low directivity conventional AVA and two popular modifications, regular slot edge (RSE) and the tapered slot edge (TSE) AVA is performed. A comparison between AVA and the proposed ESE-AVA at 6 GHz shows an improved gain of 8.3 dB, -15.5 dB of Side Lobe Level (SLL), and 0 degrees of main lobe squint (MLS), in contrast with 5 dB of gain, - 5 dB of SLL, and 5 degrees of MLS in the conventional AVA. By comparing the ESE-AVA with RSE-AVA and TSE-AVA, it was observed that its notches in exponential shape, similar to open the main radiator, besides mitigating the SLL also directs the E-fields distributions towards the main lobe. It reflects into a main lobe gain improvement.

Power integrity simulation of power delivery network system

As a result of the increasing operating frequency and the number of transistors of IC, not only the signal integrity (SI), but the power integrity (PI) has also grown from non-existent to an important system. The objective of power integrity is to produce a clean signal for the high-speed driver by supplying a good source. A good source needs to fulfill two criteria: 1) meet the DC power requirement and 2) reduce the power fluctuation caused by the AC current switch. This paper will discuss power integrity simulation using the 3D fullwave simulation tool CST STUDIO SUITE®. The accuracy of the simulation results are also compared with the measurement results.

Wideband Planar Monopole Antennas for the Brazilian Digital TV System

This paper presents the design, construction and measurements (both at device and system level) of two different planar monopole antennas for the use in the receiving site of a Brazilian Digital TV System, operating in Ultra-High Frequency Range. The design goals were towards low cost, robustness and small volume antennas, for indoor applications and with good performance in terms of return loss within the frequency band. The antennas were designed and optimized using a full wave electromagnetic solver and had their performance compared to an ordinary wire monopole. The scattering parameters were simulated and measured as well as their performance when connected to a digital TV tuner and to a spectrum analyzer, in a dense urban indoor environment was evaluated, as well.

Planar monopole antennas for the Brazilian Digital TV

This article analyzes three different monopole antennas for the use in the Brazilian Digital TV System (range from 479 to 773 MHz). Two low cost, planar monopole antennas were designed using a full wave electromagnetic solver and compared with an ordinary wire monopole. The scattering parameters were simulated and measured, as well as their behaviors when connected to digital TV tuners and to a spectrum analyzer, in an urban indoor environment.

Cyber-Attacks Based in Electromagnetic Effects

This article covers eavesdropping on computer and auxiliary data communication equipment by means of hardware, namely unintended electromagnetic emanations. The physical basis that underlies the process is covered, alongside with a canonical electromagnetic simulation. Some known cases of these exploits are covered, and real world examples of a leaking coaxial cable and a shielding conductive sheet are measured in the laboratory, with results relate to the data protection and its implications. The measured shielding effectiveness of the sheet proved to comply with usual Tempest requirements.

Microwave absorber materials characterization: bulk absorbing and electrical/magnetic parameters

Microwave absorber materials are used extensively in anechoic chambers for antenna measurement, to emulate free-space conditions. They are also used to suppress unintended radiations in consumer electronic products (so that they present conformity to existing regulations) and other applications. Their characterization usually shows the amount of damping in a certain frequency range, and it depends on the materials used in the mixture and its overall geometry. This article deals with Brazilian and international manufactured, low cost absorbing materials, characterized in both bulk format (damping) as well as its material parameters (electrical permittivity and magnetic permeability).

Increasing the interest in antennas and microwave courses

Subjects related to electromagnetics in undergraduate electrical engineering courses are normally seen as problematic by students, due to the inherent complexity and abstract concepts. The effect is that students are drawn away from related research areas. Some approaches were developed to enhance the motivation and physical insight of the concepts seen in class. Electromagnetic compatibility is used as a source of real world examples where students see that applied electromagnetics is not a field unrelated with their experiences. In addition to that, final projects with handmade antennas help guide students through a complete design cycle, from analytical formulation to the actual measurement, so that the connections concerning the theory, simulation, prototyping, and measurements are closed. These techniques were applied and provided good results, increasing the understanding and motivation among students toward radio-frequency and antenna-related areas.

Coilgun Velocity Optimization With Current Switch Circuit

An inductive coil gun is a solenoid surrounding a cylindrical metallic armature (the projectile), both electromagnetically coupled. One or more capacitors discharge a stored voltage quickly through the coil, configuring a kind of RLC circuit, with the pulse-shaped current generating a magnetic field inside the coil that accelerates the projectile. Once the projectile crosses an equilibrium point inside the coil, the existing magnetic field pulls the armature back, therefore reducing the final muzzle velocity and decreasing the efficiency—defined as the ratio between the available capacitor electrostatic versus the slug kinetic energies. This paper describes a system that monitors the armature position inside the coil, with a laser beam, and automatically cuts the current when the projectile reaches the equilibrium point. The system, named current switch circuit, enables higher velocities using the same set of coilgun and projectiles, providing a higher efficiency.

Desenvolvimento e análise de um Protótipo Coilgun

The article describes the construction and simplified analysis of a small-scale Coilgun prototype – electromagnetic weapon that launches a metallic slug whose operation is similar to linear electric motors, also seen in magnetic locks. The design can be constructed with low cost and easily available components, though it involves sophisticated electromagnetism concepts. The system can be employed to Laboratory experiments on Physics as well as on Engineering, to address Electromagnetic Conversion of Energy, namely linear electric motors and actuators. The article discusses circuit models, the electromagnetic force on the slug and also field plots generated from a commercial simulator. The used instrumentation for velocity measurement is also presented, alongside with measured data.

UWB (Ultra wide band) accordion shaped planar monopole antenna

This paper presents the complete synthesis, 3D numerical analysis, construction and measurement of an Ultra wideband (UWB) planar monopole antenna. The antenna measurements showed good agreement with the predicted numerical results, for both scattering parameters and gain patterns.