Humberto X. Araujo

Metamaterial cell patterns applied to Quasi-Yagi antenna for RFID applications

In this work, a Quasi-Yagi antenna is designed to operate at 2.4 GHz for RFID applications. The proposed device is composed by a Quasi-Yagi antenna surrounded by fractal metamaterial structures placed at strategic positions, improving bandwidth and enhancing the antenna tunability at a desired frequency. Design guidelines for the combination of fractal structures and the Quasi-Yagi antennas are presented. The obtained results show that the use of the proposed antenna in RFID systems is very promising.

Analysis and characterization of different metamaterial patterns embedded on a Quasi Yagi antenna for RFID application

The analysis and characterization of different types of metamaterials patterns, such as fractal cells, Jerusalem-Cross-Pair, SRR — split ring resonator and CSRR — complementary split ring resonator, associated with an UHF Quasi-Yagi antenna are performed. The basic metamaterial cells pattern employed are composed by periodical arrangement of cooper strips located at strategic positions of the structure. Owing to its unit cell symmetry, isotropic response is provided to any linearly polarized incident wave. The target of this study is to define the best combination of metamaterial patterns for RFID applications.

Novel techniques to improve the GTEM chamber performance by applying metamaterial concepts on the excitation sector: The APEX characterization

In this work it is presented the analysis and characterization of different types of metamaterial patterns, such as fractal cells, Jerusalem-Cross-Pair, SRR — Split Ring Resonator and CSRR — Complementary Split Ring Resonator printed on the septum of a GTEM chamber. The main goal is to improve the chamber overall performance and to optimize it in terms of frequency for the electromagnetic compatibility analysis of integrated circuits and electronic boards. Experimental results are compared to simulated ones showing the advantages of the tuned characteristic of the patterned septum in comparison to the conventional type. This technique appears as an option for the performance optimizations of compact GTEM chambers.

CMOS Low Noise Amplifier Topology Using Compact Wu Folded Active Inductor

This work presents a topology proposal of a 0.35um CMOS cascode low noise amplifier using an active inductor. The inductance required to output of cascode pair is synthesized by an active inductor in Compact Wu Folded configuration. The LNA presents a gain of 12.04 dB with a noise figure of 4.78 dB at 1.8 GHz. The layout is presented occupying an active area of 0.165 mm2. The results are satisfactory, validating a compact design and demonstrating the technical feasibility of this topology in the band of interest.

Proposal of an RF CMOS Integrated Circuit Topology for Spatial Multiplexing of Local Elements (SMILE)

Spatial multiplexing of local elements (SMILE) is a front-end architecture which uses one radio frequency (RF) channel to carry multiplexed information from multiple ones. For this scheme, this paper proposes a fully multiplexing 0.35-μm RF CMOS integrated circuit (IC). The one uses an low noise amplifier (LNA) with four inputs to accomplish the multiplexing. To translate the frequency to the base-band, a double-balanced mixer and a voltage-controlled oscillator (VCO) are used. The presented results are satisfactory, validating the proposed compact design, and showing the viability of this topology for SMILE applications.