Intermodulation in active reconfigurable antennas

Due to the application of active components into antennas these became a source of distortion on wireless communication systems. In this paper we explore the nonlinear effects occurring in a frequency reconfigurable antenna operating with a PIN Diode. We describe the measurement setup used to check the antenna intermodulation products and the measured compression and third order intermodulation limitations of a frequency reconfigurable antenna, operating at the UMTS and WLAN frequencies.

On the choice of posittioning and cluster size for fixed relay stations in a LTE network

The long term evolution (LTE) is one of the latest standards in the mobile communications market. To achieve its performance, LTE networks use several techniques, such as multi-carrier technique, multiple-input-multiple-output and cooperative communications. Inside cooperative communications, this paper focuses on the fixed relaying technique, presenting a way for determining the best position to deploy the relay station (RS), from a set of empirical good solutions, and also to quantify the associated performance gain using different cluster size configurations. The best RS position was obtained through realistic simulations, which set it as the middle of the cell's circumference arc. Additionally, it also confirmed that network's performance is improved when the number of RSs is increased. It was possible to conclude that, for each deployed RS, the percentage of area served by an RS increases about 10 %. Furthermore, the mean data rate in the cell has been increased by approximately 60 % through the use of RSs. Finally, a given scenario with a larger number of RSs, can experience the same performance as an equivalent scenario without RSs, but with higher reuse distance. This conduces to a compromise solution between RS installation and cluster size, in order to maximize capacity, as well as performance.

RFID passive tag antenna for cork bottle stopper

In this paper we propose a possible design for a RFID tag antenna embedded into cork. The antenna is small and conformal and intended to be used into bottle stoppers for tracking and logging purposes of wine or other beverages. The proposed design is based on an inductive ring and an added resistance in order to modify the current distributions of the antenna. The resulting antenna has a relatively directive radiation pattern and despite the small efficiency it is able to operate with a commercial RFID reader at a reasonable distance. © 2014 IEEE.

UHF RFID tag antenna for bottle labeling

In this paper we present a possible design for a passive RFID tag antenna on paper substrate to be integrated into bottle labels. Considering the application scenario, we verified and determined the permittivity and dissipation factor of the materials in order to simulate all the possible sources that would influence the antenna performance. The measured results reported a maximum reading range of 1.45 m even though the efficiency obtained with the antenna integrated into the bottle was only of 3%. © 2014 IEEE.

A Design methodology for integrated inductor-based DC-DC converters

A design methodology for monolithic integration of inductor based DC-DC converters is proposed in this paper. A power loss model of the power stage, including the drive circuits, is defined in order to optimize efficiency. Based on this model and taking as reference a 0.35 mu m CMOS process, a buck converter was designed and fabricated. For a given set of operating conditions the defined power loss model allows to optimize the design parameters for the power stage, including the gate-driver tapering factor and the width of the power MOSFETs. Experimental results obtained from a buck converter at 100 MHz switching frequency are presented to validate the proposed methodology.

Compact, frequency reconfigurable, printed monopole antenna

This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results.

Halting the fuse discharge propagation using optical fiber microwires

We report and analyze the halting of the fuse effect propagation in optical fiber microwires. The increase of the mode field diameter in the tapered region decreases the optical intensity resulting in the extinction of the fuse effect. This fiber element presents a low insertion loss and can be introduced in the optical network in order to protect the active equipment from the damage caused by the fuse effect.

Halting the fuse discharge propagation Using optical fiber microwires

We report and analyze the halting of the fuse effect propagation in optical fiber microwires. The increase of the mode field diameter in the tapered region decreases the optical intensity resulting in the extinction of the fuse effect. This fiber element presents a low insertion loss and can be introduced in the optical network in order to protect the active equipment from the damage caused by the fuse effect. (C) 2012 Optical Society of America