Two types of broad-band antennas are widely used for electromagnetic interference (EMI) measurements in the frequency range from 30 to 1000 MHz. Log-periodic dipole antennas (LPDA) are mainly used for the range above 300 MHz and biconical antennas for the range less than 300 MHz. These two antennas have linear polarization. However, EMI measurements can sometimes be more conveniently made with ...

A significant space reduction of a Planar Log-Periodic Dipole Array (LPDA) is achieved in this work. This reduction was performed by utilizing the first order iteration meander shape dipole in the design of a planar LPDA. The minimization procedure is illustrated in this work by presenting two designs for a Euclidean LPDA with linear dipoles and a meander LPDA operating over the entire S freque...

This paper presents a new approach for design of the log-periodic dipole array antenna (LPDA) based on using of different design parameters in the LPDA elements to control the antenna behavior. In the proposed procedure, the design parameters can control the value of forward gain over the operating frequency range, and also adjust the gain flatness. Furthermore, this design procedure can decrea...

–Technological advances and developments in solar activities, particularly in solar radio bursts, have created a demand of constructing log periodic dipole antenna (LPDA) to monitor this phenomenon in radio region. In this paper, we make an effort in designing a portable LPDA that suitable with the criteria, specification and practical enough although is the boom length size of the antenna is 3...

On single sample condition, current face recognition algorithm yields serious performance drop or even fail to work, therefore a face recognition algorithm based on LGBP and locality preserving discriminant analysis (LPDA) was proposed. Image enhancement and geometric transformation were firstly introduced to single sample face image for face reconstruction, making reconstruct image and origina...

The intracellular pathogen Legionella pneumophila translocates a large number of effector proteins into host cells via the Icm/Dot type-IVB secretion system. Some of these effectors were shown to cause lethal effect on yeast growth. Here we characterized one such effector (LecE) and identified yeast suppressors that reduced its lethal effect. The LecE lethal effect was found to be suppressed by...

Abstract—A printed Log-periodic dipole array (LPDA) is presented, operating over the C, X and Ku bands. The antenna feeding structure consists of two coaxial cables, in order to realize an infinite balun which provides the required broadband input matching. The second coaxial cable mirrors the first one, connected to the antenna input, and is capable of both stabilizing the antenna phase center...

A novel approach to broadband log-periodic antenna design is presented, where some of the most powerful evolutionary algorithms (EAs) are applied and compared for the optimal design of wire log-periodic dipole arrays (LPDA) using NEC (Numerical Electromagnetics Code). The target is to achieve an optimal antenna design with respect to maximum gain, gain flatness, Front to Rear ratio (F/R) and SW...

In bacteria, cysteines of cytoplasmic proteins, including the essential enzyme ribonucleotide reductase (RNR), are maintained in the reduced state by the thioredoxin and glutathione/glutaredoxin pathways. An Escherichia coli mutant lacking both glutathione reductase and thioredoxin reductase cannot grow because RNR is disulfide bonded and nonfunctional. Here we report that suppressor mutations ...