An optimal design of a linear antenna array is presented. The antenna array is optimized using a particle swarm optimization based method in order to produce a radiation pattern that has the minimum possible side lobe level and the maximum possible gain at the desired direction. The method has been applied to collinear wire-dipole arrays and seems to be suitable for improving the radiation patt...

Slope efficiency (SE) is an important performance metric for lasers. In conventional semiconductor lasers, SE can be optimized by careful designs of the facet (or the modulation for DFB lasers) dimension and surface. However, photonic wire lasers intrinsically suffer low SE due to their deep sub-wavelength emitting facets. Inspired by microwave engineering techniques, we show a novel method to ...

An antenna model is proposed for long (L >> A) lasers with subwavelength cross sections (wire lasers). It is shown that the far-field pattern of the wire lasers is determined by the ratio of the wavelength to the length. The radiation of the wire laser is predicted to be concentrated in a narrow beam theta approximately radical(2lambda/L) for laser modes where the longitudinal phase velocity is...

The log-periodic dipole array (LPDA) has become the most popular commercial antenna for reception of TV signal in VHF and UHF bands in Europe. The antenna consists of two booms of a square cross section to which dipoles are attached (Figure 1). The booms play the role of the feeding two-conductor line. The dimensions of the boom are relatively large compared to the wavelength and the dipole len...

Wireless applications, particularly with multiple resonances, put new demands on antennas pertaining to size, gain, efficiency, bandwidth, and more. One promising approach in this regard is to use fractal geometries to find the best distribution of currents within a volume to meet a particular design goal. In the miniaturization of wire antennas it has been found that the electromagnetic coupli...

The Active Loop Antenna Model ALA100HG is a large aperture antenna designed to provide improved performance compared to traditional active and passive antennas. The ALA100HG has two modes of operation; at Medium and Low Frequencies the antenna is a high efficiency broadband Loop; for High frequencies the antenna has a response similar to a Longwire. The ALA100HG is primarily designed to reduce ...

Antennas which are fed by a “shunt” or other method in which a part of the antenna comprises a portion of an electrically small one-turn loop, so that the feed is in essence a sort of autotransformer, are quite common, particularly at frequencies above 10 megahertz. Shunt feed arrangements for grounded vertical tower radiators, such as those used for medium wave broadcasting, are less common. A...

We have modeled and simulate asymmetric microstrip folded dipole antenna on substrate materials and study the antenna performances. The conventional wire dipole antenna configurations are converted into corresponding microstrip version. The complementary nature of parallel coplanar strip line and waveguide models have been used to model the dipole antenna. The transmission line parameters namel...