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 decrease the LPDA dimensions in comparison to the conventional design. Based on the proposed design method, several LPDA antennas are designed and simulated numerically by the method of moment. The simulation results show that this LPDA design procedure can be a good candidate for design of optimized antenna in different frequency bands.

This paper proposes a fundamental approach for radiation pattern correction of the mutually coupled circular dipole antenna array (CDAA) using parametric assimilation technique. The effect of mutual coupling is an indispensable part of any practical design issue of the antenna array. Many analytical and numerical techniques have been put forward in the past few decades for the calculation, compensation and reduction of mutual coupling effect. This paper shows an accurate method for mutual coupling correction by using a recently proposed technique called parametric assimilation technique, where the values of mutual impedance are calculated and assimilated with the values of the desired radiation pattern. The proposed technique is cost-effective, less complicated and easy to implement while achieves better performance for mutually coupled circular dipole antenna array synthesis. Grey Wolf Optimization (GWO) algorithm is a state-of-the-art stochastic algorithm applied here to find the optimal values of the current excitation weights and the inter-element spacing between each element of the CDAA for the desired, uncorrected and corrected far-field radiation pattern synthesis. PSO and DE optimization-based statistical results are also reported to compare the results obtained by using GWO algorithm to confirm the outstanding performance of GWO algorithm based design.

Dipole asymmetry is among the most important anomalies in the cosmic microwave background (CMB). A dipole, if primordial, would challenge the isotropy of the Universe. In this work, we propose a novel method to find the direction of the dipole and its amplitude and assess its significance. The method is based on the comparison of annular variances on the sphere. We find the direction on the sphere around which the difference of the annular variances on the two hemispheres is maximized. By applying this algorithm on symmetric CMB simulations we get the distribution of the measured dipole amplitude for these null cases, providing us with the baseline for quantifying the significance of dipole amplitude of any other CMB maps. In particular, we find the statistical significance of the observed Planck dipole to be 1. 6σ . Our simulations show that although the proposed method is not more powerful in detecting the dipole compared to other algorithms, its relatively low computational cost (performed in the pixel-space) is its advantage. This paves the way for a straightforward upgrade of the method which uses spherical caps instead of rings and thus, by increasing the number of pixels used in calculating the variance, improves the results significantly.

In this paper, a novel ultra-wideband dipole antenna with a simple structure and low cost is presented. The impedance bandwidth (S11≤ 10 dB) of the proposed antenna is (1. 2_4. 55GHz) 116%. The whole of S-band frequency (2_4GHz) is covered completely and a part of L, C frequency bands are enveloped. The minimum and maximum gains in operation bandwidth are 2. 48dBi and 7. 48dBi respectively. The 50-ohm coaxial cable is utilized for feeding the antenna. To eliminate the backflow of the antenna and impedance matching with the coaxial transmission line, a Bazooka balun is adopted. Analysis of the current distribution and electric and magnetic fields on the dipole element have been conducted. A prototype of the antenna is fabricated and return loss, gain and radiation pattern are simulated and measured. The simulation and measurement parameters are suitable agreement.

Classical trajectory (Monte Carlo) calculation ir used to calculate collision rare constants of ion-quadrupolar molecule interactions for the H-+C2H2 system The methods presented here takes into account the effect Of the induced dipole-induced dipole potential our ion-quadrupolar molecule collision rate constants. It is also assumed that the colliding particles have a definite size. The thermal energy collision rate constants are calculated at 300-3000 K temperature range and the kinetic energy dependence of rate constants Is examined at a relative, kinetic energy of the colliding particles in the range from tt thermal energy up to similar to 1.3 eV. It is suggested that the induced dipole-induced dipole potential term and the particles Size are important factors and should not be ignored when calculating collision rate constants of ion-quadrupolar molecule system.

To determine the probability of sewage infiltration into foundations of unborn structures, the Werner and the dipole - dipole arrays were used in an electrical resistivity tomograph operation in Masjed Soleiman City which is located in south west of Iran. Using Robust Constraint and Combined Marquardt and Occam algorithms, the measured apparent data were inverted to true electrical resistivity values separately then joint inversion was carried out using the data gathered by both arrays. Three drilled boreholes along the electrical resistivity profile were very useful in accurate interpreting the results. The Combined Marquardt and Occam algorithm provided better results than the Robust Constraint for presenting a subsurface electrical resistivity mode. Also, the electrical resistivity model resulting from the joint inversion of the Werner and dipole - dipole array data is more consistent with reality than the individual inversion of the data for each array.Keywords: Wenner, Dipole-dipole, electrode array, Joint inversion, electrical resistivity.

Sharifabad copper deposit is located on the Cenozoic volcanic belt in the northwest of Bardeskan, Khorasan Razavi Province. The host rocks of the mineralization are pyroxene andesite, tuff, agglomerate, limestone, sandstone, and micro conglomerate of the volcanic rocks of Eocene and Oligocene age. Alteration includes propylitic, silica and carbonate materials. Mineralization is restricted to the veins and veinlets and is controlled by the local faults. Mineralization mainly consists of chalcosite, magnetite, hematite, pyrite and malachite that occur in the cavities and fractures of the host rocks. Geophysical surveys using resistivity (Res) and induced polarization (IP) methods have been carried out along 5 survey lines. The results indicate high resistivity and IP values in the depth levels of 0-25 and 32-49 meters, and thus, relevant highly resistant horizons are identified. On the basis of the geological and geophysical studies in the area, eight locations for drilling exploration boreholes are proposed that probably contain highly concentrated copper mineralization. Introduction The Sharifabad copper deposit is situated in the Sabzevar zone and Eastern Iran Cenozoic volcanic rocks. The area is covered by a detailed exploration program, which includes preparation of the geological map of the area at 1: 5, 000 scale, and drilling several hundred meters of trenches. This study focuses on the copper bearing veins system and determination of subsurface mineralization by conducting geological and geophysical operations. For carrying out geophysical operations, 5 survey lines have been designed, and then, surveyed in the area. In this paper, the results of modeling and interpretation of geophysical data acquired along two survey lines DD1 and DD2 have been presented. The geophysical data include IP-Res measurements at 460 points along these two survey lines using dipole-dipole array with the electrode intervals of 20 meters that have been conducted by Omid Geological Engineering and Geo-Science Company. Methodology and Approaches The raw field geophysical data along the two survey lines DD1 and DD2 have been modeled using two-dimensional (2D) smooth Inversion by RES2DINV and ZONDRES2D software packages. The 2D model sections are displayed in threedimensional (3D) form using RockWorks software. The inverse modeling results and geological studies lead to the recognition of the copper mineralization zones and local faults in Sharifabad area. Results and Conclusions The results of geophysics studies in Sharifabad area show high resistivity and IP values in two depth levels 0 to 25 m and 32-49 m. On the basis of the geological and geophysical studies, eight locations for drilling exploration boreholes are proposed, and as a result, three boreholes have been drilled up to a depth ranging 33-40 m. Drilling studies confirm copper mineralization with high copper values in the depth of about 39m. These studies have also led to the identification of four local faults near the mineralization zones.