A low-profile wideband Conical Beam antenna which uses two concentric annular ring slots in substrate integrated waveguide (SIW) technology is presented. First, a single ring antenna is considered and then the effect of introducing the second slot on bandwidth is investigated and high bandwidth is achieved. A brief parametric study for different slot width is presented. A prototype of the proposed antenna is fabricated and measured. The measured reflection coefficient is in good agreement with simulation. The theoretical result is also provided for S11 to validate the simulation and measurement results. The proposed antenna shows 30% bandwidth in 17 GHz center frequency (|S11<-10 dB). Radiation pattern was measured in three different frequencies in the entire frequency bandwidth. Maximum measured radiation efficiency is 93%. The antenna is very simple and low profile with a planar structure. Electrical dimensions are (1. 76𝜆 𝜆 0×1. 76𝜆 𝜆 0×0. 08𝜆 𝜆 0) with very simple feeding network which could be a suitable choice in many practical applications from anti-collision radars to WLAN applications.

One of the methods for optimizing the radiation characteristics of microstrip antennas is using metamaterial as substrate and superstrate. In this research, a rectangular microstrip antenna with circular polarization and Conical pattern is designed at 2.2 GHz frequency. For creating circular polarization cutting corner method is used and to create Conical pattern, 4 array rectangular microstrip patch antennas are used and each antenna is feeded by microstrip line and whole of structure is feeded by a 50 Ω SMA connector. To improve the radiation characteristics and optimize the dimensions of antenna, a 10×10 aray layer of metamaterial is used as substrate and Then the antenna has been made. The metamaterial parameters such as Permeability (µ) and Permittivity (ε) is extracted by Nicolson-Rose method. The simulation results show that the antenna dimensions is decreased 30% and bandwidth and gain of the antenna are increased 17% and 45% respectively. All the simulation process for antenna designation is implemented in HFSS 18.2 software.

In this paper, an exact closed-form solution is presented for free vibration analysis of Euler-Bernoulli Conical and tapered Beams carrying any desired number of attached masses. The concentrated masses are modeled by Dirac’s delta functions which creates no need for implementation of compatibility conditions. The proposed technique explicitly provides frequency equation and corresponding mode as functions with only two integration constants which leads to solution of a two by two eigenvalue problem for any number of attached masses. Using Basic functions which are made of the appropriate linear composition of Bessel functions leads to make implementation of boundary conditions much easier. The proposed technique is employed to study effect of quantity, position and translational inertia of the concentrated masses on the natural frequencies and corresponding modes of Conical and tapered Beams for all standard boundary conditions. Unlike many of previous exact approaches, presented solution has no limitation in number of concentrated masses. In other words, by increase in number of attached masses, there is no considerable increase in computational effort.

Lattice structures, due to their low weight and high performance as structural elements, have been widely used in different aerospace applications. In this paper, effective parameters on the design of anisogrid lattice Conical shells are investigated. First, filament winding patterns regarding the desired axial strength is decided. Then, regarding geometrical relations, effective parameters in order to form the anisogrid cell are identified. Distance of circular ribs from each other has an important role in determining the Conical lattice structure and eventually in deriving the stiffness matrix. Finally, considering the relations, finite element analysis model of the lattice Conical structure has been performed by ABAQUS software and buckling analysis under axial loading is done. In deriving the strength results, the verifications of references of this paper and the classic theory have been used.

this article presents the coupled thermoelasticity of a truncated functionally graded Conical shell under thermal shock load. The classical coupled thermoelasticity theory is employed to set the partial differential equations of motion of the Conical shell. The shell governing equations are based on the fi, rst-order shear deformation shell theory that accounts for the transverse shear strains and rotations. The solution is obtained by transforming the governing equations into the Laplace domain and using the Galerkin fi, nite element method in the Laplace domain to calculate the displacement components. The physical displacement components in real time domain are obtained by the numerical inversion of the Laplace transform. Temperature distribution is assumed to be linear across the shell thickness. Radial displacement, axial stress, axial force, and temperature versus time are calculated and the effect of relaxation time and power law index are examined. Comparison indicates that an increase in the radial vibration amplitude and a decrease of vibration frequency occur when changing the material from ceramic to metal. The results are validated with the known data in the literature.

Background and Aim: Microneedle technology has led to huge changes in the field of drug delivery medicine. Using microneedles, the drug can be injected locally, painlessly, and in very low and controlled doses with high precision. Local drug delivery through the skin with microneedles has many advantages over other methods of drug delivery. In this method, the drug does not enter the gastrointestinal tract and blood circulation, and therefore non-target organs are protected from the side effects of the drug. The present study is designed to construct an array of micron needles using the lithography method. Methods: In this study, a silicon microneedle array is fabricated using the photolithography method with proper adjusting of the effective parameters. The constructed microneedle array has 256 needles with a height of 500 microns, a base diameter of 250 microns, and a center-tocenter distance of 600 microns. Results: Microscopic images show that the microneedles are tapered with a relatively sharp tip. Their surface is smooth and without cracks, and they also have an acceptable resemblance to the original design. Conclusion: The produced microneedle array can be used directly to pierce the skin and increase its permeability by creating micron holes. In addition, this array can be used as a mold for the production of microneedles with malleable materials in the casting method.

A finite element analysis is presented for sloshing and impulsive motion of liquid-filled Conical tanks during lateral anti-symmetric excitation. The performed analyses led to the development of a number of charts which can be used to identify the natural frequency, the mode shapes of Conical tanks for both fundamental and the cos (q) -modes of vibration. Conical tank geometry was described with several parameters namely, bottom radius (Rb) total height of liquid (h), angle of inclination of the tanks (qi), as variables. Numerical result of the free vibration was obtained for the cases of Conical tanks with qi=0 and compared with existing experiments and other predicated results, showing a good agreement between the experiment and numerical results.

In this paper, free vibration of the joined sandwich Conical-Conical shell is investigated by using differential quadrature method (DQM). It is assumed that the Conical shell is truncated. The core of sandwich Conical-Conical shell is made from the four different types of materials such as Polyether ether ketone (PEEK), Polycarbonate (PC), Solid polypropylene (SPP) and high density polyimide foam (HDPF), and Aluminum is supposed for material of inner and outer skin layers. The first-order shear deformation shell theory (FSDT) is adopted to formulate the theoretical model and governing equations of motion are derivated by Hamilton’ s principle. The governing equations of motion, the boundary conditions of the two ends of the shell and the continuity conditions at the interface section of shell segments, are discretized by means of the DQM. Then, eigenvalue problem, and, consequently natural frequencies are achieved. The effects of thickness, length of the shell, cone angle, material of the core and boundary conditions on natural frequencies are investigated. To verify the accuracy of this method, comparisons of the present results with results available in the open literature and Abaqus software are performed.