Conformal Microstrip Antenna Array Research Articles

A wideband cylindrical conformal microstrip mimo antenna array

AbstractIn this paper, a wideband cylindrical conformal microstrip antenna array employing a proximity‐coupled feeding mechanism with a cavity‐backed configuration is designed and fabricated. Compared with other conformal microstrip patch antennas by using linear subarrays assembled piecewise, this design uses Teflon instead of traditional dielectric layers, and makes it possible to process the whole conformal array without splicing, obtaining the freedom in unit size and array radius adjustment except ease of manufacturing and assemblage. Combined with the optimization of the cavity size, an array with 4 × 4 elements is obtained which has a bandwidth of 40% from 8 to 12 GHz and a gain of 16.4 dB.

Radiation pattern synthesis in conformal antenna arrays using modified convex optimization technique

In this paper, a modified convex optimization technique is used for radiation pattern correction in a cylindrical-shaped conformal microstrip array antenna. The technique uses numerical simulations to optimize the amplitude and phase excitations, with the goal to decrease the Euclidean distance between the desired field pattern and the obtained (simulated/measured) field pattern while maintaining the main beam direction, null's location, and side lobe levels under control. Two prototypes of 1 × 4 $$ 1\times 4 $$ and 2 × 4 $$ 2\times 4 $$ conformal microstrip antenna array deformed from linear/planar structure to the prescribed cylindrical shape, with different radii of curvature, are studied to demonstrate the performance of the proposed technique. The proposed convex optimization model when applied to conformal antenna array possesses fast computing speed and high convergence accuracy for radiation pattern synthesis, which can be a valuable tool for engineering applications.

A hybrid GA-PSO optimization algorithm for conformal antenna array pattern synthesis

This paper introduces a hybrid genetic algorithm and particle swarm optimization algorithm (GA-PSO) dedicated to pattern synthesis of conformal antenna arrays. Taking advantages of both methods, the proposed hybrid GA-PSO optimization algorithm has fast convergence speed and high convergence accuracy when applied to antenna array pattern synthesis. To show the performance of the hybrid optimization algorithm, several typical test functions and optimization examples of a linear array pattern synthesis are illustrated. Finally, a 4 × 2 cylindrical conformal microstrip antenna array as a practical synthesis example is studied to demonstrate the proposed algorithm. The simulated and measured results have shown the proposed method is effective and reliable for conformal antenna array pattern synthesis.

Design of a Full Solid Angle Scanning Cylindrical-and-Conical Phased Array Antennas

In this paper, a full solid angle scanning cylindrical-and-conical (CYLCON) conformal phased array antenna (PAA) is designed. First, a microstrip Yagi antenna with low profile and small size is proposed and discussed. Second, a cylindrical conformal Yagi antenna array consisting of 24 aforementioned 8-element Yagi antennas is designed and optimized. Simulation results show that the Yagi antenna array can realize low-elevation beam scanning in the region of $ 0 {^{\circ }} \le \theta \le 30 {^{\circ }}$ , $30 {^{\circ }} \le \varphi \le 150 {^{\circ }}$ with low sidelobe levels and sharp beams. Third, CYLCON conformal microstrip antenna arrays are developed to realize the broadside beam scanning. Afterwards, an integrated PAA by combining the aforementioned conformal arrays along with feeding networks is constructed to achieve full solid angle scanning. Finally, a prototype is fabricated, the measured results show that it can realize beam scanning in the regions of $ 0 {^{\circ }} \le \theta \le 30 {^{\circ }}$ , $30 {^{\circ }} \le \varphi \le 150 {^{\circ }}$ , and $30 {^{\circ }} \le \theta \le 180 {^{\circ }}$ , $60 {^{\circ }} \le \varphi \le 120 {^{\circ }}$ , which meet well with those of the simulated. By arranging proper number of arrays along the perimeter accompanied with the switchable feeding configurations, a full solid angle scanning can be achieved.

Full wave analysis of the arbitrarily arranged spherical conformal microstrip antenna array

The surface integral equation is adopted to analyse the characteristics of the arbitrarily arranged spherical conformal microstrip antenna array based on the moment method. The Rao–Wilton–Glisson basis function and triangle function are used to simulate equivalent current on the patch and probe, respectively. A novel basis function at the junction of wire and surface is proposed to ensure continuity of the current from probe to patch. Then, the magnetic frill loop is used as excitation source in this study, and the field on the antenna surface generated by magnetic frill loop is deduced with the help of magnetic dyadic Green's functions on the surface of sphere. For the antenna array analysis, the characteristic basis function method combined with equivalent dipole method is employed to save the consumed memory and computation time. The characteristics of several pairs of conformal spherical microstrip antennas are presented and shown to be in good agreement with data from literatures and FEKO software. At last, a result comparison between the method in this study and FEKO software is drawn to show the efficiency of this method.

Analysis on spherical conformal microstrip antenna array by characteristic basis function method

Spherical conformal microstrip antenna array which is used widely in the field of aeronautics is analyzed by the full wave analysis in this paper. Using the surface integral equation with spherical dyadic Green's function can decrease the number of unknowns remarkably, and also reduce the demand of memory as compared with the method using volume-surface integral equation. The curvilinear triangle is proposed to mesh the surface of the microstrip antenna array, which can simulate the characteristic of spherical surface accurately. Firstly, the problem about probe feed model is solved successfully by introducing the half Rao-Wilton-Glisson function and boundary charge, and the image method is used to treat the line integral singularity problem. Then, the characteristic basis function method is employed to further save memory and computation time further by reducing the rank of impedance matrix. Finally, the input impedance and far-field spherical conformal microstrip antenna array of different sizes are analyzed. Results are in good agreement with those in the literature and simulation software, and thus the validity and effectiveness of the analysis method are demonstrated.

Radiation Pattern Synthesis for Arrays of Conformal Antennas Mounted on an Irregular Curved Surface using Modified Genetic Algorithms

An E-shaped conformal microstrip antenna array mounted on an irregular curved surface which is similar to an aerocraft cavity in shape is developed in this paper. In view of the narrow bandwidth of the microstrip antenna, an E-shaped element is applied instead of the traditional rectangular element. Furthermore, an element structure of uneven thickness is adopted in order to take into account the effects of the carrier on the resonance frequency and bandwidth of the conformal array. Then, an 8-element conformal microstrip antenna array is designed and the radiation pattern is synthesized using the modified genetic algorithms (MGAs). Compared with the standard genetic algorithms (SGAs), MGAs has a much more fast convergence speed and need less computational time to reach the expected value. The result shows that the optimized azimuth radiation pattern is almost omnidirectional and the elevation radiation pattern is concentrated in the horizontal direction. It can be seen that the proposed method of MGAs is an effective means for designing the conformal antenna array on an irregular curved surface.

Accurate Analysis of Conformal Antenna Arrays with Finite and Curved Frequency Selective Surfaces

In this paper, a full-wave volume-surface integral equation approach is presented for the analysis of conformal microstrip antenna arrays with finite curved frequency selective surface (FSS) radomes. The volume integral equation is applied to the dielectric region of the composite structure, while the surface integral equation is used on the conductive surface. The integral equations are solved using the method of moments (MoM), with the precorrected-FFT (P-FFT) method used to reduce the memory requirement and accelerate the matrix-vector products in the iterative solution of the equation. With this method, FSSs and antennas of arbitrary shape and finite size can be modelled and the effects of the FSS on the characteristics of the antenna can be accurately investigated.