Design, Analysis, and Optimization of the Array of Axial Rectangular Slots on a Cylindrical Waveguide

Mahmoud Sharafi Masouleh,Malek Adjouadi,Amin Kargar Behbahani

doi:10.1109/access.2021.3092997

Mahmoud Sharafi Masouleh, Malek Adjouadi + Show 1 more

Open Access

https://doi.org/10.1109/access.2021.3092997

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Abstract

In the current work, for the first time, the design equations for an array of rectangular slots axially placed on a cylindrical waveguide are driven and presented, making it possible to attain asymmetrical and non-broadside patterns with higher bandwidths. The method of least squares is then used for both the radiation pattern synthesis with the specified side lobe level and the array input impedance matching. For optimization, the error function comprised of the three terms of impedance matching, array pattern synthesis, and slot design equations is constructed. To minimize the error function, the genetic algorithm combined with the conjugate gradient method is utilized and the geometrical characteristic of the slots defined. This procedure increases the design speed and provides the means to synthesize any desired pattern for an array of axial rectangular slots on a cylindrical waveguide. Numerical and fabrication examples are presented as illustrations of the proposed synthesis method. The results of the proposed method are verified by using the commercial software High-Frequency Structure Simulator (HFSS) in comparison to measurement results obtained out of the proposed prototype of a fabricated antenna operating at the frequency of 9 GHz.

Highlights

In the literature, extensive analysis of different antenna topologies with different shapes and designs is reported
Deployment, manufacturing techniques, and production procedures have all been widely investigated at microwave frequencies for the different application domains, ranging from medical wearable applications to radars [5]–[8]
Through this work and for the first time, an analytical method is proposed for both purposes, i.e., the design equations and the synthesis of an array composed of rectangular slots arranged along the central axis of a cylindrical waveguide

Summary

INTRODUCTION

Extensive analysis of different antenna topologies with different shapes and designs is reported. Through this work and for the first time, an analytical method is proposed for both purposes, i.e., the design equations and the synthesis of an array composed of rectangular slots arranged along the central axis of a cylindrical waveguide. The developed error function comprises three terms: impedance matching, array pattern synthesis, and slot design equations. SYNTHESIS OF AN AXIAL SLOT ARRAY ON THE CYLINDRICAL WAVEGUIDE WITH A MODIFIED TAYLOR PATTERN AT 9 GHz To determine the error function, both the space between adjacent slots and the length of the slots are assumed identical. These assumptions will result in the simplicity of the calculation process to minimize computational time. It should be noticed that because ripples amplitude is proportional to the number of slots distributed around the circumference of the waveguide, increasing the number of slots just for the sake of having an omnidirectional pattern increases the level of ripple in the omnidirectional radiation pattern (azimuthal plane)

CONCLUSION

FIRST AND SECOND DESIGN EQUATION DERIVATION

EXTRACTING THE FIRST DESIGN EQUATION FOR AN

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