Low Sidelobe Coupled Broadband Microstrip Array Antenna With Non-Uniform Spacing and Variable Groove Length

Fenggan Zhang,Tongmin Xu,Minli Yao

doi:10.1109/access.2020.3029610

Fenggan Zhang, Tongmin Xu + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.3029610

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Abstract

To reduce the sidelobe level (SLL) and widen the bandwidth, this article uses the differential evolution algorithm to optimize the array element spacing and excitation amplitude, and designs an 8-element coupled microstrip array antenna with non-uniform spacing and variable groove length. Based on the power equally divided feed network, the non-uniform length of the groove to achieve a quantitative change in the excitation amplitude. This method does not need to adjust the width of the microstrip line of the feed network one by one, nor is it limited to an array of equal spacing, which simplifies the complex design process. And to establish a mathematical relationship of all feeder segments to ensure that all array elements are in phase excitation under unequal spacing conditions. At the same time, the H-groove coupling feed form reduces the antenna Q value and increases the bandwidth. The measurement results show a gain of 16 dBi and an SLL of -19.5 dB within the operating bandwidth. And the antenna has a voltage standing wave ratio of less than 1.5 in the range of 13.84 to 15.62 GHz, which meets the bandwidth requirement of SatCom on-the-move.

Highlights

Modern communication pursues stability and large capacity, and puts forward higher requirements on the antenna sidelobe level and bandwidth
One type is the analytical method, including Chebyshev synthesis method [1], Taylor synthesis method [2]. This type of method is suitable for equidistant array antennas
This kind of algorithm takes the factors that affect the antenna sidelobe level as optimization variables, and it does not depend on the prior information, nor is it limited to the equal spacing array, and increases the freedom of design

Summary

INTRODUCTION

Modern communication pursues stability and large capacity, and puts forward higher requirements on the antenna sidelobe level and bandwidth. By changing the feeder width of the feeder network to weight the excitation amplitude of the array elements, the purpose of reducing the sidelobe level is achieved [3], [4]. With the improvement of computer performance, it has become a trend to use modern intelligent algorithms to reduce the antenna sidelobe level, including genetic algorithm [5] and differential evolution. Algorithm (DEA) [6], etc This kind of algorithm takes the factors that affect the antenna sidelobe level as optimization variables, and it does not depend on the prior information, nor is it limited to the equal spacing array, and increases the freedom of design. The change of the slit length can be used to control the excitation amplitude of the array element, thereby reducing the sidelobe level.

ANTENNA ELEMENT DESIGN

CONCLUSION