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

Abstract

To reduce the sidelobe level (SLL) and widen the bandwidth, this paper uses the differential evolution algorithm to optimize the array element spacing and excitation amplitude, and designs an 8element 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. INDEX TERMS Coupled feed, differential evolution algorithm, low sidelobe, microstrip antenna arrays, non-uniform spacing.

A 60 GHz Rhombic Patch Array Antenna With High Gain, Low Sidelobe Level, and Reduced Array Area

“…In [13], a W-band 1626 array antenna achieved low SLL through serial patches with tapered widths. In [14], an 8-element coupled patch array antenna with non-uniform spacing and groove length was reported. The design method is complicated.…”