A series-fed millimeter-wave (mm-wave) microstrip linear array with single-layer structure and wide operating bandwidth is proposed and investigated. The antenna array simply consists of a microstrip line and a series of short stubs that are periodically introduced on one edge of the microstrip line, at an interval of about one guide wavelength. Owing to the perturbation of the additional stubs, the original symmetrical E-field distributions on the two opposite edges of the microstrip line become asymmetrical, and the intensities of the equivalent magnetic currents are unequal and unable to cancel each other out as in a pure microstrip line. As a result, the stub-loaded microstrip line can radiate effectively, producing broadside radiation patterns. The introduction of stubs can also generate an extra resonant mode, which combines with the resonant mode of the microstrip line, yielding a wide bandwidth of over 20%. In addition, the microstrip array is simply fed by a coaxial probe, without involving any complex feeding network. Therefore, the array configuration is very simple and compact. For demonstration, a $1 \times 4\,\,1$ -D microstrip linear array operating at 27 GHz is fabricated and tested. The measured results show that the array has an impedance bandwidth of 21.40%, an average realized gain of 12.18 dBi, and a first sidelobe level (FSLL) of about −13 dB. Moreover, the FSLL can be decreased to −28.4 dB by tapering the width of the microstrip line. Finally, the design is extended to realize a $4 \times 4\,\,2$ -D microstrip planar array. This planar array can achieve an impedance bandwidth of 19.15% and an enhanced gain of 18.30 dBi.

中文翻译：

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串联馈电、单层和宽带毫米波微带阵列的设计

提出并研究了一种具有单层结构和宽工作带宽的串联馈送毫米波（mm-wave）微带线阵。天线阵列简单地由一条微带线和一系列短截线组成，这些短截线以大约一个引导波长的间隔周期性地引入微带线的一个边缘。由于附加短截线的扰动，微带线两个相对边缘上原来对称的电场分布变得不对称，等效磁流强度不等，不能像纯微带线一样相互抵消线。结果，加载短线的微带线可以有效地辐射，产生宽边辐射模式。短截线的引入还可以产生额外的谐振模式，它与微带线的谐振模式相结合，产生超过 20% 的宽带宽。此外，微带阵列仅由同轴探头馈电，不涉及任何复杂的馈电网络。因此，阵列配置非常简单紧凑。为了演示，制造并测试了一个 $1 \times 4\,\,1$ -D 微带线阵列，工作频率为 27 GHz。测量结果表明，该阵列的阻抗带宽为 21.40%，平均实现增益为 12.18 dBi，第一旁瓣电平 (FSLL) 约为 -13 dB。此外，通过缩小微带线的宽度，FSLL 可以降低到 -28.4 dB。最后，设计扩展以实现$4 \times 4\,\,2$ -D 微带平面阵列。这种平面阵列可以实现 19.15% 的阻抗带宽和 18.30 dBi 的增强增益。