Nguyen-Huy Hoang, Tran-Viet Duc-Nguyen, Kim-Thi Phuong, Tran-Huy Hung
Faculty of Electrical and Electronic Engineering, PHENIKAA University, Yen Nghia, Ha Dong, Hanoi 12116, Vietnam.
Faculty of Radio-Electronic Engineering, Le Quy Don Technical University, Hanoi 11917, Vietnam.
PLoS One. 2025 May 6;20(5):e0321091. doi: 10.1371/journal.pone.0321091. eCollection 2025.
This paper presents a circularly polarized (CP) microstrip patch antenna with high gain and compact size characteristics. For high gain radiation, the principle is to employ high-order mode patch. By using diagonal feed and unequal center crossed slot, two orthogonal modes including TM03 and TM30 modes are generated with equal magnitude and [Formula: see text] phase difference. Thus, the high-order mode patch antenna can radiate CP waves with high gain. To achieve small lateral dimensions with low back radiation, the patch is surrounded by a substrate integrated waveguide (SIW) cavity. For validation, measurement is implemented on an antenna prototype. The final design has overall dimensions of 1.27[Formula: see text] [Formula: see text] 1.27[Formula: see text] [Formula: see text] 0.03[Formula: see text] at the center operating frequency. The measured operating bandwidth, in which reflection coefficient and axial ratio are respectively less than -10 dB and 3 dB, is from 5.435 to 5.475 GHz. Within this band, the antenna exhibits high gain radiation of about 12 dBi. Besides, compared to the antenna without SIW cavity, the back radiation of the proposed design can be decreased by two times.
本文提出了一种具有高增益和紧凑尺寸特性的圆极化（CP）微带贴片天线。对于高增益辐射，其原理是采用高阶模贴片。通过使用对角馈电和不等中心交叉缝隙，产生了幅度相等且相位差为[公式：见原文]的包括TM03和TM30模式在内的两个正交模式。因此，高阶模贴片天线能够辐射高增益的圆极化波。为了在实现小横向尺寸的同时降低后向辐射，贴片被基片集成波导（SIW）腔体包围。为进行验证，对天线原型进行了测量。最终设计在中心工作频率下的整体尺寸为1.27[公式：见原文]×1.27[公式：见原文]×0.03[公式：见原文]。测得的工作带宽（其中反射系数和轴比分别小于-10 dB和3 dB）为5.435至5.475 GHz。在该频段内，天线呈现出约12 dBi的高增益辐射。此外，与没有SIW腔体的天线相比，所提设计的后向辐射可降低两倍。
