序列式旋轉饋入之極化可調附株正方平板天線陣列

Polarization-Agile Stub-Loaded Square Patch Antenna Array with Sequential Rotation Feed

陳心如(Hsinju Chen)

指導教授 ： 陳士元

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202001446

摘要

本論文提出一序列式旋轉饋入之四單元極化可調附株正方平板天線陣列。其天線單元為一正方形平板天線，兩鄰邊以兩 PIN 二極體分別連接兩附株，藉由切換直流電壓改變左、右手圓極化。該設計亦可應用在不同頻率，包含衛星導航系統頻帶 1.575 GHz 以及第五代行動通訊的 28 GHz。
在陣列方面，由於單饋入之圓極化平板天線傳統上頻寬受限制，為增加利用範圍，採取序列式旋轉饋入。此饋入方式會因為左、右手圓極化，使得每單元天線饋入點需要不同的路程差。在此設計三株加載線相移器，藉由兩相移器與天線上兩株之 PIN 二極體，改變陣列上的單一直流電源切，即同時達成左、右手圓極化的切換。此外，我們也在天線輸入端設計耦合線濾波器作為直流斷電器。
在驗證方面，從固定式非可調天線著手，實作確認每一設計單元均合理運作，最後將極化可調的陣列製作在兩種板材上，各自均有強度相當的兩圓極化。以 Rogers RO4003C 板材為例，在其中心頻率使用 PIN 二極體切換極化，左手與右手圓極化可分別達 7.456 dBic 與 7.367 dBic。

關鍵字

平板天線 ； 序列式旋轉饋入 ； 極化可調天線 ； 圓極化 ； 加載線相移器

並列摘要

In this thesis, we proposed a novel design of a four-element polarization-agile stub-loaded square patch antenna array with sequential rotation feed circuitry. The simple structure of the proposed antenna element consists of a square patch symmetrically loaded with two PIN-diode connected short-circuited stubs. By applying positive and negative dc voltage, the polarization of the antenna can be switched between right- and left-hand circular polarizations. The antenna also operates as a linearly polarized patch when dc voltage is absent. This design is also applicable at different frequencies, including 1.575 GHz for GNSS applications and 28 GHz for 5G communications.

Since single feed circularly polarized patch antennas have narrow bandwidth, we implemented sequential rotation feed to increase it. This feeding method requires different phase delays for different sense of handedness. By designing triple-stub loaded-line phase shifters, we can switch the polarization of the array with a single dc source, which controls both the phase shifters and antenna stubs. Also, we designed a coupled-line filter at the array feeding for dc blockage.

We also conducted experiments for step-by-step verification on non-switchable antenna arrays, and ultimately designed polarization-agile arrays on two different substrates. Using Rogers RO4003C boards for the switchable design, we can achieve 7.367 dBic and 7.456 dBic at its center frequency for right- and left-handed circular polarizations respectively.

並列關鍵字

patch antennas ； sequential rotation ； polarization agility ； circular polarization ； loaded-line phase shifters

參考文獻

[1] D. P. Simpson, Cassell’s Latin Dictionary, 5th ed. New York, NY: Houghton Mifflin Harcourt Publishing Company, 1977.

[2] C. J. Caesar, Caesar’s Gallic War, 1st ed., trans. by W. A. McDevitte and W. S. Bohn. New York: Harper Brothers, 1869.

[3] “Antenna, n.,” inOEDOnline,OxfordUniversityPress, Mar. 2020. [Online]. Available: https://www.oed.com/view/Entry/8277.

[4] K. F. Lee, “A personal overview of the development of microstrip patch antennas,” in 2016 IEEE International Symposium on Antennas and Propagation (APSURSI), 2016, pp. 689–690.

[5] J. D. Kraus and R. J. Marhefka, Antennas for All Applications, 3rd ed. Singapore: McGraw-Hill, 2002.