倒F型天線
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倒F型天線(英語:inverted-F antenna)是用於無線通訊的一種天線,主要運作於特高頻和微波頻率。構造包含導電的接地平面以及一個與之平行的單極天線。相對於簡易版的單極天線,此設計有兩個好處:第一,這種天線的長度較短且體積更加小巧,可被安裝在行動裝置中。第二,這種天線無需其他元件即可透過設計與饋電電路達成阻抗匹配,提高效率。
![](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Planar_Inverted_F-Shaped_DECT_Antenna.jpg/150px-Planar_Inverted_F-Shaped_DECT_Antenna.jpg)
與倒F型天線有關的構想最早出現在1950年代,當時構想的是一個立體的彎折天線。然而,如今倒F型天線最為廣泛的應用形式是平面倒F型天線(英語:planar inverted-F antenna,PIFA)。其接地平面和天線平行於一平面上,大幅節省了立體空間,小巧的尺寸使其能夠融入於行動通訊裝置中。PIFA能被以微帶線形式印刷在電路板上。
PIFA是一種貼片天線。許多的貼片天線(包含PIFA)都可實現寬頻和多頻功能,實現方式包含使用耦合諧振器(coupled resonator)或是在天線上打洞。
發展與歷史
倒F型天線是由廣受使用的四分之一波長(quarter-wave)單極天線演變而來,其構造包含一個接地平面以及一個直立於平面上的桿狀天線,天線由底部接受饋電。最早具有F狀造型的天線於1940年代被發明,[1]這個天線從位於中間位置的分支接受饋電,而其底部則連接到接地平面。從饋電線一直到接地平面這個區段的天線具有短截线的作用。只要調整這個區段的長度,就能夠改變天線的輸入阻抗,因此設計者可以透過改變饋電點位置來達成阻抗匹配。
註腳
- ^ Waterhouse & Novak, p. 19
參考書目
- Ali, M.; Guangli Yang; Huan-Sheng Hwang; Sittironnarit, T., "Design and analysis of an R-shaped dual-band planar inverted-F antenna for vehicular applications", IEEE Transactions on Vehicular Technology, vol. 53, iss. 1, pp. 29–37, January 2004.
- Barton, "Nosecone Inverted-F (IFA) for S-Band Telemetry"[失效連結], DTIC, 2017
- Cohen, N., Fractal antenna applications in wireless telecommunications", Professional Program Proceedings: Electronics Forum of New England, 1997, pp. 43–49, 6–8 May 1997, IEEE ISBN 0780339878.
- Hall, Peter S.; Lee, E.; Song, C. T. P., "Planar inverted-F antennas", pp. 197–227, in Waterhouse, Rod (ed), Printed Antennas for Wireless Communications, John Wiley & Sons, 2008 ISBN 0470512253.
- Hall, Peter S.; Yang Hao, Antennas and Propagation for Body-Centric Wireless Communications, 2nd ed., Artech House, 2012 ISBN 1608073769.
- Kervel, Fredrik, 868 MHz, 915 MHz and 955 MHz inverted F Antenna (页面存档备份,存于互联网档案馆), Texas Instruments, Design Note DN023 30 September 2011.
- Kin-Lu Wong, Yen-Yu Chen, Saou-Wen Su, Yen-Liang Kuo, "Diversity dual-band planar inverted-F antenna for WLAN operation" (页面存档备份,存于互联网档案馆), Microwave and Optical Technology Letters, vol. 38, iss. 3, pp. 223–225, 5 August 2003.
- King, Ronold W. P.; Harrison, C. W., Jr.; Denton, D. H., Jr., "Transmission-line missile antennas", Sandia Corp Technical Memo 436-58, vol. 14, November 1958.
- King, Ronold W. P.; Harrison, C. W., Jr.; Denton, D. H., Jr., "Transmission-line missile antennas", IRE Transactions on Antennas and Propagation, vol. 8, iss. 1, pp. 88–90, January 1960.
- Liu, Z. D.; Hall, P. S.; Wake, D., "Dual frequency planar inverted F antenna", IEEE Transactions on Antennas and Propagation, vol. 45, iss. 10, pp. 1451–1458, October 1997.
- Petosa, Aldo, Frequency-Agile Antennas for Wireless Communications, Artech House, 2013 ISBN 1608077691.
- Prasad, Shiela; King, Ronold W. P., "Experimental study of inverted L-, T-, and related transmission-line antennas" (页面存档备份,存于互联网档案馆), Journal of Research of the National Bureau of Standards, vol. 65, no. 5, pp. 449–454, September–October 1961.
- Sánchez-Hernández, David A., Multiband Integrated Antennas for 4G Terminals, Artech House, 2008 ISBN 1596933984.
- Waterhouse, Rod; Novak, Dalma, "Wireless systems and printed antennas", pp. 1–36, in Waterhouse, Rod (ed), Printed Antennas for Wireless Communications, John Wiley & Sons, 2008 ISBN 0470512253.
- Yarman, Binboga Siddik, Design of Ultra Wideband Antenna Matching Networks, Springer, 2008 ISBN 1402084188.