本論文提出一新穎的可調之多操作頻帶天線設計概念，運用匹配網路設計理論來實現多頻獨立連續可調天線。藉著可調式匹配網路—附屬於一簡單型態尚未優化架構的Semi-UWB天線饋入端，整體可視為單一元件操控對應一單獨獨立頻帶的多個窄頻帶可調天線，且具有可調範圍極廣、有高選擇性的特性。其原理是採用阻抗匹配的觀念去詮釋，藉控制後端電路使得天線有可調機制。由於天線的輸入阻抗為頻率相關的連續分佈函數；對超寬頻天線不同頻率的輸入阻抗去做匹配，因而天線有了選擇性的操作頻帶的出現，且擁有超寬頻的可調頻率範圍；進一步同時對多個頻率進行匹配，即有多個操作頻帶的出現。相較於傳統實現可調天線的電磁原理設計，非直接於天線輻射體本身的設計，而改成藉後端匹配電路調整饋入來實現天線可調機制；並不限特定種類天線架構，只需天線擁有寬頻特性即可。同時針對匹配網路做深入的分析研究，建立相關理論以利設計。藉此可了解不同架構上元件值所對應之匹配效能差異，以及當元件有製程差異時所造匹配誤差和效能變化，最後針對不同之阻抗區域分佈值所適合之匹配架構挑選來說明。
在可調單一操作頻率天線上，藉所設計的T型C-L-C架構匹配網路，只需調控單一電容值，即可控制匹配網路工作頻率，使得天線操作頻率有偏移的效果，適用任意寬頻天線。在本文中將詳細說明架構選擇原因與提升匹配天線的整體Q值、抑制雜訊方法。驗證上，單頻可調天線原型用兩組不同電容、電感值實現，藉號角天線(horn antenna)對此可調天線的收發效能進行效能實測。此單頻天線可調操作頻帶分別為1.8~2.8 GHz以及2.1~3.6 GHz，可調頻率比達156%與170%，平均頻寬約300 MHz (8~15%)，轉換功率增益至少為-0.94 dB，可達-0.58 dB。
在可調雙頻帶天線上，新穎的雙頻帶獨立可調天線設的計概念被提出。對雙頻率操作頻帶天線上，搭配吾人所設計之“十字型匹配網路”，只需分別調控匹配網路中兩端不同的電容值，即可使天線的雙頻f_L與f_H獨立可調操作頻率偏移的效果。任何的寬頻天線搭配此雙頻可調式匹配網路後，即可成為全新雙頻可調天線，且擁有極大的操作範圍。且說明架構的設計、雙頻匹配數值理論與提升雙頻天線的選擇性的數值方法。同樣的，分別施予不同的偏壓於兩變容二極體可獨立控制高/低頻帶，量測雙頻天線可調操作S11頻帶範圍；再與另一個號角天線無線對傳量測S21效能。此雙頻天線可調操作頻帶分別為f_L 1.39~2.34 GHz以及f_H 2.1~3.6 GHz，可調頻率比達168%與132%，平均頻寬f_L約50 MHz、f_H為148 MHz左右的兩操作窄頻，最高轉換功率增益為-2.1 dB。利用新提出之“十字型匹配網路”即可較一般傳統複雜的設計，更簡易的實現可調頻率範圍寬廣之雙頻可調式天線。
由量測結果上可知匹配網路實現可調天線的概念有著良好的效能與優點，由其所提供的電路設計增加的自由度與所推導確立的理論，也已經進一步成功模擬驗證出三頻段或多頻段可調天線。其為一般限制天線種類的可調設計無法輕易達成的。本論文的創新與貢獻點，在於跳脫傳統的設計概念，僅使用單一支寬頻天線，搭配可調式匹配網路，即可實現單頻、多頻帶頻率獨立連續可調天線，並建立相關參數與推導，使本理論更加完整可廣泛應用。

This thesis proposes a novel design of a tunble multi-band antenna, which uses the matching network design theory to realize a continually and independently tunable multi-band antenna. Through the tunable matching network –a wideband antenna feed side attached to a simple un-optimized geometrical framework – the entity can be viewed as a separate independent antenna with wide tuning range which can be operated through a singular component, and highly selective multiple narrow-band tunable antennas. Its principle can be interpreted from an impedance matching perspective; the antenna becomes tunable by means of controlling the back-end matching network circuit. The matching on the input impedance at various frequencies enables the selective operational frequencies of the ultra-broad band antenna, and possesses an ultra-broad band of tunable frequency range. Further matching of multiple frequencies results in multiple operational frequency bands. Contrary to the traditional implementation of electromagnetic-based tunable antennas, which design the antenna radiator itself, the revised design achieves the mechanism of a tunable antenna through back-end matching circuitry. It puts no restrictions on the particular type of antennas, and the only characteristic it requires isthe broad bandwidth of the antennas. In-depth analysis and study on the matching network were carried out to construct the relevant theory to facilitate the design. Further discussions also reveal the performance vaiation of the matching component values from the process variations and the deviation of matching and changes of performance on different frameworks. At the end, the selection of the appropriate framework was explained in view of the different impedance distribution.
On tunable singular operational frequency antennas, the matching network can be controlled by regulating a single capacitance on the designed T-type (C-L-C) framework of a matching network, and thereby offset the operational frequencies of the antenna. This can apply to any broadband antenna. This thesis gives a detailed account on why this particular framework is chosen, and on the methods to enhance the overall Q value of the matching antenna and suppress un-wanted frequencies noise other than the operational bands. When verifying, a single-frequency tunable antenna prototype was built with two sets of different capacitors and inductances, and tests were performed on the transceiving performance of the tunable antenna using a horn antenna. The tunable operational bands of this single-frequency antenna are 1.8~2.8 GHz and 2.1~3.6 GHz, respectively, and the tunable frequency ratios are 156 % and 170 %; the average bandwidth is approximately 300 MHz (8~15 %), and the transducer power gain is at least -0.9 dB(optimal -0.58 dB).
As to the tunable dual-band antennas, the concept of novel, dual-band independently tunable antennas can be extended from the previous proposed structure. On dual-band operational antennas matched with the cross-shaped matching network that we proposed, the independently tunable operational frequency can be offset on the f_L and f_Hof the dual-band antenna by means of varying the capacitances at both arms of the matching network, respectively. Any broadband antenna, when coupled with the dual-band tunable matching network, will become a brand-new tunable dual-band antenna, featuring a super wide operational range. We explained the design of the framework, the dual-band numerical matching theory, and the methods to enhance the selectivity of the dual-band antenna. Likewise, the tunable operational range of the S11 frequency band of the dual-band antenna is measured while different bias voltages are applied to the two varactor diodes indepentantly; then wireless S21 was measured between the two horn antennas at a distance of 60 cm. The tunable operational range of this dual-band antenna is f_L 1.39~2.34 GHz and f_H 2.1~3.6 GHz, respectively; the operational frequency rates are 168% and 132%, and the two narrow-bands for operation has an average bandwidth f_L of approximately 50 MHz, and f_H 148 MHz, and the transducer power gain is at least -2.1 dB (maximal -1.09 dB). Compared with the conventional complex designs, the cross-shaped matching network can easily realize a dual-band antenna with wide-range adjustability.
The measured results indicate that the concept of implementing tunable antennas through a matching network has good performance and advantages, and the extra degree of freedom and the deducted theory have successfully simulated and verified the tunable triple-band or multiple-band antennas which would have been very difficult to accomplish in conventional design. The contribution of this thesis including breaking off from conventional design concepts and using only a single broad-band antenna coupled with a tunable matching network to devise single-band and multi-band independently tunable antennas, with the relevant construction of parameters and deduction which enables the theory to be applied more comprehensively and extensively.

[1] J. Mitola, III and G. Q. Maguire, Jr., "Cognitive radio: making software radios more personal," Personal Communications, IEEE, vol. 6, pp. 13-18, 1999.
[2] http://www.fer.hr/_download/repository/Debogovic_kvalifikacijski.pdf
[3] P. Vainikainen, et al., "More than 20 antenna elements in future mobile phones,
threat or opportunity?," in Antennas and Propagation, 2009. EuCAP 2009. 3rd
European Conference on, 2009, pp. 2940-2943.
[4] C. Zhang, et al., "Reconfigurable Antenna for Simultaneous Multi-Service Wireless
Applications," in Radio and Wireless Symposium, 2007 IEEE, 2007, pp. 543-546.
[5] D. Peroulis, et al., "Design of reconfigurable slot antennas," Antennas and
Propagation, IEEE Transactions on, vol. 53, pp. 645-654, 2005.
[6] A. C. K. Mak, et al., "Reconfigurable Multiband Antenna Designs for Wireless
Communication Devices," Antennas and Propagation, IEEE Transactions on, vol.
55, pp. 1919-1928, 2007.
[7] D. E. Anagnostou, G. Zheng, M. T. Chryssomallis, J. C. Lyke, G. E.Ponchak, J.
Papapolymerou, C. G. Christodoulou, Design, "Fabrication, and Measurements of an RF-MEMS-Based Self Similar Reconfigurable Antenna", IEEE Trans. Antennas
Propag., Vol. 54, No. 2, pp. 422-432, February 2006
[8] T. Debogović, A. Karabelj, J. Bartolić, " Dual Band Reconfigurable Slot Antenna
with High Frequency Ratio ", Proc. of the 2008 MRRS Symposium, September
22-24,2008
[9] N.C. Karmakar, "Shorting Strap Tunable Stacked Patch PIFA ", IEEE Trans. Propa
, Vol. 52, No. 11, pp. 2877-2884, November 2004
[10] J.T. Aberle, S.-H. Oh, D. T. Auckland, S. D. Rogers, " Reconfigurable Antennas for
Portable Wireless Devices ", IEEE Antennas and Propagation Magazine, Vol. 45,
No. 6, pp. 148-154, December 2006
[11] D. Kornek, J. Meyer, C. Orlob, I. Rolfes, "Reconfigurable Triangular Patch Antenna for Pattern Diversity, "Proc. of The Third European Conference of Antennas and Propagation (EuCAP), pp. 3744-3747, March 23-27, 2009
[13] L. Petit, L. Dussopt, J.-M. Laheurte, "MEMS-Switched Parasitic Antenna Array for
Radiation Pattern Diversity, " IEEE Trans. Antennas Propag., Vol. 54, No. 9, pp.
2624-2631, September 2006
[14] R. Sorrentino, R. V. Gatti, L. Marcaccioli, B. Mencagli,"Electronic Steerable MEMS Antennas, " Proc. of The First European Conference of Antennas and Propagation (EuCAP), November 6-10, 2006
[15] R. Jeen-Sheen and W. Jia-Feng, "Aperture-Coupled Microstrip Antennas With Switchable Polarization," Antennas and Propagation, IEEE Transactions on, vol. 54, pp. 2686-2691, 2006.
[16] T. Debogović, S. Škokić, J. Bartolić, "Electronically Switchable Multi-Polarization Circular Patch Antenna for Conformal Arrays, " Proc. Of The First European Conference of Antennas and Propagation (EuCAP),November 6-10, 2006
[17] F. Yang, Y. Rahmat-Samii, " Patch Antennas with Switchable Slots (PASS) in Wireless Communication: Concepts, Designs and Applications, " IEEE Antennas and Propagation Magazine, Vol. 47, No.2, pp. 13-29, April 2005
[18] N. Jin, F. Yang, Y. Rahmat-Samii, "A Novel Patch Antenna with Switchable Slot (PASS): Dual-Frequency Operation with Reversed Circular Polarizations, " IEEE Trans. Antennas Propag., Vol. 54, No. 3, pp 1031-1034, March 2006
[19] T. Debogović, J. Bartolić, " Capacitively Fed Annular Ring Microstrip Antenna with Reconfigurable Circular Polarisation, " Proc. of The Fourth European Conference of Antennas and Propagation (EuCAP),April 12-16, 2010
[20] H.A.Watson, "Microwave Semiconductor Devices and Their Circuit Applications, " McGraw-Hill, New York, USA, 1969
[21] H. F. AbuTarboush, et al., "Widely tunable multiband reconfigurable patch antenna for wireless applications," in Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on, 2010, pp. 1-3.
[22] M. G. S. Hossain and T. Yamagajo, "Reconfigurable printed antenna for a wideband tuning," in Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on, 2010, pp. 1-4.
[23] F. Ghanem, et al., "Switched UWB to narrowband planar monopole antenna," in Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on, 2010, pp. 1-3.
[24] E. Ebrahimi, et al., "A reconfigurable narrowband antenna integrated with wideband monopole for cognitive radio applications," in Antennas and Propagation Society International Symposium, 2009. APSURSI '09. IEEE, 2009, pp. 1-4.
[25] S. L. S. Yang, et al., "Frequency Reconfigurable U-Slot Microstrip Patch Antenna," Antennas and Wireless Propagation Letters, IEEE, vol. 7, pp. 127-129, 2008.
[26] L. Hui, et al., "A Simple Compact Reconfigurable Slot Antenna With a Very Wide Tuning Range," Antennas and Propagation, IEEE Transactions on, vol. 58, pp. 3725-3728, 2010.
[27] A. F. Sheta and S. F. Mahmoud, "A Widely Tunable Compact Patch Antenna," Antennas and Wireless Propagation Letters, IEEE, vol. 7, pp. 40-42, 2008.
[28] C. Re-Yu, et al., "Switchable printed monopole antenna with frequency diversity for WiFi/2.6 GHz WiMAX/3.5 GHz WiMAX applications," in TENCON 2007 - 2007 IEEE Region 10 Conference, 2007, pp. 1-3.
[29] C. Pei-Ling, et al., "Compact and Tunable Slot-Loop Antenna," Antennas and Propagation, IEEE Transactions on, vol. 59, pp. 1394-1397, 2011.
[30] M. Abdallah, et al., "Frequency tunable monopole coupled loop antenna with broadside radiation pattern," Electronics Letters, vol. 45, pp. 1149-1151, 2009.
[31] A. Sankarasubramaniam, et al., "Design guidelines for tunable coplanar and microstrip patch antennas," in Microwave Conference, 2007. European, 2007, pp. 1302-1305.
[32] O. Se-keun, et al., "A novel PIFA type varactor tunable antenna with U-shaped slot," in Antennas, Propagation & EM Theory, 2006. ISAPE '06. 7th International Symposium on, 2006, pp. 1-3.
[33] L. Shuangxi, et al., "Design of a frequency-tunable dual-band planar monopole antenna for handheld terminals," in Wireless And Optical Communications Networks (WOCN), 2010 Seventh International Conference On, 2010, pp. 1-3.
[34] W. Junfeng, et al., "Switching a Dual Band PIFA to Operate in Four Bands," in Antennas and Propagation Society International Symposium 2006, IEEE, 2006, pp. 2675-2678.
[35] N. Behdad and K. Sarabandi, "Dual-band reconfigurable antenna with a very wide tunability range," Antennas and Propagation, IEEE Transactions on, vol. 54, pp. 409-416, 2006.
[36] N. Viet-Anh, et al., "A Compact Tunable Internal Antenna for Personal Communication Handsets," Antennas and Wireless Propagation Letters, IEEE, vol. 7, pp. 569-572, 2008.
[37] Y. J. Sung, "Simple tunable dual-band microstrip patch antenna," Electronics Letters, vol. 45, pp. 666-667, 2009.
[38] S. V. Shynu, et al., "Meandered slot arm loaded electronically tunable microstrip antenna using varactors," in Antennas and Propagation Society International Symposium 2006, IEEE, 2006, pp. 221-224.
[39] N. Viet-Anh and P. Seong-Ook, "Compact Tunable-PIFA Antenna for Multiband Slim Handsets," in Antenna Technology: Small Antennas and Novel Metamaterials, 2008. iWAT 2008. International Workshop on, 2008, pp. 362-365.
[40] Z. Yuliang, et al., "A compact antenna with two independently tunable frequency bands," in Antennas and Propagation Society International Symposium, 2008. AP-S 2008. IEEE, 2008, pp. 1-4.
[41] C. T. P. Song, et al., "Wide tunable dual-band reconfigurable antenna for future wireless devices," in Antennas & Propagation Conference, 2009. LAPC 2009. Loughborough, 2009, pp. 601-604.
[42] Y. Chin-Lung, "Novel high selective band-tunable antennas over ultra-wide ranges using reconfigurable matching network," in Antennas and Propagation Society
International Symposium, 2009. APSURSI '09. IEEE, 2009, pp. 1-4.
[43] D. M. Pozar, Microwave Engineering, Addison-Wesley, 1990
[44] G. Fischer, W. Eckl, and G. Kaminski, “RF-MEMS and SiC/GaN as enabling
for a reconfigurable multi-band/multi-standard radio,” Bell Labs Tech. J., vol. 7, pp. 169–189, 2003.
[45] R. N. Simons and R. Q. Lee, “Impedance matching of tapered slot antenna using a
dielectric transformer,” Electron. Lett., vol. 34, pp. 2287–2289, Nov. 1998.
[46] J. de Mingo, A. Valdovinos, A. Crespo, D. Navarro, and P. Garcia, “An RF
electronically controlled impedance tuning network design and its application to an
antenna input impedance automatic matching system,” IEEE Trans. Microw.
Theory Tech., vol. 52, no. 2, pp.489–497, Feb. 2004.
[47] W. C. E. Neo, Y. Lin, X. D. Liu, L. C. N. de Vreede, L. E. Larson, M. Spirito, M. J.
Pelk, K. Buisman, A. Akhnoukh, A. de Graauw, and L. K. Nanver, “Adaptive
multi-band multi-mode power amplifier using integrated varactor-based tunable
matching networks,” IEEE J. Solid-State Circuits, vol. 41, no. 9, pp. 2166–2176,
Sep. 2006.
[48] A. Tombak, "A Ferroelectric-Capacitor-Based Tunable Matching Network for
Quad-Band Cellular Power Amplifiers," Microwave Theory and Techniques, IEEE
Transactions on, vol. 55, pp. 370-375, 2007.
[49] H. T. Zhang, H. Gao, and G. P. Li, “Broad-band power amplifier with a novel
tunable output matching network,” IEEE Trans. Microw. Theory Tech., vol. 53, no.
11, pp. 3606–3614, Nov. 2005.
[50] T. Vaha-Heikkila, M. Lahdes, M. Kantanen, and J. Tuovinen, “Onwafer Noise
parameter measurements at W-band,” IEEE Trans. Microw.Theory Tech.,vol.51,no.
6, pp. 1621–1628, Jun. 2003.
[51] C. E. McIntosh, R. D. Pollard, and R. E. Miles, “Novel MMIC sourceimpedance
tuners for on-wafer microwave noise-parameter measurements,” IEEE Trans.
Microw. Theory Tech., vol. 47, no. 2, pp. 125–131, Feb. 1999.
[52] J. H. Sinsky and C. R. Westgate, “Design of an electronically tunable microwave
impedance transformer,” in IEEE MTT-S Int. Microw. Symp. Dig., Denver, CO,
1997, vol. 2, pp. 647–650.
[53] T. Vaha-Heikkila, J. Varis, J. Tuovinen, and G. M. Rebeiz, “W-band RF MEMS
double and triple-stub impedance tuners,” in IEEE MTT-S Int. Microw. Symp. Dig.,
2005, vol. 1–4, pp. 923–926.
[54] A. Jrad, A. L. Perrier, R. Bourtoutian, J. M. Duchamp, and R. Ferrari,“Design of an ultra compact electronically tunable microwave impedance transformer,” Electron. Lett., vol. 41, pp. 707–709, Jun.2005.
[55] J. Papapolymerou, K. L. Lange, C. L. Goldsmith, A. Malczewski, and J. Kleber,
“Reconfigurable double-stub tuners using MEMS switches for intelligent RF
front-ends,” IEEE Trans. Microw. Theory Tech., vol. 51, no. 1, pp. 271–278, Jan.
2003.
[56] R. B. Whatley, Z. Zhou, and K. L. Melde, “Reconfigurable RF impedance tuner for
match control in broadband wireless devices,” IEEE Trans. Antennas Propag., vol.
54, no. 2, pp. 470–478, Feb. 2006.
[57] R. N. de Lima, B. Huyart, E. Bergeault, and L. Jallet, “MMIC impedance matching
system,” Electron. Lett., vol. 36, pp. 1393–1394, Aug. 2000.
[58] P. Scheele, et al., "Continuously tunable impedance matching network using
ferroelectric varactors," in Microwave Symposium Digest, 2005 IEEE MTT-S
International, 2005, p. 4 pp.
[59] L.-Y. V. Chen, R. Forse, D. Chase, and R. A. York, “Analog tunable matching network using integrated thin-film BST capacitors,” in IEEE MTT-S Int. Microw. Symp. Dig., 2004, vol. 1, pp. 261–264.
[60] M. Schmidt, E. Lourandakis, A. Leidl, S. Seitz, and R. Weigel, “A comparison of
tunable ferroelectricπand T-matching networks,” in 37th Eur. Microw. Conf.,
Munich, Germany, 2007, pp. 98–101.
[61] Y. Sun and J. K. Fidler, "Component value ranges of tunable impedance matching
networks in RF communications systems," in HF Radio Systems and Techniques,
Seventh International Conference on (Conf. Publ. No. 441), 1997, pp. 185-189.
[62] G. D. Vendelin, A. M. Pavio, U. L. Rohde, “Microwave Circuit Design Using
linear and nonlinear Techniques,” Wiley-Interscience, 1990.
[63] I. C. Hunter, et al., "Microwave filters-applications and technology," Microwave
Theory and Techniques, IEEE Transactions on, vol. 50, pp. 794-805, 2002.
[64] C. Hoarau, et al., "Complete Design and Measurement Methodology for a Tunable
RF Impedance-Matching Network," Microwave Theory and Techniques, IEEE
Transactions on, vol. 56, pp. 2620-2627, 2008.
[65] E. Alekseev, et al., "77 GHz high-isolation coplanar transmit-receive switch using
InGaAs/InP PIN diodes," in Gallium Arsenide Integrated Circuit (GaAs IC)
Symposium, 1998. Technical Digest 1998., 20th Annual, 1998, pp. 177-180.
[66] B. E. Carey-Smith and P. A. Warr, "Distortion Mechanisms in Varactor Diode-Tuned Microwave Filters," Microwave Theory and Techniques, IEEE Transactions on, vol. 54, pp. 3492-3500, 2006.
[67] Soubhi Abou Chahine, Maria Addam, Hadi Abdel Rahim, Areej Itani, Hiba Jomaa , “A Modified Circular Disc Monopole Ultra Wide Band Antenna,” IEEE Advances in Computational Tools for Engineering Application, ACTEA '09 ,pp.71 – 75,July 2009.
[68] G. H. Stauffer, “Finding the lumped element varactor diode model,”High Frequenc
Electronics, Summit Technical Media, 2003.
[69] http://www.aeroflex.com/AMS/Metelics/pdfiles/MGV_Series_Hyperabrupt
[70] 林高洲,“寬頻衛星通訊系統之運用與展望”中華民國電子認證委員會
[71] J. H. Winters, "Smart antennas for wireless systems," Personal Communications, IEEE, vol. 5, pp. 23-27, 1998.