陳士元臺灣大學:電信工程學研究所曾俊維Tseng, Chun-WeiChun-WeiTseng2010-07-012018-07-052010-07-012018-07-052009U0001-0108200921485400http://ntur.lib.ntu.edu.tw//handle/246246/188315本論文首先提出一種以電容性負載進行縮小化的槽孔天線。這個方法是利用電容取代傳統的開路或短路的邊界條件，以縮短槽孔天線在相同共振頻率下所需的長度。由於吾人以微帶線偏移饋入槽孔天線，不僅能達到較佳的阻抗匹配，更無需額外的匹配電路。本論文亦提供一增加該微型化槽孔天線頻寬之方法，對於槽孔長度約為1/17真空波長的微型化槽孔天線，可達到3.2%的頻寬，淨空區之長寬分別為1/16真空波長及 1/19真空波長。最後，吾人利用變容二極體取代一般電容，以達到調整微型化槽孔天線之共振頻率之目的。經模擬與實驗證實，該天線共振頻率之可調範圍涵蓋1.18-2.42 GHz之頻寬。A novel miniaturized slot antenna terminated by a lumped capacitor is presented in this thesis. A lumped capacitor is placed at the truncated open end of a quarter-wavelength slot antenna to lower the resonant frequency; in other words, to reduce the slot length for the same resonance. The proposed slot antenna is offset fed by a microstrip line with an open stub, which is used mainly to tune out the input reactance of the antenna. With the conventional feeding structure, there is no need for any extra matching circuit. In this thesis, design guidelines for bandwidth enhancement of the miniaturized slot antenna are also discussed. A prototype antenna of slot length λ0 /17 etched on a small rectangular metallic area of dimensions λ0 /16  λ0 /19 provides an impedance bandwidth of 3.2%. Lastly, a varactor diode is used instead of the chip capacitor to attain the frequency tenability for the miniaturized slot antenna. The resultant design exhibits a very wide frequency tuning range between 1.18-2.42 GHz.Contents試委員審定書……………………………………………………………i謝……………………………………………………………………..…iii文摘要…………………………………………………...………………vbstract….………………………………………………...……………...viiontents……………………………………………………………………ixist of Figures……………………………………………………………xiist of Tables……………………………………………………………...xvhapter 1. Introduction………………………..…………………1.1 Motivation and literature survey..................………………………1.2 Chapter outline…………………………………………………4hapter 2. Review of Microstrip-Line-Fed Slot Antenna…………..……………….…….……………6.1 Modes and characteristics of offset-fed slot………………………6.2 Microstrip-to-slotline cross-junction transition…………………7hapter 3. Miniaturized Slot Antenna Loaded with Lumped Reactance………………………….….14.1 Slot antenna topology……………………………………………14.2 Simplified transmission line model……………………………15.3 Inductively-loaded slot antenna design…………………….……16.4 Capacitively-loaded slot antenna design………………………...18.5 Ground plane resonance and parametric study………..…………19.6 Miniaturized slot antenna for GPS application…………………23hapter 4. Varactor-Loaded Miniaturized Slot Antenna with Frequency Tunability…....58.1 Frequency tunability……………………………………………58.2 Antenna structure and dc bias network………………...……….58.3 Simulation and measurement results………….………………59hapter 5. Conclusion and Future Work……...……….74.1 Conclusion………….……………………………………………74.2 Future work……………………………………………………74eferences……………………………………………………………76ppendix………………………………………………………………78amp;#8195;ist of Figureshapter 2 ig. 2.1 Geometry of a microstrip-line-offset-fed slot antenna………..………………...9ig. 2.2 Microstrip-to-slotline transition………….……………………………………10ig. 2.3 Equivalent circuit for the transition of Fig. 2.2……………………………..…11ig. 2.4 Reduced equivalent circuit of Fig. 2.3…………………...……………………12ig. 2.5 Transformed equivalent circuit of Fig. 2.4………………..………...…………13hapter 3ig. 3.1 A λg /2 long, lossless transmission line shorted at both ends……………....25ig. 3.2 Geometry of half-wavelength slot antenna……………………………………26ig. 3.3 Measured and simulated input return losses of the half-wavelength slot antenna (1.6GHz)…………………...…………………………………….……………28ig. 3.4 Geometry of 5λg /16 length of inductively-loaded slot antenna…………...…29ig. 3.5 Measured and simulated input return losses of the 5λg /16 length of…...……… inductively-loaded slot antenna.…………………………………………..…31ig. 3.6(a) Measured and simulated E-plane radiation pattern of the prototype slot…… antenna (1.6 GHz).……………………………………………….………32ig. 3.6(b) Measured and simulated H-plane radiation pattern of the prototype slot…….. antenna (1.6 GHz)…………………………………………………………33ig. 3.7(a) Measured and simulated E-plane radiation pattern of the 5λg /16 length of….. inductively-loaded slot antenna (1.6 GHz)…………………………………34ig. 3.7(b) Measured and simulated H-plane radiation pattern of the 5λg /16 length of…. inductively-loaded slot antenna (1.6 GHz).………………………………...35ig. 3.8 Geometry of capacitively-loaded slot antenna…………………...……………37ig. 3.9 Measured and simulated input return losses of the half-wavelength slot antenna (1.2 GHz)………………………………………………………………...……39ig. 3.10 Measured and simulated input return losses of the capacitively-loaded slot…... antenna…………………………………………………………………….…40ig. 3.11(a) Measured and simulated E-plane radiation pattern of the capactively-loaded slot antenna (0.9 GHz)………………………………………………….…41ig. 3.11(b) Measured and simulated H-plane radiation pattern of the capactively-loaded slot antenna (0.9 GHz)…………….………………………………………42ig. 3.12 Photograph of miniaturized prototype slot antenna………………………..44ig. 3.13 Measured and simulated input return losses of the capacitively-loaded miniaturized slot antenna…………………………………………………...46ig. 3.14(a) Measured and simulated E-plane radiation pattern of the capactively-loaded miniaturized slot antenna ……………………………………………….….47ig. 3.14(b) Measured and simulated H-plane radiation pattern of the capactively-loaded miniaturized slot antenna ……………………………………………….….48ig. 3.15 Input impedance versus frequency with the width (GW) of ground plane as parameter………………………………………………………………….49ig. 3.16 Simulated input return losses for different values of Lm………………….50ig. 3.17 De-embedded input impedance versus frequency with the length (GL) of ground plane as parameter………………………………………………51ig. 3.18 Coupling structure of the slot antenna and the ground plane……………52ig. 3.19 Geometry of miniaturized slot antenna for GPS application………………...53ig. 3.20 Measured and simulated input return losses of the miniaturized slot antenna..... for GPS application.........................................................................................55ig. 3.21(a) Measured and simulated E-plane radiation pattern of the miniaturized slot... antenna for GPS application (1.575 GHz)………………………………...56ig. 3.21(b) Measured and simulated H-plane radiation pattern of the miniaturized slot... antenna for GPS application (1.575 GHz)………………………………57hapter 4ig. 4.1 Geometry of varactor-loaded miniaturized slot antenna………………………62ig. 4.2. Photograph of miniaturized varactor-loaded prototype antenna……………64ig. 4.3 Simulated input return losses of the varactor-loaded miniaturized slot antenna for VDC = 0, 2, 4, 12, 20 V…………………………………………………...66ig. 4.4 Measured input return losses of the varactor-loaded miniaturized slot antenna for VDC = 0, 2, 4, 12, 20 V.…………………………………………………...67ig. 4.5 Measured input return losses of the varactor-loaded miniaturized slot antenna… for different bias voltages……………………………………………………..69ig. 4.6(a) Measured and simulated E-plane radiation pattern of the varactor-loaded…... miniaturized slot antenna for VDC = 12 V………………………………...70ig. 4.6(b) Measured and simulated E-plane radiation pattern of the varactor-loaded…... miniaturized slot antenna for VDC = 4 V………...………………………….71ig. 4.7(a) Measured and simulated H-plane radiation pattern of the varactor-loaded… miniaturized slot antenna for VDC = 12 V…………………………………..72ig. 4.7(b) Measured and simulated H-plane radiation pattern of the varactor-loaded miniaturized slot antenna for VDC = 4 V………...………….........................73amp;#8195;ist of Tableshapter 3able 3.1 Design parameters for half-wavelength slot antenna (1.6GHz)………….….27able 3.2 Design parameters for 5λg /16 long, inductively-loaded slot antenna……….30able 3.3 Design parameters for half-wavelength slot antenna (1.2 GHz)……….……36able 3.4 Design parameters for capacitively-loaded slot antenna…………………….38able 3.5 Initial design parameters for capacitively-loaded miniaturized slot antenna..43able 3.6 Design parameters for the antenna with SMA-to-microstrip transition feeding from the side…………………………………………………………………54hapter 4able 4.1 Design parameters for varactor-loaded miniaturized slot antenna……..……63able 4.2 Input impedance bandwidth versus VDC……………………………………..682859440 bytesapplication/pdfen-US微型化天線槽孔天線頻率可調Miniaturized antennasslot antennasreconfigurable antennasthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/188315/1/ntu-98-R96942065-1.pdf