本論文致力於實現合成傳輸線之相位可重置操作特性，在引入變容二極體進行調制下，使合成傳輸線具有相位可重置之傳輸響應。藉由此創新之合成傳輸線進行延伸整合，本論文成功設計並實現多款相位可重置天線陣列與元件，並於單一頻率下以相當低的直流功耗完成實驗驗證。
首先，本論文成功將變容二極體成功整合於合成傳輸線，使其可重置性可視為一射頻開關，並能操作於兩種操作模態:其一為傳統延遲線；其二為開路電路以隔絕訊號。基於此可重置傳輸線之特性，提出一串聯饋入槽孔天線陣列設計。該設計以可重置合成傳輸線取代原本開關二極體之功能，使天線可於 1 × 2 陣列、2 × 4 陣列、3 × 6 陣列間切換，並可控制其二維波束寬及天線增益。
再者，針對此可重置合成傳輸線更進一步之探討，可將其合成傳輸線等效為一位元相移器，實現了「相位可重置」合成傳輸線。藉由解析該相位可重置合成傳輸線之設計原理，使其於切換相位狀態過程中，同步改變其電氣長度但仍保有良好之特徵阻抗匹配。吾人以此合成傳輸線之特性進一步整合於一平面天線以實現天線場型的相位可重置性。透過改變相位可重置合成傳輸線之相位，以控制相對應的控制天線輻射體之電流分佈，使天線之主波束能指向平面方位的四種不同角度。本天線設計具有低成本、平面架構與極低之直流功率損耗等優勢，具有應用於下一世代行動通訊系統之商用潛力。
最終，乃將前述之相位可重置合成傳輸線，成功應用於實現一款低成本、低複雜度，且具有良好波束控制性與寬廣掃描範圍之波束切換系統。本論文提出之系統以標準4  4 之巴特勒矩陣為基礎，並捨棄傳統昂貴之商用相移器，改為串接使用前述相位可重置合成傳輸線，以用增加各輸出埠之漸進相位移的可控制性。本系統以1 W之直流功耗，可將主波束之切換方向擴增為16個，其等效半功率波束寬為118o，掃描範圍之增益為7至10 dBi，且波束寬內之增益漣波均小於0.9 dB，整體系統之P1dB, in 可達 31.2 dBm。
最終，由此相位可重置合成傳輸線之持續調變特性，成功設計一款創新之可重置功率分波器。此分波器的架構由兩個混合正交耦合器組成，並將兩組相位可重置合成傳輸線插入其中。藉由調整相位可重置合成傳輸線之相位差，此可重置功率分波器可任意調整其功率分配比由-39至29 dB並同時於輸出之兩埠之間有穩定的相位響應(0o and 180o)。吾人相信此設計所提供之功率分配比可調範圍為目前所有公開文獻中不曾達到的

Novel reconfigurable synthesized transmission lines, whose transmission characteristics are controlled by varactor diodes, are presented in this dissertation. By utilizing newly developed synthesized lines, a number of reconfigurable antenna and phased array designs were fulfilled and validated at a given frequency with very low dc-power consumption.
First of all, the varactor diode has been successfully integrated into a synthesized transmission line to enable the reconfigurability as an on/off RF switch. It is capable of serving as a segment of low-loss transmission line in one state, but turning to open-circuited in the other state for signal blockage. A planar microstrip series-fed slot array has been proposed for street-level base station applications by using the newly developed reconfigurable synthesized line (abbreviated as RSTL). By incorporating the RSTLs into the feed network of the slot array, the number of radiating elements can be controlled in a variety of fashions. The radiation beamwidth, as well as antenna gain, can hence be switched two dimensionally with a dc-power consumption of less than 1 W.
The design concept of the reconfigurable synthesized line is further studied and extended as a 1-bit phase shifter (hereafter named as phase reconfigurable synthesized transmission line (PRSTL)). The proposed PRSTL is able to switch its electrical length between two states while keeping the characteristic impedance of the line unaltered during the reconfiguration. It is then integrated into the feed network of the planar antenna to enable the pattern reconfigurability. By changing the phase of PRSTLs, the current distribution on the radiator is controlled accordingly; the antenna main radiation is hence pointed at four different angles in the azimuth plane. With the advantages of planar form, low cost, and extremely low dc power consumption, the proposed antenna can find applications in smart mobile communication systems.
Thirdly, also with the help of the newly developed PRSTL, a low-cost, low complexity beam-switching system with enhanced beam controllability and widen coverage has been proposed and demonstrated. Instead of using the high-cost commercial digital phase shifter, the PRSTLs are cascaded and attached to the output of a standard 4  4 Butler matrix to further switch the progressive phase shift of the beam-switching array. With the dc-power consumption less than 1 W, the new beam-switching system can provide up to 16 output beams with an equivalent half-power beamwidth of 118o and the gain varying from 7 to 10 dBi within the coverage. The gain ripple is less than 0.9 dB and the output P1dB reaches up 29.5 dBm.
Finally, the continuously tuning characteristic of the PRSTL is also carefully investigated and applied to design a new planar reconfigurable directional coupler. The topology of the proposed coupler consists of two hybrid quadrature couplers and two PRSTLs inserted in between. By tuning the phase difference between the two PRSTLs, the proposed directional coupler can arbitrary tuning the power division ratio from -39 to 29 dB with constant phase responses (0o and 180o) between two output ports. It is believed that tunable range of the power division ratio of the proposed coupler is the largest in the open literature.

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