本論文提出兩個小型化的微波電路元件，第一個微波元件為利用電感補償相移器之共平面波導至矩形金屬波導的轉接器，第二個微波元件為利用截角補丁天線之圓型金屬波導極化器。
在第二章中，我們首先設計一個利用180度相移器之共平面波導至矩形波導轉接電路，此電路小於-15 dB反射系數操作頻寬為8.05 GHz ~12.18 GHz，比例頻寬38.8%，幾乎涵蓋整個X-band。進一步的，我們使用電感補償之技術將180度相移器的尺寸更加縮小，總電路尺寸達5.9×10.16×0.8 mm3，同時15 dB反射系數操作頻寬提升為8.05 GHz ~12.38 GHz。為了驗證模擬結果，利用電感補償相移器之共平面波導至矩形金屬波導的轉接器被背對背的連接起來且量測，量測的數據與模擬有良好一致性。

在第三章中，我們首先提出一個利用矩形補丁實現之微帶線至圓形金屬波導轉接，此轉接非常的小，因為矩形補丁僅放在距離圓型波導短路面2.68 mm處。接著我們提出一個利用截角補丁天線之圓型金屬波導極化器，此極化器在9.65 GHz時軸比為0.002 dB、相差達到-90.97度，且在9.65 GHz附近反射係數皆小於-20 dB。此外，我們提出的極化器不需要在金屬波導上做複雜的加工，並且使用微帶線饋入使得此極化器更容易與其他的平面電路結合。為了驗證模擬結果，圓形波導的末端被打開且量測，量測與模擬的結果得到良好一致性。

In this discourse, two compact microwave components are proposed, which include the compact and broadband CPW-to-RWG transition using the inductance compensated phase shifter and the compact microstrip-fed CWG polarizer using the corner-truncated patch. The characteristics of each of them are described below.

In chapter 2, firstly, a CPW-to-RWG transition using the half-wavelength phase shifter is introduced. The transition has a broadband response in which the frequency range of the -15-dB reflection coefficient covers from 8.05 GHz to 12.18 GHz (FBW = 38.8%), almost encompassing the whole X-band (8.2-12.4 GHz). In order to reduce the size of the transition, the inductance-compensated phase shifter is used to replace the half-wavelength phase shifter, resulting in a compact and broadband CPW-to-RWG transition using the inductance-compensated phase shifter. The size of transition is 5.9×10.16×0.8 mm3 and the frequency range, for which the reflection coefficient is smaller than -15 dB, covers from 8.05 GHz to 12.38 GHz, estimating to be 42.04%. In order to verify the simulation results, two CPW-to-RWG transitions using the inductance-compensated phase shifter are back-to-back connected, fabricated, and measured. The measurement and simulation results are in reasonable agreement, which verifies our design.
In chapter 3, firstly, a MSL-to-CWG transition using the rectangular patch is introduced. The rectangular patch is placed 2.68 mm (0.043 λg) away from the short-circuited plane of the CWG port, making the transition very compact. Secondly, a MSL-fed CWG polarizer using the corner-truncated patch is proposed. The proposed polarizer has an axial ratio of 0.002 dB and a phase difference of -90.97° at 9.65 GHz. The reflection coefficient is below -20 dB around the center frequency 9.65 GHz. In additional, the proposed polarizer needs no complex manufacturing process on the waveguide. Moreover, since the polarizer is fed by the microstrip line, it would be easy to integrate with other planar circuits. In order to verify the simulation results, the CWG port of the MSL-fed CWG polarizer using the corner-truncated patch is opened, simulated and measured. The simulation and measurement results are in good agreement.

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