整合帶通濾波器之天線與混成器

Abstract

本論文提出多種整合帶通濾波器之天線和混成器。其中多數之帶通濾波器架構採用以共振器和導納反轉器組成之共振器耦合式濾波器。導納反轉器以電磁耦合實現，故其結構十分緊密。在不增加電路面積之前題下，引入多種功能以及帶通濾波器之響應。濾波天線之特點優點亦多有討論。相較於同型態之天線，在本論文中證實濾波天線具有較優之通帶邊緣選擇性、更平坦之通帶輻射響應、更高之拒帶雜訊抑制，以及更寬之頻寬。 首先，本論文提出一系列濾波微帶天線。本研究提出一種微帶天線之新型邊緣饋入架構。其輻射金屬片以另一共振器透過電磁耦合激發，因此達成二階帶通濾波器響應。繼而提出之對稱式之濾波微帶天線，具有更高效能。結構之對稱性導致更純淨之輻射極化以及更高之通帶邊緣選擇性。此概念更延伸至微帶天線陣列，其中天線單元以及饋入網路(以巴倫和功率分配器組成)皆為帶通濾波器設計之一部分。 再者，本研究提出二種濾波倒L型天線。其一具有極簡的結構和易懂的等效電路，以致於十分容易設計和製造。另外提出之差動饋入濾波天線整合倒L型天線、匹配電路、帶通濾波器、以及巴倫。此設計可直接連接差動射頻積體電路，而不需外加額外被動電路元件。 最後，本文提出二種合成帶通濾波器之元件。其中濾波180度混成器，整合巴倫和功率分配器，隔離度以對稱和反對稱模態之抵消達成。而於濾波威金森功率分配器之設計中，以橫跨輸出埠之電阻達成高隔離度。

In this dissertation, several bandpass filter integrated antennas and hybrids are proposed. Most of the bandpass filter architectures is the coupled resonator type which is made of resonators and admittance inverters. These admittance inverters are realized by EM couplings that result in very compact structures. Bandpass filter responses and multiple additional functions are implanted without occupying any additional circuit area. Special features and advantages of the filtering antennas are discussed. Comparing with the well-matched antennas with the same antenna types, it is proven that the filtering antennas have the better band-edge selectivity, flatter passband radiation responses, higher out-of-band rejections, and generally wider bandwidths. First of all, a series of filtering microstrip patch antennas is discussed. A new gap-feed structure for the microstrip patch antenna is proposed. The radiating patch is excited by another resonator through EM couplings and therefore a two-stage coupled resonator bandpass filter response is achieved. Then a performance enhanced filtering microstrip patch antenna is introduced. Geometrical symmetry leads to the purer polarization and the higher band-edge selectivity. This idea is further extended to microstrip patch arrays. The feeding network, which consists of power dividers and baluns, together with the radiating patches, are served as parts of the bandpass filter design. Next, filtering inverted-L antennas are investigated. We present an extremely simple-structured filtering antenna. This filtering inverted-L antenna is simple to design and easy to build according to its straightforward equivalent circuit. Then, the differential-fed filtering antenna which integrates an inverted-L antenna, a matching circuit, a bandpass filter, and a balun, is proposed. This all-in-one design can be directly connected to an RFIC with a differential terminal without any additional passive components. Finally, two bandpass filter integrated components are exhibited. A compact filtering 180° hybrid, which integrates a balun and a power divider, is proposed. Isolation between ports is achieved by the cancellation of symmetric and anti-symmetric mode operations. Furthermore, a compact filtering Wilkinson power divider utilizing coupled resonators is presented. Output terminals are loaded resister for port isolation.