操作在1.7-2.7千兆赫茲、具頻寬與傳輸零點控制之小型化二階可調式帶通濾波器

Abstract

本論文演示了設計二階可調式帶通濾波器的方法，具有可以調整操作頻率，頻寬大小，傳輸零點位置控制的效果。傳統濾波器在不同需求下需要不同電路來實現系統，如操作頻率、頻寬大小需有特定規格之類似電路所實現。而在加入可調式電容後，將所有相同規格不同需求之電路全部整合，透過提供電壓來改變可變電容的電容值，來做出不同操作頻率和頻寬的改變，可僅以單一電路便符合不同情況下所需要的功能。另外源負載耦合提供了本文中濾波器能有更為良好的選擇度及對稱性，在表現方面更為出色。 而在多加了傳輸零點控制的機制後，能使得通帶鄰近處的雜訊能更為有效的抑制，且透過可變電容值的不同，傳輸零點位置移動變成可行，而可以將傳輸零點移動到雜訊較為明顯的地方，更有效地抑制雜訊。而在操作頻率和頻寬控制機制保留下，多加了傳輸零點的控制，將使得此濾波器自由度更為擴大。而本文以較為簡單二階濾波器結構便能實現多種功能，也讓大大簡化電路複雜度，亦具有高度的發展性。

In this thesis, the design method two-pole tunable bandpass filter is presented, with tuning center frequency, bandwidth and transmission zero control. Conventional filter which requires different circuits to realize system in different circumstances, its center frequency and bandwidth require specific similar circuit to realize. Since loading tunable capacitor, it combines all different requirements but similar standard circuits. By the way of improving voltage can change tunable capacitor’s capacitance, can make the center frequency and bandwidth change. It can meet the all requirements by only one circuit. Furthermore, source-load coupling improves the filter have better selectivity and synthesized in this thesis, and make it more outstanding. Since adding the network of transmission zero control, the noise neighboring the passband can be significantly rejected. Changing the varactor’s capacitance, the transmission zeroes’ location is movable, and can move the transmission zeroes to the noise which is obvious to significantly reject it. With remaining the function of center frequency tuning and bandwidth control, the adding transmission zero control will make this filter more freely. In this thesis, more simply two-pole filter structure can fill several functions. It can widely simple circuit’s complexity and have better development.