超寬頻次諧波正交中頻訊號混頻器與鏡像消除混頻器

Abstract

無線通訊中的超寬頻系統，逐漸演變成為一個熱門並且重要的通訊系統，超寬頻系統的特性在於擁有很大的頻寬及快速的傳輸速率。消除超寬頻系統混頻器之中的鏡像訊號，是提昇系統性能的有效方法。而在超寬頻系統混頻器當中，超寬頻90度耦合器是最重要的元件。

本論文的前半段，我們會使用多節式架構來實現一個超寬頻的90度耦合器，其中耦合強度最強的部份，會利用垂直式耦合器來達成。能增進耦合器反射損耗與隔絕性效能的補償架構也會在此篇論文中討論。

本論文的後半段會介紹兩種混頻器。第一種是兩個輸出埠之間會有90度相位差的次諧波正交中頻訊號混頻器，第二種則是具有消除鏡像訊號功能的次諧波混頻器。較小的面積跟使用較少的元件數，是這兩種混頻器的優點。

The UWB system is receiving growing attention as an important communication system for wireless communication. The characteristics of UWB system are the ultra wide bandwidth and its high data rate transmission. In order to obtain a better performance of the UWB system, an UWB mixer with the function of rejecting image signal is needed. An ultra broadband directional coupler is the most important element of the UWB mixer due to the large bandwidth.

In first part of this thesis, we will utilize multisection structure to perform an UWB coupler. The most tightly coupling section of the multisection coupler is fabricated by VIP structure. The compensated stub, which can improve return loss and isolation of this coupler, is presented in this thesis.

In the second part of this thesis, two kinds of mixers are discussed. The first one is a subharmonic quadrature-IF mixer, the phase difference between two output ports is 90 degree. The second one is a subharmonic image rejection mixer. All the mixers mentioned above have the benefits of small layout area and fewer elements.