射頻系統封裝模組暨縮小化雙頻印刷天線設計

Abstract

本篇論文前段提出三個應用於802.11b之射頻前端模組，模組一之接放和發射路徑均包含了一個天線分集開關(diversity switch)、一個收發切換開關(T/R switch)及一個帶通濾波器，模組二則是在發射路徑將帶通濾波器改為低通瀘波器，以減少發射路徑整體的輸入損耗，模組三則是將模組一的結構在發射端再加上一個功率放大器。此三個模組均利用低溫共燒陶瓷(LTCC)為載板，將功率放大器、天線分集開關(diversity switch)及放發切換開關(T/R switch)放罝於載板之上，濾波器和電路匹配所需之電容和電感則設計於載板之內。後段則是提出兩種不同架構的倒F天線，首先是利用螺旋繞線的方式，再者是將耦合線當作天線的饋入，兩者皆可縮小天線尺寸並產生雙頻，且螺旋繞線之結構在印刷電路板及低溫共燒陶瓷上均獲得驗證。實作的結果也顯示了此兩種結構可以輕易設計在所需要的頻段，比起傳統的印刷倒F型天線也可以縮小約70%及47%，且場型也具有全向性場型的特性。

In front of this thesis, three RF front end-module (FEM) based on LTCC (low temperature co-fire ceramics) under 802.11b specification is designed. The first FEM contains a diversity switch, a T/R switch and a band-pass filter in both receive and transmit path. The second FEM changes the band-pass filter in the first FEM into low-pass filter in transmit path to improve the total insertion loss. The third FEM includes a power amplifier than the first FEM. They put power amplifier, diversity switch and T/R switch on the top layer of LTCC substrate and band-pass filter, capacitors and inductors of the matching circuit in it. The second part of this thesis, two different inverted F antenna structure are proposed. The first antenna uses spiral line, and the second utilizes couple line as its feed. They are both with miniaturized size, operated in dual frequencies, and implemented by printed circuit board and LTCC. The measured results also reveal that they which have less size than the conventional inverted F antenna and omni-directional pattern can easily operated in the designed frequency.