無線網路前級之濾波器設計

Abstract

在本篇論文中,我們將介紹符合WLAN使用之頻帶濾波器,及波道濾波器的設計流程。並且根據系統規範的要求,訂定所需的濾波器規格,以壓抑頻帶外部干擾信號的能量,以及相鄰波道的能量。 在高頻的帶通濾波器設計中,我們選擇以低溫共燒陶瓷為基板,並以四分之一波長的離散條狀導線為架構,以完成設計工作在2400MHz~2483MHz的帶通濾波器。此外,並以UMC 0.25mm的製程,加上智森科技所提供的電子元件模型,完成設計一個0~11MHz輸入/輸出皆為差動方式的低通濾波器模擬,以做為波道能量選擇之用。 最後,我們將以高頻帶通濾波器的量測結果,再加上所有可能造成誤差的變數,輔以模擬軟體(Sonnet)一一加以驗證,以找出造成誤差的原因,以及未來改進的方向。

In the thesis, we discuss a band pass filter and a channel selection filter to fit in with WLAN 802.11A/B standard. In this specification requirement we need to calculate a suppression power ratio for an external filter to suppress the out-of-band and adjacent channel power effect. We select the LTCC substrate and use interdigital structure to design a RF BPF with the pass band region of 2400MHz to 2483MHz. In the Gm-C filter design, we use UMC 0.25mm process and Giga-Solution’s model to achieve the simulation of a 0 to 11MHz pass band filter with fully differential input/output structure. Eventually we measure the BPF and re-simulate it with different variants by Sonnet. Then some useful results that cause inaccuracy will be gotten. And I will summarize them in the future improvement.