Canonical型式帶通濾波器

Abstract

本論文中我們提出了利用髮夾式諧振腔的微帶線交錯耦合結構。藉由正交錯耦合或負交錯耦合的組合，在複數平面上得到傳輸零點。進而控制讓傳輸零點落於實數頻率軸來達成增加禁帶(Stopband)的衰減，讓傳輸零點落於虛數頻率軸來達成改善通帶(Passband)的傳輸延遲。利用傳輸零點在複數平面的位置反應在響應上的特性，我們提出了Canonical型式的濾波器，而我們選擇了現今最熱門的通訊產品之一的無線區域網路所應用的頻率2.4GHz到2.5GHz這個頻帶當作濾波器設計的頻帶。 在此論文的最後，完成了三種不同的Canonical濾波器及一個柴比契夫濾波器。分別將他們的結果相互作比較，可以看到電路的量測結果及模擬的結果相當符合我們所預期的。

In this paper, we used the hairpin cross-coupled resonators and utilized the characteristic of cross coupling while the location of finite transmission zeros at complex frequency plane. It increases the stop band attenuation while the finite transmission located at real frequency axis and flatted the pass band group delay while the finite transmission zeros located at imaginary frequency axis. We bring up the canonical form comb line filter by using the characteristic of location of finite transmission zeros at complex frequency plane. Now, we chosen the frequency (2.4 GHz to 2.5 GHz) of one of most popularization in wireless communication – wireless LAN to design canonical filter. At the end of this paper, we design three kinds of canonical filters and a Chebyshev filter. As shown the result and comparison in this paper, it quite meets the expectations from the result of simulation and measurement.