微機電多層型平面濾波器之研製

Design and Fabrication of Micromachined Multilayer Planar Filter

指導教授 : 黃榮堂 、施勝雄 研究生 : 詹淑君  機電整合研究所 91年


摘要

  本論文旨在研究兩種多層型平面濾波器,設計的中心頻率為2.4GHz與5GHz,首先研究多層型平面濾波器之特性,採用介入損失函數法來設計,再利用電腦模擬軟體來分析結果,最後使用微機電技術與薄膜技術來完成加工製作與量測。
本文所設計之微波濾波器包含一對小於四分之一波長的步階阻抗型耦合線,而耦合線在一端為短路,另一端為開路。其上包含一輸出/輸入耦合電容與內部共振器耦合電容,並藉由耦合電容值與耦合線結構的調整可控制濾波器的頻率響應。
而兩種帶通濾波器分別選用陶瓷基板與矽基板當作基材,相對介電係數為9.5與11.9,在中心頻率為2.4GHz方面,量測結果中心頻率偏移了400MHz,反射損失為-18dB,插入損失為3dB,本實驗製作之濾波器其大小3.63mm*7.75mm*0.5mm。

ABSTRACT

  This paper is aimed to research two filters with center frequency equal to 2.4GHz and 5GHz which are designed as multilayer planar filter. At first, we study the characteristic of multilayer planar filter and design it by the Insertion Loss Method. Then we use computer aided simulation to simulate and analyze the results. Finally, the MEMS (Micro- Electro-Mechanical System) and thin film process are used to fabricate the filters.
The filters are composed with a pair of stepped impedance resonator coupling striplines whose length is less than quarter-wave length; coupling capacitor comprises input/output coupling capacitors, and inter-resonator coupling capacitors. The coupled striplines are shorted at one end and opened at the other end. By adjusting the coupling capacitance and structure of coupling striplines, the frequency response of the filters can be controlled well.
The two types of multilayer planar filters made up of Al2O3 and silicon substrate. Their relative permittivity is 9.5 and 11.9. In the center frequency of 2.4GHz, the measured result of this filter shifts 400MHz. The measured insertion loss in the passband is less than 3dB and return loss is about 18dB. The dimension of the filter is 3.63*7.75*0.5 mm.