V頻段基板整合波導雙工器設計

Abstract

本論文將製作V 頻段基板整合波導頻率雙工器，使用電感性金屬柱耦合濾波器架構來實現帶通濾波器，中間以微帶線T形結來完成頻率雙工器，本論文將使用兩種方式來提高隔絕度(Isolation)，第一種為在帶通濾波器後面加上帶止濾波器抑制不需要頻帶的訊號，第二種為使用三階交錯耦合濾波器來實現頻率雙工器，三階交錯耦合濾波器能將傳輸零點拉至有限頻率，增加隔絕度。第一種其優點為抑制效果好，較不受頻帶相近而影響，缺點為電路面基增大，第二種其優點為改變架構面積不會變大，缺點為兩中心頻無法設計太近，傳輸零點離中心頻越近效果越差。 本論文將設計兩種不同頻率的雙工器，一為操作在中心頻60 GHz與67 GHz的頻率雙工器，一為操作在中心頻63 GHz與67 GHz的頻率雙工器，目的為探討中心頻遠近對於這兩種提高隔絕度方法之可行性。 電路實作上將使用兩種板材，一為基板厚度10 mil，介電常數2.2的 Rogers RT- Duroid 5880TM板材、另一為基板厚度10 mil，介電常數3.66的Rogers RO4350TM板材，Rogers RT- Duroid 5880TM板材使用設計之轉換器與金屬矩形波導管連接進行量測。

The design of V-band Substrate Integrated Waveguide (SIW) micrrostrip T-junction duplexer is presented in this thesis. Two inductive-post coupled channel filters are combined with microstrip T-junction. Two structures are proposed to improvement the isolation. First, we suppress unwanted signal by using a bandstop filter. The adventage of this method is that even if the frequencies of two channel filters are close to each other the method is still valid. Second, we replace the Chebyshev channel filter with a 3rd order cross-coupled filter that a transmission zero near the edge of the passband is created. The adventage of this method is the small size but as the channels closing to each other the suppression is not as good as the first method. To explore the relation between isolation and the distance of two center frequencies, two duplexers with center frequency of 60 GHz, 67 GHz and 63 GHz, 67 GHz are studied. The circuits are fabricated using two kinds of substrates. One is Rogers RT- Duroid 5880TM substrate with thickness of 10 mil, dielectric constant of 2.2, the other one is Rogers RO4350TM substrate with 10 mil, dielectric constant of 3.66. The circuits using Rogers RT- Duroid 5880TM substrate are connected to SIW to a specially designed rectangular waveguide transition and measured by vector network analyzer.