Studying of Unequal Power Branch-Line Couplers with Unequal Length

• Main Authors: Kuo-cheng Cho, 卓國程
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/34592142544161567729

碩士 === 逢甲大學 === 資訊電機工程碩士在職專班 === 99 === Abstract The application of Branch-Line Coupler in communication system field is tremendous as well as it has characteristics of phase variation and power distribution; thus two kinds of unequal power Branch-Line couplers with unequal length are proposed in this article. The first structure is a unequal power Branch-Line couplers with unequal length of 4dB; and the second type is that of a 5dB. Both two types of the unequal power Branch-Line couplers with unequal length as stated above come with characteristics of power distribution. The working band of unequal power Branch-Line couplers with unequal length in design is at 0.9GHz by using FR4 glass fiber double-sided board with designing parameters of (tanδ= 0.022 εr = 4.7 ; metal thickness = 0.02mm ; thickness=0.8mm). Utilizing Sonnet simulator in simulating the circuit and measured by network analyzer, finally compare the data result of the simulated circuit of its S11 vs. S41≦-15dB；the phase variation of S21-S31conforms to 90°± 1°; and if the output power of S21-S31 turns out to have characteristics of unequal power distribution in proportion. In this article, the advantages of two unequal power Branch-Line couplers with unequal length of 4dB and 5dB were found not only have the characteristics of power distribution, but also their linewidth are apparently much wider than that of the 3dB''s that it is able to accomplish the circuit without using lumped element and jumper, which is broadly used in the microwave circuit system.