一种改进的超宽带平面巴伦

Design and improvement of a novel wideband planar balun

设计了一种改进的基于共面波导和带状线传输的超宽带平面巴伦.采用低介电常数材料作为介质基板,引入一段切比雪夫多节阻抗变换器,并改进了使共面波导两地等势的方式.这些措施有效地增加了工作带宽,降低了介质损耗.设计并制作了一种50Ω非平衡到100Ω平衡馈电转换的超宽带平面巴伦,在0.1～3GHz的频率范围内,测试得到的插入损耗小于1.5dB,输出端接匹配负载时电压驻波比小于2,实验结果和仿真结果吻合良好.

An ultra wideband（UWB） planar balun（balanced to unbalanced transformer） is designed based on Coplanar Waveguide（CPW） and coplanar strip（CPS）.The proposed balun is fabricated on a substrate with low dielectric constant.For this balun,one Chebyshev impedance transform section is inserted and the structure making the two grounds of CPW electrically equal is improved.By means of these methods,the operation bandwidth of the proposed balun is expanded,and the insertion loss becomes lower.An UWB planar balun,which can transform a 50Ω unbalanced input to the 100Ω balanced output,is designed and fabricated.The measured results indicate that the insertion loss of the balun is lower than 1.5 dB and the VSWR is lower than 2 when the match load is connected with output in the frequency range from 0.1 to 3GHz.The simulation and measurement results are in good agreement.