互补传输线实现小型化平面巴伦

Planar Balun with Complementary Conducting-Strip Transmission Line

应用一种新型的互补传输线Complementary-Conducting-Strip Transmission Line(CCS TL)实现了简单结构的平面无耦合巴伦(balun),在保证性能的前提下极大地缩小了电路尺寸,便于紧凑化集成。整个电路在0.127mm厚度的Arlon 880基片上实现,平面面积为8mm×6mm,约占传统微带线实现相同电路面积的五分之一。电路的中心频率为7.5GHz,带宽为40%(6GHz-9GHz),带内各端口回波损耗在-10dB以下,平衡端口隔离度在-15dB以下,平衡端口输出幅度不平衡度在±0.5dB以内,实测结果符合理论预期。

This paper presents a compacted planar balun using a novel transmission line so-called complementary-conducting-strip transmission line( CCS TL). Under the premise of good performances,the circuit size is greatly reduced. Balun is realized in Arlon 880 substrate with the thickness of 127μm. The effective area of the prototype is 8mm × 6mm,about one fifth of the area of original microstrip( MS) design. The center frequency of this design is 7. 5GHz. Measured results show that-10dB return loss of the unbalanced port and the two balanced ports has been achieved across the bandwidth from 6 GHz to 9 GHz. Within the operation band,the balanced ports isolation is below-15 dB. The measured amplitude difference between the two balanced ports are within 0. 5 dB,over the operating frequency band. Good agreement between simulation and measurement has been achieved.