Design and improvement of a novel wideband planar balun

doi:10.7523/j.issn.2095-6134.2010.4.011

Abstract

Abstract:

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.

Key words: balun, ultra wideband (UWB), coplanar waveguide (CPW), coplanar strip (CPS)

CLC Number:

TN957

WU Bing-Heng, JI Yi-Cai, FANG Guang-You. Design and improvement of a novel wideband planar balun[J]. , 2010, 27(4): 507-511.

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