Analysis, design, and construction of a broadband balun for coaxial‐to‐planar transmission lines

For microwave signals within the 0.5 to 10.5 GHz range, we present an integrated broadband balun that carries signals from coaxial cable to microstrip to parallel-plate line. We use this arrangement as the feed line for a broadband double-sided antenna, and this antenna feed is presented as an application of the integrated balun. In addition, we devise a testing method for the balun, which is demonstrated. Through this testing method, the transmission, reflection, and radiation losses associated with the balun are readily determined. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 501–504, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20679