AbstractCompared with the conventional log‐periodic balun, the design of a symmetric log‐periodic balun can provide better performance over the entire designed band. A novel ultra‐wideband (UWB) balun with 3–6 GHz passband is demonstrated for UWB applications. The problems of fabrication and measurement of the conventional log‐periodic balun operated at higher frequency problems can be further improved. The magnitude and phase difference between two output ports are kept balancing at higher band edge portion. The measured amplitude imbalance is about ±1.1 dB with a corresponding phase difference about ±4°. The bandwidth of the balun is around 70%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 947–948, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23264