AbstractSimulated and measured results of a diplexing feed network for a wideband dual‐frequency stacked microstrip patch antenna are presented. The microstrip feed network is easy to design and consists of a T‐junction and a single decoupling resonator for each frequency band. The return loss in each of the frequency bands is better than 10 dB, over a better than 10% bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 100–102, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10686