A double frequency 180° lumped‐element hybrid

In this letter design formulas for the development of an unusual 180° hybrid working at two distinct frequencies are provided. In particular, the design formulas of a lumped-element rat race are considered. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 247–251, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10288