This article presents the design and optimization of output matching network according to envelope for class F power amplifier (PA), which is to apply to envelope elimination and restoration (EER) transmitter.In this article, to increase the PAE of class F PA, which applies to EER transmitter, the varactor diode has been used on output matching network. As envelope changes, it optimizes constitution of harmonic trap that is short circuit in second‐harmonic and is open circuit in third‐harmonic. When drain voltage changes from 25 V to 30 V, some percentage is improved in the PAE. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1890–1893, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25335