AbstractIn this article, propagation delay matched CMOS frequency doubler for L‐band application is proposed. Schmitt trigger and voltage controlled delay line compensates duty cycle error and propagation delay mismatching that are induced as the frequency of operation is increased. As a consequence, unwanted harmonic components suppression is greatly improved for higher frequency of operation. CMOS frequency doubler is designed at the input fundamental frequency (f0) of 1.15 GHz and fabricated with TSMC 0.18 μm CMOS process. Measured output power at the doubled frequency (2f0) is 2.67 dBm for the input power of 0 dBm. The amount of harmonic suppression for f0, 3f0, and 4f0 are 43.65, 38.65, and 35.59 dB, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1729–1732, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24420