source. The frequency of signal depends on the wavelength difference of two lasers. By tuning the wavelength of lasers, we can achieve any frequency microwave signal which we need. ACKNOWLEDGMENTS

A novel double‐printed rectangular patch dipole antenna with a band‐notched function suitable for UWB application is presented and investigated in this article. The band‐notched characteristic is achieved by connecting L‐shaped strips to the antenna rather than inserting slot to the antenna. The measured results show that the frequency band of VSWR < 2 covers 3.1 to 10.6 GHz UWB band, whereas the notched‐frequency range is 5.05–6.1 GHz which covers 5GHz WLAN band of 5.15–5.825 GHz. Transfer function and time domain characteristics are also studied in this article. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 269–272, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24921