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UWB Slot Antenna In the 3-9GHz band

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Recently an emerging ultra-wide band (UWB) technology is on development. It requires hard design specifications for antennas over a very wide bandwidth. U.S. Federal Communication Commission (FCC) defines UWB as higher than 20% fractional instantaneous bandwidth. Short-pulse UWB technology is applied in communication, radar and precision radiolocation. | UWB SLOT ANTENNA IN THE 3-9 GHZ BAND José Manuel Pidre Mosquera María Vera Isasa. Dpto. Teoría de la Señal y Comunicaciones. Universidad de Vigo. Spain. http www.grp.tsc.uvigo.es Introduction Recently an emerging ultra-wide band UWB technology is on development. It requires hard design specifications for antennas over a very wide bandwidth. U.S. Federal Communication Commission FCC defines UWB as higher than 20 fractional instantaneous bandwidth. Short-pulse UWB technology is applied in communication radar and precision radiolocation 1 One of last applications for UWB technology is breast tumor detection 2 In this detection system the antenna has to work in frequencies ranging from 3 to 9GHz. In addition the impulse response has to be short constant radiation pattern over the band and low return losses. One of the most promising antennas that can meet these design goals is the ultra-wideband magnetic antenna 3 4 The behavior of this antenna in the 3-9 GHz range is presented in this paper. An V-model and the use of a back-absorber layer in order to improve its performance is analyzed. A prototype has been built and measured. UWB Magnetic slot antenna The antenna consists of a leaf-shaped slot excited across the gap as can be seen in figure 1. The radiated fields are orthogonally polarized to the longitudinal slot axis. Figure 1. UWB Magnetic slot antenna. Original flat configuration right and proposed configuration in the left 0-7803-8883-6 05 20.00 2005 IEEE JVO Authorized licensed use limited to Phan Phuong. Downloaded on January 14 2010 at 03 11 from IEEE Xpl In 3 is defined the width of the slot w as we move across longitudinal slot axis 1 Â f nl Y f id 1 w cos 1 - cos - 4 UJL UJ. 1 where ko is the wavelength in the center frequency. A deeper analysis of equation 1 reveals this ratio between maximum slot width W and slot length L W 1 0.0625 L 16 2 The antenna was evaluated using the software packages IE3D and XFDTD. IE3D is a commercial method of moments code 5