are presented in Figure 8. It is seen that the radiation patterns of designed antenna are omnidirectional in H-plane and directive in E-plane. Measured results of proposed antenna shows that the antenna is suitable for UWB applications. Also, stable radiation characteristics are shown, which is necessary for UWB antennas.To verify the capability of the proposed antenna to operate as an UWB antenna, the designed antenna should have a consistent group delay. The group delay of the dual-band notch UWB antenna can be obtained from s g ¼ db/dx, where b is the phase of the transfer function of the antenna. Figure 9 shows the simulation results of the group delay for the face-to-face configuration. It is obvious that the proposed dual-band notch antenna has a consistent group delay, which can be used for UWB applications. A photograph of the fabricated fork-shaped antenna with dual-band notch characteristics is displayed in Figure 10.
CONCLUSIONSA printed wide slot antenna is proposed and implemented for UWB applications. The overall size of antenna is 28 Â 32 Â 1 mm 3 . The antenna, compact and small, has minimum design parameters, which have been investigated for optimal design. By using protrudent open-circuit stubs at appropriate positions, sin-gle-and dual-band notch antenna is also realized with good out of band performance. The operation bandwidth of proposed antenna covers the frequency band from 2.4 to 10 GHz. Both simulated and measured results suggest that the proposed antenna is suitable for UWB communication applications and at the same time operates as a band stop with 5.7-6 GHz (WLAN) and 3.3-3.9 GHz (WiMAX) systems.ABSTRACT: A simple intensity modulation based displacement sensor using fiber optic coupler probe is proposed and demonstrated for sensing the concentration of alcohol solution. The intensity of light reduces almost linearly with the displacement and the sensitivity of the Figure 9 Group delay of dual-band notch antenna. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]ABSTRACT: The area of a ultra high frequency (UHF) patch antenna was reduced 80% by embedding high permittivity plugs in the antenna substrate. It is shown that a nonuniform distribution of plugs provides solutions for such problems of the miniaturized antennas as impedance matching and achieving circular polarization of the signal.