Cladding mode coupling suppression in hole‐assisted fiber BRAGG gratings

Abstract

model is feasible and can be applied to design such kind of a CPW-fed antenna. Furthermore, as previously described in this study, varying the slot width s will significantly affect the resonant performance of the proposed antenna. Thus, in contrast to the effects of s to the impedance matching, the effects of the lumped elements of the equivalent circuit model to the impedance matching have also been investigated. The results were also plotted in Figure 8 and show that very little difference exists between the simulated and modeled data. Clearly, the effects of impedance matching caused from varying the slot width s can be closely represented by properly adjusting the values of the capacitance C p and resistance R p . This is vital for concluding that the proposed circuit model is accurate and adequate for design purposes and can therefore be used for understanding the basic radiation phenomena of such kind of slotted CPW-fed antennas. CONCLUSIONSA compact low-profile CPW-fed U-shaped patch monopole antenna suitable for use in the 5.8 GHz RFID system has been proposed and implemented. With the insert of a symmetrical folded slot to the patch, the proposed antenna can be designed to excite at 5.8 GHz band with good antenna characteristics but has only 15 ϫ 10 mm 2 in antenna size. The antenna is mechanically robust and easy to fabricate and integrate with the application-specific circuit. This design is not only suitable for use in the RFID systems but is also applicable to the WLAN 5.8 GHz communication systems. Except for presenting the simulated and measured results, an equivalent circuit model was also established and provided a physical insight to account for the impedance matching of this kind of antenna.

Mechanically induced long-period fiber grating in side-hole single-mode fiber for temperature and refractive sensing

“…So the resonant wavelength shift increased as the liquid refractive index increased. The effective indices of the cladding modes became bigger gradually when the effective index of the liquid inside the two air holes of the cladding region increased [20]. So the resonant wavelength had a blue shift as seen in Eq.…”

“…(1). Moreover, the radii of the side holes and the distance between the core and the side hole can change the effective indices of the cladding modes, so the effective indices of cladding modes are smaller compared with smaller radii of side holes and longer distance between the core the side hole [20][21][22]. The resonant wavelength of a MLPG is anticipated to be varied with temperature because of the temperature dependence of the modes' effective indices.…”