We propose and demonstrate a C band Erbium doped fiber amplifier (EDFA) using amplified spontaneous emission (ASE) power peaking selective and feedback to achieve highly stabilized and wide dynamic range gain clamping performances. The gain of 16.20 ± 0.13 dB is obtained with the input signal power dynamic range of 30 dB and the maximum noise figure (NF) was 6.6 dB with the input signal power from -35 to -10 dBm. To investigate the gain variation for the probe signals, we applied a saturation tone signal to simulate 16 channel DWDM signals as it is added (dropped) into (from) EDFA. The gain variation of the proposed scheme at a appropriate ring cavity loss (VOA = 5 dB) is less than 0.13 dB for the input signal power from -35 to -5 dBm and wavelength from 1530 to 1564 nm.
It is observed from the Eq. (1) that the length parameter "t" is nearly equal to k/4 for all tuning frequencies (6.096-3.51 GHz). Maximum difference for the calculation of "t" from the Eq. (1) and Table 1 is about 0.5 mm, which is very small. Fabricated prototypes of the Antenna 3 (for t 5 13.25 mm and t 5 21.6 mm) are shown in Figures 3(a)-3(c). Measurement results for reflection coefficient are carried out using VNA (Agilent N5 230A). Comparisons between simulated and measured reflection coefficient are shown in Figure 4. Measured resonant frequencies are 3.486 GHz for the antenna with t 5 21.6 mm [Figs. 3(a) and 3(c)] and 5.664 GHz for the antenna with t 5 13.25 mm [Figs. 3(a) and 3(b)]. Measured 210 dB impedance bandwidths are about 180 MHz for t 5 21.6 mm and 420 MHz for t 5 13.25 mm. However, the discrepancy between the measured and simulated results is (about 0.85% for t 5 21.6 mm and 3.1% for t 5 13.25 mm in resonance frequencies) due to the effect of soldering of SMA connector and fabrication tolerance. Measured radiation patterns at 5.664 and 3.486 GHz are shown in Figures 5(a) and 5(b). Resolution of the measurement is 10 for h and u of the spherical coordinate systems. The directions of the maximum radiations for E-plane (u 5 0 ) copolarization are 0 and 260 at 5.664 GHz [Fig. 5(a)]. At 3.486 GHz, the directions of the E-plane copolarization broadside patterns are seen in 16-88 and 254 [Fig. 5(b)]. The antenna with t 5 21.6 mm, shows its minimum E-plane copolarization gain in 210 (blind point) direction. The cross polarization level at 5.664 GHz [ Fig. 5(a)] is less than 221 dB. However, at lower frequency (3.486 GHz), the antenna cross polarization level is increased (about 211 dB) due to the unsymmetrical voltage distribution between the two radiating edges of the patch. The gain of the antenna for t 5 13.25 mm is 2.16 dB and t 5 21.6 mm is 1.13 dB.
CONCLUSIONA compact bandwidth enhanced microstrip antenna with frequency tuning capability has been proposed in this article. Parametric study of the RGS was carried out and results were validated by the measurement results. It has been observed that the ground slot length is nearly equal to the quarter wavelength of the proposed antenna over the whole tuning frequencies (6.096-3.51 GHz) and, thus, size reduction is obtained. The tuning bandwidth of the proposed antenna is about 53.84%. The antenna can also operate in IEEE 802.11a WLAN band (5.12-5.86 GHz) with bandwidth of about 13.48% and compactness of 53.67%.ABSTRACT: In this study, optical upconverted microwave frequency generation was experimentally demonstrated using a frequency quadrupling technique based on two types of baseband signal modulation in a radio-over-fiber (RoF) system. The measured results revealed that an error-free transmission could be achieved without causing the periodic power fading affect, and that clear eye diagrams were obtained after a 20-km transmission by using baseband/RF mixed-signal external modulation. The proposed method is a feasible technique for generating a 622 ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.