Complex shaped periodic corrugations for broadband Bull’s Eye antennas

Periodically corrugated metallic antennas have been developed in recent years from microwave to THz frequencies, due to their advantages of highly directive radiation patterns, low profile and ease of fabrication. However, the limited gain bandwidth of such antennas remains one of their inherent disadvantages. In terms of design, the majority of the existing implementations in literature utilize the standard rectangular shaped corrugated unit cell. In this paper, we propose novel complex shaped corrugated unit cells that produce a broadband performance when assembled in a periodic configuration. Two broadband prototypes are presented at the Ku frequency band that are formed of hybrid shaped corrugations. The first prototype of six periodic rings achieves, for the first time, a flat gain simulated response with a maximum value of 15.7 dBi, 1-dB gain bandwidth of 16.4%, and an extended 3-dB gain bandwidth of 19.64%. The second novel prototype of five rings achieves an enhanced 3-dB gain bandwidth of 15.2% and maximum gain of 18.1 dBi.

A High Flatness Gain Subsisting of Cascaded EDFA-TDFA Hybrid Optical Amplifier For Super Dense Wavelength Division Multiplexing System

Flat gain with least noise figure (NF) is the backbone feature of super dense wavelength division multiplexing (SD-WDM) system. It indicates the good amplification in terms of high-quality factor, lowest bit error rate, and good rating output power. But in this paper, we have mainly focused on characteristics of proposed EDFA-TDFA hybrid optical amplifier (HOA) in terms of flat gain and noise figure for C-Band. Evaluation has done for 400 x 2.455 Gb/s SD-WDM system with channel spacing of 0.8 nm. Moreover, effect of proposed HOA also observed with displacement of channel wavelength for evaluating the impact of different set of HOA for analysis the same characteristics.