4 research outputs found
Micro-Electro-Mechanical Systems (MEMS) Integrated Frequency Reconfigurable Antenna
Get PDFIn this paper, the design, analysis, and characterization of reconfigurable antennas based on radio frequency micro-electro-mechanical systems (RF MEMS) operating in the United States\u27 public safety (PS) bands are presented. The design methodology of these antennas, which are different from the normal antenna design, is also reported. In this thesis, two electrically small reconfigurable antenna designs have been presented, with two and three modes of operation, and central frequencies of 718 and 4960 MHz and of 857,809 and 4960 MHz, respectively. The maximum frequency tunable ratio achieved in these designs is 7. The recongurability between the modes is achieved by one and three RF MEMS switches in all three designs. These switches enable a change in the length of the current flow path, thereby changing the resonance frequencies. The measurement results for impedance and radiation characteristics of the fabricated antennas prototypes are also presented, and agree reasonably well with the simulations results from An-soft HFSS
Challenges Affecting the Implementation of £50 Million In-Service Training Program for English Teachers in Bangladesh
No full textNumerous donor-sponsored in-service training programs have been operated in Bangladesh for English language teachers. EIA was the last donor-funded project that incorporated school-based training. It claimed to acquaint teachers with technology coupled with a lot of interactive activities to be incorporated in the classroom. The aim of the study was to identify the challenges faced by the secondary-school English language teachers in incorporating the elements learned in EIA training into their classroom practices and to identify the solutions to overcome the challenges. The present study undertook reflective theory developed by Wallace (1991). To conduct this study, semi-structured interview with the teachers and semi-structured classroom observation were carried out. Teachers reported some issues that potentially precluded them from employing different activities in their classrooms. In addition, teachers elicited suggestions to overcome the challenges. The interview data were organized thematically. This study was intended as an eye opener for the policy makers in the small states
