Mohammad Nurunnabi Mollah

Investigation on EBG structures: A critical analysis to optimize the performance of asymmetric couple-line bandpass filter

EBGSs, Electromagnetic Band Gap Structures, have been developed into the most prominent framework by virtue of their superior efficacy, less intricacy in fabrication, and unified integration with the monolithic microwave integrated circuits (MMICs). In this letter, a certain number of advanced designs of EBGS are introduced and characterized with some rigorous parametric studies. This epistle regards the planar-EBG frameworks in the fashion of conventional uniform circular, square, and annular ring patterns. By the same token, optimum Filling Factor has been investigated by exclusively analysing the traditional frequency response of band pass filter from three imperative aspects such as: initial stop band analysis, pass band analysis, and conclusive stop band analysis. In like manner, the parametric comparison has been demonstrated in view of the initial frequency response, selectivity, 3dB cut-off frequency, 3dB pass bandwidth, insertion loss at 2nd harmonics, and the insertion loss at 3rd harmonics to figure out the optimum filling factor for certain planar-EBG patterns.

Sinusoidal appearance of nonuniform dumbbell shape EBGSs in microstrip transmission line

A novel technique of designing nonuniform dumbbell shape electromagnetic bandgap structure (EBGS) assisted microwave transmission line has been proposed that shows distinguished performance. The proposed design has sinusoidal appearance of binomially distributed nonuniform EBG structures. Tapered dumbbell shape EBGS assisted designs using the proposed method have been investigated and the result is compared with the performance of corresponding uniform design. Distinguished low-pass filtering (LPF) performance has been observed from the proposed design that not only shows sharp attenuation; but also significantly low ripples. The basis of the performance has been demonstrated and verified. The proposed technique, moreover, has significantly overcome the limitation of getting increased number of effective tapered EBGSs from the conventional method (i.e. binomial distribution) of tapering.

Dumbbell shape EBG structure — Worth to EBG assisted microwave filter designing

Novel designs of dumbbell shape EBGS have been reported with distinguished filtering features that include larger stopband, dual-band, multi-band and low-pass performance. None but dumbbell shape EBG structure alone can show all mentioned different performances with minor modification and change in dimensions. Beyond the conventional ideas a special idea has been incorporated by restructuring the size and dimension of EBG pattern to amend the result. Proposed designs showed excellent performances that obtained for much smaller etched area; hence ripple heights that mostly depend on etching area get reduced greatly.

Realization of low-pass filters from arbitrarily designed nonuniform EBG structures

Two patterns of electromagnetic bandgap structure (EBGS) have been proposed - one is dumbbell shape EBGS having circular slots as bigger slots and another one is rectangular EBGS. A sequence of arbitrary coefficients has been proposed to make nonuniform EBGSs that results better performance than that of nonuniform EBGSs realized by binomiall coefficients. A potential technique has also been imposed upon the nonuniform dumbbell shape EBG structure that provides more improved scattering parameter performance. An arbitrary nonuniform rectangular patterned EBGS has been investigated too that perform as a low-pass filter. The performances of both proposed designs have been compared to the relevant uniform and binomially distributed nonuniform EBG assisted designs. The results, of arbitrary nonuniform designs, are superior to the conventional form of noninform EBG elements.

Design of the novel defected ground structure assisted microstrip low pass filter

A microstrip transmission line on the Chebyshev distributed defected ground structures (DGSs) and hybrid DGSs realized by interleaving conventional photonic bandgap structures (PBGSs) are proposed. Two different designs are proposed to realize the better performance of the low pass filter (LPF). It is observed that transmission line over non-uniform DGSs have sharper cutoff frequencies and very low ripple passband. These DGSs assisted lowpass filters have achieved the wider stopband. It can be seen that, dumbbell shaped DGS located in the ground plane of a standard transmission line yields LPF with improved performance.

Development of phased array antenna by controlling the filling factor of periodic structure: Research Articles

The new generation of System-on-Chip (SoC) incorporates digital, analogue, RF/microwave and mixed-signal components. Such circuits impose to reconsider the traditional design methods. Mixed-signal designers need novel design methodologies which will have to include accurate behavioral libraries of devices and processes into hierarchical design flows. Thus, this paper describes a behavioral modeling approach which generates neuro-fuzzy-based models for RF/microwave devices. The models, so obtained, can be easily integrated into a VHDL-AMS simulator. This modeling approach is applied to a microwave tunable phase shifter and it is illustrated by the development of a VHDL-AMS model library for RF/microwave applications.