scholarly journals Numerical studies of bandwidth of parallel-plate cut-off realised by a bed of nails, corrugations and mushroom-type electromagnetic bandgap for use in gap waveguides

2011 ◽  
Vol 5 (3) ◽  
pp. 282 ◽  
Author(s):  
E. Rajo-Iglesias ◽  
P.-S. Kildal
Keyword(s):  
Parallel Plate ◽  
Electromagnetic Bandgap ◽  
Numerical Studies

On the Low Rayleigh Number Asymptote for Natural Convection Through an Isothermal, Parallel-Plate Channel

1991 ◽  
Vol 113 (4) ◽  
pp. 899-905 ◽  
Author(s):  
L. Martin ◽  
G. D. Raithby ◽  
M. M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Asymptotic Behavior ◽  
Nusselt Number ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Boundary Conditions ◽  
Parallel Plate ◽  
Parallel Plates ◽  
Numerical Studies ◽  
Plate Channel

The problem of natural convection through a channel formed by isothermal, parallel plates forms a cornerstone of our understanding of a class of natural convection flows. Following the pioneering study of Elenbaas, it is widely accepted that there is a fully developed re´gime, at low Rayleigh number, in which the Nusselt number becomes directly proportional to the Rayleigh number. This paper gives a detailed analysis of heat transfer in this re´gime. It is concluded that the previous numerical studies, which appeared to confirm this asymptote, used inappropriate boundary conditions, and that the asymptotic behavior should, in fact, not be expected except under very special conditions.

scholarly journals A Dual-Perforation Electromagnetic Bandgap Structure for Parallel-Plate Noise Suppression in Thin and Low-Cost Printed Circuit Boards

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 719
Author(s):  
Myunghoi Kim
Keyword(s):  
Cell Size ◽  
Parallel Plate ◽  
Printed Circuit Boards ◽  
Noise Suppression ◽  
Low Cost ◽  
Unit Cell ◽  
Circuit Boards ◽  
Electromagnetic Bandgap ◽  
Unit Cell Size ◽  
Full Wave

In this study, we propose and analyze a dual-perforation (DP) technique to improve an electromagnetic bandgap (EBG) structure in thin and low-cost printed circuit boards (PCBs). The proposed DP–EBG structure includes a power plane with a square aperture and a patch with an L-shape slot that overcomes efficiently the problems resulting from the low-inductance and the characteristic impedance of the EBG structure developed for parallel-plate noise suppression in thin PCBs. The effects of the proposed dual-perforation technique on the stopband characteristics and unit cell size are analyzed using an analytical dispersion method and full-wave simulations. The closed-form expressions for the main design parameters of the proposed DP–EBG structure are extracted as a design guide. It is verified based on full-wave simulations and measurements that the DP technique is a cost-effective method that can be used to achieve a size reduction and a stopband extension of the EBG structure in thin PCBs. For the same unit cell size and low cut-off frequency, the DP–EBG structure increases the stopband bandwidth by up to 473% compared to an inductance-enhanced EBG structure. In addition, the unit cell size is substantially reduced by up to 94.2% compared to the metallo–dielectric EBG structure. The proposed DP–EBG technique achieves the wideband suppression of parallel plate noise and miniaturization of the EBG structure in thin and low-cost PCBs.

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