Wideband Electromagnetic Bandgap Structure Research Articles

Coupling Reduction of Two Adjacent Quad-Ridge Horn Antennas at 20-40 GHz Frequency Range by Using of Wideband Electromagnetic Band Gap Structure

In this paper, the Electromagnetic Band-Gap (EBG) structures have been used to decrease the mutual coupling between two wideband quad-ridge horn antennas. The EBG structure is a small sheet with a length of 6 cm and a width of 10.6 cm, and it was placed vertically between the horn antennas, providing us with a very compact system. Full-wave CST simulations have been carried out to simulate the whole structure. A two-layer EBG structure has provided a 17 dB isolation over the 20-40 GHz frequency range. Moreover, to verify the proposed structure, EBG layers have been fabricated and measured. The S parameter and far-field measurements of the horn antennas were conducted to investigate the isolation and radiation patterns of the antennas. The measurement results were perfectly comparable with the simulations. Moreover, because of the standalone characteristic of the designed EBGs, this structure can be used as an add-on unit to decrease the E-plane mutual coupling of any two antennas.

Multi-stack Technique for a Compact and Wideband EBG Structure in High-Speed Multilayer Printed Circuit Boards

We propose a novel multi-stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high-speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS-EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS-EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port-to-port spacing than the unit-cell length, thus overcoming a limitation of previous EBG structures.

A Compact and Wideband Electromagnetic Bandgap Structure Using a Defected Ground Structure for Power/Ground Noise Suppression in Multilayer Packages and PCBs

In this paper, we propose a compact and wideband electromagnetic bandgap (EBG) structure using a defected ground structure (DGS) to significantly enhance the wideband suppression of power/ground noise coupling in multilayer packages and printed circuit boards. The proposed EBG structure is implemented simply by adding a rectangular-shaped DGS which is etched periodically onto the ground plane without changing any other geometrical parameter from a mushroom-type EBG structure. The DGS effects on the f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</sub> are thoroughly analyzed using the dispersion characteristics. We experimentally verified that the proposed EBG structure achieved the wideband power/ground noise suppression (below -40 dB) between 2.5 and 16.2 GHz. In addition, we demonstrated the considerable reduction in f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> from 3.4 to 2.5 GHz and a significant increase in f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</sub> from 9.1 to 16.2 GHz when compared with the mushroom-type EBG structure.

Efficient EMI reduction in multilayer PCB using novel wideband electromagnetic bandgap structures

Electromagnetic interference is a significant problem in high-speed circuits. To minimize its effect and improve the electrical characteristics of circuits such as signal integrity and electromagnetic compatibility, the application of an electromagnetic isolation structure with electromagnetic bandgap (EBG) is considered. In this paper, a novel wideband EBG structure is proposed for EMI reduction in multilayer printed circuit boards (PCB), in which a kind of improved L-bridge is used as additional series inductance, and the equivalent inductance can be increased significantly. Compared to the traditional mushroom-liked EBG structure with the same parameters, the L-bridge structure can broaden the relative bandwidth to nearly 250%, with a significant decline of the center frequency. The effectiveness and accuracy of this structure are verified by both simulations and measurements. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. © 2011 Wiley Periodicals, Inc.

Novel Compact Wide-Band EBG Structure Based on Tapered 1-D Koch Fractal Patterns

This letter presents a novel electromagnetic band-gap (EBG) structure in microstrip technology based on nonuniform one-dimensional (1-D) Koch fractal patterns whose dimensions and period are modulated by a tapering function that significantly improves the width of the band-gap. This wide band-gap is achieved by maintaining the radius-to-period (r/a) ratio of the Koch fractal patterns larger than 0.5 in the whole structure. In the passband region, an improved flat response is obtained by tapering the dimensions of the Koch fractal patterns etched in the ground plane, together with the width of the microstrip line, with a Kaiser distribution that also modulates the periodicity of the fractals. A major consequence of this modulation of the periodicity of the pattern is that this structure is much more compact than a uniform conventional one.

Enhanced Bandwidth Artificial Magnetic Ground Plane for Low-Profile Antennas

In this letter, it is shown that using magneto-dielectric materials as substrate can increase the in-phase reflection bandwidth of electromagnetic bandgap (EBG) structures. To show this, a compact wideband EBG structure is designed and simulated. The numerical results show that this EBG has an in-phase reflection bandwidth of 70% which is several times greater than a conventional EBG resonating at the same frequency. Additionally, the new EBG surface has a smaller cell size, an important feature in the design of small antennas. As a demonstration of the effectiveness of the new structure, a low-profile unidirectional spiral antenna is designed to operate from 8 to 18 GHz. The improvement in the voltage standing wave ratio (VSWR) and gain of this antenna is presented while comparison is made to the case when using conventional EBG surface.