A Novel ??-Negative Metamaterial with Enhanced Rejection Bandwidth

Published by and copyright of Science Publications. The definitive version of this article is available at: http://thescipub.com/abstract/10.3844/ajeassp.2013.137.144In this study, a novel planar ??-Negative (MNG) metamaterial structure based on Split Ring Resonators\ud (SRRs) with improved rejection bandwidth is presented. A bridging technique is used to connect two SRR\ud unit cells at the center to emulate a cascaded filter. The proposed structure achieved a -20 dB rejection\ud bandwidth of 15.5% compared to 4.5% for the conventional SRRs which makes it a good candidate for\ud integration with antennas and RF circuits that require large operational bandwidth

Decoupled and Descattered Monopole MIMO Antenna Array with Orthogonal Radiation Patterns

This chapter introduces a novel design concept to reduce mutual coupling among closely-spaced antenna elements of a MIMO array. This design concept significantly reduces the complexity of traditional/existing design approaches such as metamaterials, defected ground plane structures, soft electromagnetic surfaces, parasitic elements, matching and decoupling networks using a simple, yet a novel design alternative. The approach is based on a planar single decoupling element, consisting of a rectangular metallic ring resonator printed on one face of an ungrounded substrate. The decoupling structure surrounds a two-element vertical monopole antenna array fed by a coplanar waveguide structure. The design is shown both by simulations and measurements to reduce the mutual coupling by at least 20 dB, maintain the impedance bandwidth over which S11, is less than −10 dB, and reduce the envelope correlation coefficient to below 0.001. The boresight of the far-field radiation patterns of the two vertical monopole wire antennas operating at 2.4 GHz and separated by 8 mm (λo/16), where λo is the free-space wavelength at 2.45 GHz, is shown to be orthogonal and inclined by 45° with respect to the horizontal (azimuthal) plane while maintaining the shape of the isolated single antenna element

Three-Dimensional Microstrip Antennas for Uniform Phase Response or Wide-Angular Coverage GPS Applications

In this chapter, three-dimensional microstrip antennas operating in the dominant TM10 mode of the L1 band at 1.57542 GHz are presented, which either provide uniform phase response and stable phase center, or wide angular beam coverage. A Finite-Difference Time-domain scheme has been developed and used to elucidate the interplay between the proposed antennas and several ground plane configurations. Experimental results are presented and compared to simulations to illustrate the impact of several 3-D geometries on the phase response, phase center, half power beam width, gain, and polarization purity. We report for the first-time novel three-dimensional microstrip antenna topologies for precise surveying applications by fostering a nearly uniform phase response when the 3D structure is bent by angles ranging from 15° to 30° without significantly compromising the gain and polarization performance of the equivalent flat patch antenna. The proposed antennas exhibit half-power-beamwidths up to 40 and 80% greater than the equivalent flat structure that can be realized if positioned downward and upward respectively, for bend angles above 45° accompanied with a variety of spatial coverage patterns to suit applications involving highly dynamic platforms

Stochastic versus Ray Tracing Wireless Channel Modeling for 5G and V2X Applications: Opportunities and Challenges

Due to the rapid development of wireless communication applications, the study of Multiple Input Multiple Output (MIMO) communication systems has gained comprehensive research activities since it can significantly increase the channel capacity and link reliability without sacrificing bandwidth and/or transmitted power levels. Researchers tend to evaluate the performance of their MIMO antenna arrays using various channel modeling tools. These channel models are mainly categorized into either deterministic channels based on Ray Tracing (RT) tools or Stochastic Channel Models (SCM). In this chapter, we compare these two categories in terms of the MIMO channel capacity using a complete description of the antennas at the transmitting and receiving ends in terms of 3D polarimetric radiation patterns and scattering parameters. The performance is evaluated for 5G New Radio (NR) Enhanced Mobile Broadband (eMBB) and Ultra-Reliable Low-Latency Communication (URLLC) services and Vehicle-to-Everything (V2X) systems using state-of-the-art commercial SCM and RT tools to provide information regarding the capabilities and limitations of each approach under different channel environments and the Quality of Experience (QoE) for high data rate and low latency content delivery in the 5G NR sub-6GHz mid-band Frequency Range-1 (FR1) N77/N78 bands

Parity Assisted Decision Making for QAM Modulation

This paper discusses parity assisted decision making for QAM modulation

User-Based Channel Assignment Algorithm in a Load-Balanced IEEE 802.11 WLAN

This article discusses a user-based channel assignment algorithm in a load-balanced IEEE 802.11 WLAN

User-Based Channel Assignment Algorithm in a Load-Balanced IEEE 802.11 WLAN

This article discusses a user-based channel assignment algorithm in a load-balanced IEEE 802.11 WLAN

Channel Assignment and Load Distribution in a Power-Managed Wlan

This paper discusses a proposed algorithm