Wireless communication systems with reconfigurability capabilities that can dynamically adapt themselves to constantly changing environmental propagation characteristics will be key for the next generation communication scenarios. A communication system capable of changing its output dynamically through reconfigurability features allows maintaining optimal system level performances at all times...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Afroza Khatun Name of the doctoral dissertation Spherical wave theory applied to mobile radio channel modeling, synthesis and emulation Publisher School of Electrical Engineering Unit Department of Radio Science and Engineering Series Aalto University publication series DOCTORAL DISSERTATIONS 205/2014 Field of research Radio E...

Since the release by the Federal Communications Commission (FCC) of a bandwidth of 7.5GHz (from 3.1GHz to 10.6GHz) for ultra wideband (UWB) wireless communications, UWB is rapidly advancing as a high data rate wireless communication technology. As is the case in conventional wireless communication systems, an antenna also plays a very crucial role in UWB systems. However, there are more challen...

in this paper, a novel directional super wide band micro strip antenna based on a simple and new geometry has been proposed. the antenna exhibits the widest bandwidth ever reported to the authors’ knowledge from 50 ghz to 200 ghz. its radiation pattern is approximately steady in the frequency ranges of 50 ghz to 200 ghz. the antenna consists of a club-like radiating patch, a combination of thre...

The problems to be solved by modern radio electronic systems become more and more complicated and diversified. This process is accompanied by the growing of different demands for such systems’ characteristics and, respectively, active searching of considerable improvement of these characteristics. There the importance of the accidental factors (errors) of amplitude-phase distribution (APD) of a...

The authors correct a mathematical equation contained in the correspondence “Multiple-antenna signal constellations for fading channels,” previously published in the IEEE TRANSACTIONS ON INFORMATION THEORY.

This paper proposes a method for determining the optimum antenna weights needed to improve the radiation efficiency in the distributed-feed method for mobile handsets. A test signal from a random wave source embedded in a phantom is employed to optimize the weights. In order to eliminate the affects of polarized waves, the test signal source employs a tri-axial antenna and a random function. We...

In this paper we demonstrate a new and original way to apply the representation theory of finite groups to the development of space-time codes for use in multiple antenna wireless communications. We include a summary of the relevant mathematical model for wireless communications on a multiple-antenna environment. We apply our construction with two examples and demonstrate that they outperform o...

Abstracr We construct simal constellations for differential transmission with multiple basestation antennas. The signals are derived using the theory of fixed-point-free groups and are especially suitable for mobile cellular applications because they do not require the handset to have more than one antenna or to know the time-varying propagation environment. Yet we achieve full transmitter dive...

This paper discusses how to design a Radial Line Slot Antenna (RLSA) whose waveguide is filled with high loss dielectric materials. We introduce a new design for the aperture slot coupling synthesis to restrain the dielectric losses and improve the antenna gain. Based on a newly defined slot coupling, a number of RLSAs with different sizes and loss factors are analyzed and their performances ar...