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New configurations of 2-D phased arrays are proposed in this paper for reducing the number of phase shifters. This design methodology is based on the use of a novel coherently radiating periodic structures (CORPSs) block for 2-D phased arrays. Two new antenna systems for 2-D phased arrays are studied and analyzed utilizing the CORPSs blocks of four inputs and nine outputs. These CORPSs feeding blocks are applied in a smart way to feed the planar antenna arrays by generating the required phase plane and reducing the number of control ports. Interesting results are provided based on the experimental measurements and full-wave simulations. These results illustrate a great reduction of the active devices (phase shifters), providing a good design compromise in terms of the scanning range and side lobe level performance. Furthermore, the provided results illustrate a maximum reduction capability in the number of phase shifters of 81%, considering a scanning range of ±30° in azimuth and ±30° in elevation. A raised cosine distribution is applied to reach side lobe levels of −19 dB for ±18° and −17 dB for ±30° in elevation. These benefits could be of interest to designers of phased antenna systems. [ABSTRACT FROM AUTHOR]

This paper proposes the design of virtual antenna arrays with frequency diversity for radar systems in fifth-generation flying ad hoc networks. These virtual arrays permit us to detect targets from the sky with flying drones. Each array element is composed of a microstrip antenna mounted on quadcopter drones and is virtually connected with the other elements. The antennas are tuned to work at the lower fifth-generation frequency band of 3.5 GHz. The design process considers the optimization of frequency offsets and positions for each element to obtain a side lobe level reduction. This methodology is carried out by particle swarm optimization. Several design examples are presented with random frequency offsets and non-uniform positions. These designs are compared to uniform-spaced arrays excited with Hamming frequency offsets. The simulation results show that using random frequency offsets and non-uniform positions provides a minor side lobe level reduction. This research demonstrates the feasibility of using virtual arrays for radar systems in fifth-generation flying ad hoc networks. [ABSTRACT FROM AUTHOR]

This study presents an analysis of the convex optimization applied to the synthesis of the radiation pattern for linear antenna arrays. This study emphasizes the application of the convex optimization for the array pattern synthesis considering the simultaneous elimination of several zones interferences, reduction of the level of power in two space zones densely populated by interferences, as well as the variation of these zones in terms of proximity-distance of the source of interest, variation of the size of the interferences zones and the number of zones within the radiation pattern. Simulation results are provided. These results define certain levels where the linear array could be exploited to achieve a maximum performance. Key words: Convex optimization, antenna arrays, radiation pattern synthesis, mobile communications, INTRODUCTION Mobile communications systems are facing an increasing demand for heterogeneous broadband services and applications. Given the limited spectrum available to provide high data rate communication for an increasing number [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.compeleceng.2006.01.007 Byline: Aldo Mendez (a), Marco Panduro (a), David Covarrubias (b), Rene Dominguez (a), Gerardo Romero (a) Keywords: Power control; CDMA; QoS; GPS; Admission control; Scheduling; Multimedia traffic Abstract: There is a growing interest in scheduling schemes with QoS (Quality of Service) guarantees for multimedia traffic in mobile cellular networks based on CDMA (Code Division Multiple Access). In this paper, scheduling scheme that provides flexibility in bandwidth allocation and QoS is proposed. In addition, admission control guarantees the E.sub.b/N.sub.o for multimedia traffic considering a perfect-power control (PPC) and closed-power control (CPC). The scheme employs the GPS (Generalized Processor Sharing) service discipline to allocate resources. When comparing the proposed scheme to the existing CDMA-GPS, the results show an improvement in system performance in terms of dropped packets, delay and increased operational throughputs. Author Affiliation: (a) Autonomous University of Tamaulipas, Reynosa-Rodhe Multidisciplinary Academic Center, Carretera Reynosa-San Fernando, Reynosa, Tamaulipas, 88779 Mexico (b) Wireless Communications Group, CICESE Research Center, Km. 107 Carretera Tijuana-Ensenada, Ensenada, Baja California, 22860 Mexico