Constantine A. Balanis

Modern Antenna Handbook

Find the most up-to-date and comprehensive treatment of classical and modern antennas and their related technologies in Modern Antenna Handbook. Have access to current theories and practices in the field of antennas, with topics like metamaterials, microelectromechanical systems (MEMS), frequency selective surfaces (FSS), radar cross sections (RCS), and advanced numerical and computational methods targeted primarily for the analysis and design of antennas. Written by leading international experts, this book will help you understand recent developments in antenna-related technology and the future direction of this fast-paced field.

Smart-antenna systems for mobile communication networks. Part 1. Overview and antenna design

This paper focuses on the interaction and integration of several critical components of a mobile communication network using smart-antenna systems. This wireless network is composed of communicating nodes that are mobile, and its topology is continuously changing. One of the central motivations for this work comes from the observed dependence of the overall network throughput on the design of the adaptive antenna system and its underlying signal processing algorithms. Part 1 of this two-part paper gives a brief overview of smart-antenna systems, including the different types of smart-antenna systems, and the reason for their having gained popularity. Moreover, details of typical antenna array designs suitable for the wireless communication devices are included in this part.

Smart antenna system analysis, integration and performance for mobile ad-hoc networks (MANETs)

This paper focuses on the interaction and integration of several critical components of a mobile ad-hoc network (MANET) using smart antenna systems. A MANET is a wireless network where the communicating nodes are mobile and the network topology is continuously changing. One of the central motivations for this work comes from the observed dependence of the overall network throughput on the design of the adaptive antenna system and its underlying signal processing algorithms. In fact, a major objective of this work is to study and document the overall efficiency of the network in terms of the antenna pattern and the length of the training sequence used by the beamforming algorithms. This study also considers in sufficient detail problems dealing with the choice of direction of arrival algorithm and the performance of the adaptive beamformer in the presence of antenna coupling effects. Furthermore, the paper presents strategies and algorithms to combat the effects of fading channels on the overall system.

Antenna theory: a review

In this review the author traces the history of antennas and some of the most basic radiating elements, demonstrates the fundamental principles of antenna radiation, reviews Maxwells equations and electromagnetic boundary conditions, and outlines basic procedures and equations of radiation. Modeling of antenna source excitation is illustrated, and antenna parameters and figures-of-merit are reviewed. Theorems, arraying principles, and advanced asymptotic methods for antenna analysis and design are summarized. >

Backscatter analysis of dihedral corner reflectors using physical optics and the physical theory of diffraction

Physical optics (PO) and the physical theory of diffraction (PTD) are used to determine the backscatter cross sections of dihedral corner reflectors in the azimuthal plane for the vertical and horizontal polarizations. The analysis incorporates single, double, and triple reflections; single diffractions; and reflection-diffractions. Two techniques for analyzing these backscatter mechanisms are contrasted. In the first method, geometrical optics (GO) is used in place of physical optics at initial reflections to maintain the planar nature of the reflected wave and subsequently reduce the complexity of the analysis. The objective is to avoid any surface integrations which cannot be performed in closed form. This technique is popular because it is inherently simple and is readily amenable to computer solutions. In the second method, physical optics is used at nearly every reflection to maximize the accuracy of the PTD solution at the expense of a rapid increase in complexity. In this technique, many of the integrations cannot be easily performed, and numerical techniques must be utilized. However, this technique can yield significant improvements in accuracy. In this paper, the induced surface current densities and the resulting cross section patterns are illustrated for these two methods. Experimental measurements confirm the accuracy of the analytical calculations for dihedral corner reflectors with right, acute, and obtuse interior angles.

Smart-antenna system for mobile communication networks .Part 2. Beamforming and network throughput

Part 1 of this paper provided an overview of smart-antenna systems, and presented a planar array as a design example. In addition, Part 1 discussed the potential of smart antennas with regard to providing increased capacity in wireless communication networks. Part 2 introduces the signal-processing aspects of the antenna array. In particular, it describes the utility of direction-of-arrival algorithms in array-antenna systems, and gives an overview of the signal-processing algorithms that are used to adapt the antenna radiation pattern. The adaptive-algorithm descriptions are accompanied by simulation results obtained for a specific network topology. In particular, the antenna system is simulated assuming a mobile network topology that is continuously changing. Basic results presented are the dependence of the overall network throughput on the design of the adaptive-antenna system, and on the properties of the adaptive-beamforming algorithms and associated antenna patterns.

Uniform circular and rectangular arrays for adaptive beamforming applications

Numerous studies for smart antennas have already been conducted. However, these studies include mostly uniform linear arrays (ULAs) and uniform rectangular arrays (URAs) and not as much effort has been devoted to other configurations. In this letter, the performance of smart antennas with uniform circular arrays (UCAs) is examined. The primary motivation for this selection is the symmetry UCAs possess. This property provides UCAs a major advantage, the ability to scan a beam azimuthally through 360/spl deg/ with little change in either the beamwidth or the sidelobe level. Also, a comparison between UCAs and URAs in the context of adaptive beamforming is made in this letter.

Higher-order finite-difference schemes for electromagnetic radiation, scattering, and penetration .2. Applications

For pt.1 see ibid., vol.44, no.1, p.134-42 (2002). Higher-order schemes for the finite-difference time-domain (FDTD) method - in particular, a second-order-in-time, fourth-order-in-space method, FDTD(2,4) - are applied to a number of problems. The problems include array analysis, cavity resonances, antenna coupling, and shielding effectiveness case studies. The latter includes a simplified model of a commercial airliner, with a personal electronic device operating in the vicinity of the aircraft. The FDTD computations are also compared to measured data for this case. Incorporating PEC and other types of material boundaries into higher-order FDTD is problematic; a hybrid approach using the standard FDTD method in the proximity of the boundary is proposed, and shown to perform well.

Finite-difference time-domain method for antenna radiation

The finite-difference time-domain (FDTD) method is used to model and predict the radiation patterns of wire and aperture antennas of three basic configurations. A critical step in each is the modeling of the feed. Alternate suggestions are made and some are implemented. The first antenna is a quarter-wavelength monopole and the second is a waveguide aperture antenna. In both bases the antenna is mounted on ground planes, either perfectly conducting or of composite material. The results obtained using the FDTD technique are compared with results obtained using the geometrical theory of diffraction (GTD) and measurements. The third configuration of interest is a pyramidal horn antenna. To model the flared parts of the horn, a staircase approximation was applied to the antenna surface. The computed radiation patterns compared well with measurements. >

Pulse distortion on multilayer coupled microstrip lines

The distortion of pulses due to dispersion and coupling on generalized planar microstrip is investigated. A simple, general form for the Greens function is obtained by solving the boundary value problem separately for the TE and TM modes. The mechanism of even/odd-mode distortion is discussed and numerical results are presented illustrating its effect. The design of structures with low even/odd-mode distortion is considered. Results for pulse distortion on this type of microstrip are also included. >