Phased Arrays in Radar and Communication Systems. Pattern Characteristics and Synthesis of Linear and Planar Arrays. Patterns of Nonplanar Arrays. Elements, Transmission Lines, and Feed Architectures for Phased Arrays. Summary of Element Pattern and Mutual Impedance Effects. Array Error Effects. Special Array Feeds for Limited Field of View and Wideband Arrays.

Phased Array Antenna Handbook

The authors present a new approach for localizing electromagnetic sources using sensors where the output of each is a vector consisting of the complete six electric and magnetic field components. Two types of source transmissions are considered: (1) single signal transmission (SST), and (2) dual signal transmission (DST). The model is given in terms of several parameters, including the wave direction of arrival (DOA) and state of polarization. A compact expression is derived for the Cramer-Rao bound (CRB) on the estimation errors of these parameters for the multi-source multi-vector-sensor model. Quality measures including mean-square angular error (MSAE) and covariance of vector angular error (CVAE) are introduced, and their lower bounds are derived. The advantage of using vector sensors is highlighted by explicit evaluation of the MSAE and CVAE bounds for source localization with a single vector sensor. A simple algorithm for estimating the source DOA with this sensor is presented along with its statistical performance analysis. >

Vector-sensor array processing for electromagnetic source localization

In this paper we introduce a new adaptive array beam-former able to work well even when the desired signal and the interference are coherent. The present adaptive beamformers fail to operate in these cases. The results of simulations support the theoretical predictions.

Adaptive beamforming for coherent signals and interference

A simple and flexible genetic algorithm (GA) for pattern synthesis of antenna array with arbitrary geometric configuration is presented. Unlike conventional GA using binary coding and binary crossover, this approach directly represents the array excitation weighting vectors as complex number chromosomes and uses decimal linear crossover without a crossover site. Compared with conventional GAs, this approach has a few advantages: giving a clearer and simpler representation of the problem, simplifying chromosome construction, and totally avoiding binary encoding and decoding so as to simplify software programming and to reduce CPU time. This method also allows us to impose constraints on phases and magnitudes of complex excitation coefficients for preferable implementation in practice using digital phase shifters and digital attenuators. Successful applications show that the approach can be used as a general tool for pattern synthesis of arbitrary arrays.

Sidelobe reduction in array-pattern synthesis using genetic algorithm

The problem of meeting the proliferating demands for mobile telephony within the confinement of the limited radio spectrum allocated to these services is addressed. A multiple-beam adaptive base-station antenna is proposed as a major system component in an attempt to solve this problem. The approach is demonstrated by employing an antenna array capable of resolving the angular distribution of the mobile users as seen at the base-station site, and then using this information to direct beams toward either lone mobiles, or groupings of mobiles, for both transmit and receive modes of operation. The energy associated with each mobile is thus confined within the addressed volume, greatly reducing the amount of cochannel interference experienced from and by neighboring cochannel cells. To ascertain the benefits of such an antenna, the conventional and proposed antenna systems are modeled in a typical mobile radio environment. For a given performance criterion, the theoretical results indicate that a significant increase in the spectral efficiency, or capacity, of the network is obtainable with the proposed antenna. >

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The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems

It is shown how estimation of signal parameters via rotational invariance techniques (ESPRIT) may be used to estimate both the arrival directions and the polarizations of incoming plane waves with a uniform linear array of crossed dipoles. The ESPRIT algorithm exploits the invariance properties of such an array so that both angle and polarization estimates may be computed. Some typical examples showing the use of this method are presented. >

Angle and polarization estimation using ESPRIT with a polarization sensitive array

A numerical technique for pattern synthesis in arrays is presented. For a given set of elements, the technique allows one to find a set of array coefficients that steer the main beam in a given direction and yield sidelobes meeting a specified criterion, if such a set of array coefficients exists. If the pattern specifications cannot be met with the given elements, the algorithm finds the best attainable pattern. The advantage of this technique is that it can be used with an arbitrary set of array elements. Different elements in the array can have different element patterns, and the array can have arbitrary nonuniform spacing between elements. The synthesis technique is based on adaptive array theory. The given array elements are assumed to be used as the elements of an adaptive array. The main beam is pointed in the proper direction by choosing the steering vector for that direction, and the sidelobes are controlled by introducing a large number of interfering signals at many angles throughout the sidelobe region. The algorithm iterates on the interference powers until a suitable pattern is obtained. >

A numerical pattern synthesis algorithm for arrays

It is shown how the ESPRIT (estimation of signal parameters via rotational invariance techniques) algorithm may be used with a square array of crossed dipoles to estimate both the two-dimensional arrival angles and the polarization of incoming narrowband signals. The ESPRIT algorithm exploits the invariance properties of such an array so that both angle and polarization estimates may be computed. Some typical examples showing the use of this approach are presented. >

Two-dimensional angle and polarization estimation using the ESPRIT algorithm

A simple numerical technique for synthesizing array patterns with low sidelobes is described. Unlike classical approaches to this problem, such as the Dolph-Chebyshev method, the technique described is not limited to uniformly spaced linear arrays of isotropic elements. It can be used with an arbitrary collection of elements. The underlying approach is to assume that the given array elements are used as elements of an adaptive array. The main beam is steered in the desired direction by choosing the steering vector for that direction. To reduce sidelobes, a large number of interfering signals is assumed to be incident on the array from the sidelobe region. The power of this method is that it can handle design problems not treatable by any analytical method. This is illustrated for a 33-element linear array of nonuniformly spaced dipoles of varying length, with the axis of each dipole oriented in a different direction. >

It is shown how the ESPRIT algorithm may be used to estimate two-dimensional signal directions and polarizations with a polarization-sensitive array. The ESPRIT algorithm is a signal subspace method, which achieves computational efficiency by exploiting the spatial invariance properties of the crossed dipole array. With the ESPRIT algorithm, two-dimensional direction and polarization estimates are computed directly. The ESPRIT algorithm does not require a search over a multidimensional parameter space, as the MUSIC algorithm does. >

R.T. Compton

Papers

Angle and polarization estimation using ESPRIT with a polarization sensitive array

A numerical pattern synthesis algorithm for arrays

Two-dimensional angle and polarization estimation using the ESPRIT algorithm

A numerical pattern synthesis algorithm for arrays

Two dimensional angle and polarization estimation using the ESPRIT algorithm