Active Element Pattern Method Research Articles

Application of KNN for Linear Array Pattern Prediction Based on the Active Element Pattern Method

In this paper, a machine learning-based algorithm, K-Nearest Neighbor (KNN), is employed to predict the actual patterns of the linear arrays with arbitrary positions and varied element numbers. Based on the assumption that the active element pattern (AEP) is only susceptible to adjacent elements, the AEP of each element is predicted according to its subarray geometry features. And the array pattern is calculated correspondingly. To verify the validity of the method, the proposed methodology was employed to predict the patterns in several array synthesis cases using a dataset constructed from a series of full-wave simulated 17-element microstrip antenna arrays. Numerical results demonstrate that the proposed method is capable of predicting the pattern of arrays with arbitrary geometries and varied element numbers ranging from 7 to 127 with promising precision, which indicates that the proposed method is a feasible and effective array pattern calculation approach and applicable for all linear array synthesis problems with position optimization ability and mutual coupling effect considered.

Improved Prediction of the Wideband Beam Pattern Shape of Antenna Array Based on Infinitesimal Dipole Modeling

An improved prediction of the wideband beam patterns of an antenna array is proposed based on the active element pattern method and infinitesimal dipole (ID) modeling. In the conventional method, the gain of an antenna array can be easily analyzed. However, the prediction of the shape of the beam pattern is limited due to the usage of the slow-varying assumption and the scaling factor. On the contrary, the proposed method uses the free-space dyadic Green's function, which varies for frequencies and all ID elements. By eliminating the slow-varying assumption and the scaling factor, the proposed method, predicting the shape of the beam pattern of an antenna array, is more accurate than the conventional method. The proposed method was verified by the wideband beam synthesis problem for a seven-patch antenna array.

Beam Steering using the Active Element Pattern of Antenna Array

An antenna array is a set of a combination of two or more antennas in order to achieve improved performance over a single antenna. This paper investigates the beam steering technique using the active element pattern of dipole antenna array. The radiation pattern of the array can be obtain by using the active element pattern method multiplies with the array factor. The active element pattern is crucial as the mutual coupling effect is considered, and it will lead to an accurate radiation pattern, especially in determining direction of arrival (DoA) of a signal. A conventional method such as the pattern multiplication method ignores the coupling effect which is essential especially for closely spaced antenna arrays. The comparison between both techniques has been performed for better performance. It is observed that the active element pattern influenced the radiation pattern of antenna arrays, especially at the side lobe level. Then, the beam of the 3x3 dipole antenna array has been steered to an angle of 60° using three techniques; Uniform, Chebyshev and Binomial distribution. All of these are accomplished using CST and Matlab software.

A Simple Measurement Technique for Accurate Bistatic Retrodirective Radiation Pattern Calculation Based on the Active Element Pattern Method

This communication presents a new method for calculating bistatic responses from retrodirective arrays when only monostatic measurement data are available. The proposed approach offers considerable simplification to the measurement facilities required for retrodirective array characterization, since bistatic measurements are significantly more complicated to perform in comparison with monostatic measurements. The method involves making some minor changes to the monostatic measurement configuration, enabling the capture of active element patterns with magnitude and phase data, and combining these with a new expression to obtain the bistatic calculation. Very close agreement has been obtained when compared to actual measured bistatic responses of a ten element retrodirective patch array. In particular, the predicted beam position from the new method is within 0.25° at 40° scan angle, compared to a disagreement of 1.5° using previously reported methods.

Beam Pattern Analysis of Antenna Array on Complex Platform Using AEP Method Based on Hybrid UTD-ACGF Technique

For accurate beam analysis of a radiating antenna array on a complex platform, the mutual coupling and platform scattering effects are important. We proposed a beam pattern analysis method for an antenna array on a complex platform, which combines the active element pattern method of the receiving mode and hybrid geometrical theory of diffraction antenna current Green’s function technique. This proposed method clearly and mathematically divides the beam pattern of the antenna array on a complex platform into mutual coupling and platform scattering components. For a 12 linear dipole array embedded in a complex aircraft, analyses of the beam pattern and boresight error using the proposed method were verified with the method of moment results, which were simulated with FEKO. With reasonably good accuracy, the proposed method can efficiently analyze a beam pattern reflecting the mutual coupling effect and the platform scattering effect. Additionally, convex optimization with the proposed method is simply applied to synthesize the compensated beam pattern.

Design and Analysis of a Silicon-Based Pattern Reconfigurable Antenna Employing an Active Element Pattern Method

In this paper, a silicon-based radio frequency micro-electromechanical systems (RF MEMS) pattern reconfigurable antenna for a Ka-band application was designed, analyzed, fabricated, and measured. The proposed antenna can steer the beam among three radiating patterns (with main lobe directions of −20°, 0°, and +20° approximately) at 35 GHz by switching RF MEMS operating modes. The antenna has a low profile with a small size of 3.7 mm × 4.4 mm × 0.4 mm, and consists of one driven patch, four parasitic patches, two assistant patches, and two RF MEMS switches. The active element pattern method integrated with signal flow diagram was employed to analyze the performances of the proposed antenna. Comparing the measured results with analytical and simulated ones, good agreements are obtained.

Radiation Pattern of Large Planar Arrays Using Four Small Subarrays

The active element pattern (AEP) method is usually employed to efficiently predict the radiation from large arrays when the direct analysis methods are infeasible. However, the standard AEP method needs to compute and store the AEP of each subarray element, and then the AEPs are used to construct those of the large array. To eliminate this cumbersome process, a simplified AEP method is proposed, which only uses the total radiation field of four small subarrays to construct the radiation pattern of large planar arrays. Theoretical derivation of the proposed method is presented. This method has the same accuracy as the standard AEP method, and it is only effective for broadside and uniform excitation arrays. Example arrays of microstrip patch antennas are analyzed and the calculated patterns agree well with those simulated by HFSS.

Application of a modified AEP method for calculation and synthesis of large-scale arrays

The standard active element pattern (AEP) method is presented to predict the radiation from large-scale arrays, in which the AEPs of large array are approximated by those of a small array. However, this method needs to compute and store each AEP of the small array. To avoid this fussy process, a novel AEP method is derived, which simply formulates the radiation field of the large array with that of two small arrays. Furthermore, using the AEP method to evaluate the fitness function of genetic algorithm, a low sidelobe level linear array of 16 aperture-coupled microstrip antennas is designed by optimisation of the element excitations. Numerical results show that the modified AEP method has the same accuracy as the Ansoft HFSS simulation while saving 71% computational cost compared to the standard AEP method.

Improved Main-Beam Nulling Through Single Switchable Displaced Element for Small Scale Adaptive Array

This paper proposes a novel scheme to improve the signal-to-noise ratio (SNR) response of the main beam nulling for small-scale adaptive arrays. This method effectively promotes the main-beam nulling performance by introducing a displaced element at the end of an adaptive array. It is easy to implement with very low system cost. A detailed analysis of its working mechanism is provided, and the performance is verified with the simulation results. A switching scheme is introduced further to realize consistent performance for all nulling regions, which can attain similar main beam nulling performance as a larger-scale adaptive array. Combining with the active element pattern method, the performance of the proposed scheme involving mutual coupling is examined with a dipole array. It is consistent with the results acquired in isolated condition, which verifies its feasibility in practice.

선형 배열 안테나의 방사패턴 계산을 위한 Mirror Active Element Pattern 방법

We propose the mirror active element pattern (AEP) method for the radiation pattern computation of linear array antennas versus scan angles. The computation time for the radiation pattern of linear array antennas using the mirror AEP method is reduced by almost half compared to that using the AEP method because the number of AEPs of elements obtained by the full-wave simulation necessary for the radiation pattern computation of linear array antennas is reduced by almost half. The difference between the radiation patterns of linear array antennas obtained by the full-wave simulation and mirror AEP method is very small for wide scan angle range when the radiation pattern of an antenna element is symmetric.

FAST SYNTHESIS OF LARGE PLANAR ARRAYS USING ACTIVE ELEMENT PATTERN METHOD AND FINE-GRAINED PARALLEL MICRO-GENETIC ALGORITHM

A radiation pattern synthesis technique for large planar arrays with active element pattern (AEP) method and flne-grained parallel micro-genetic algorithm (FGPMGA) is presented. Based on the AEP method, the mutual coupling between array elements can be taken into account. Analysis problems of large rectangular and triangular grid planar arrays are divided into small linear array problems. And for a multiple concentric circular ring array, we only need to obtain one-sixth of all AEPs. So computational cost is greatly reduced. Large planar arrays with low side lobe level (SLL) can be achieved via optimizing the excitation amplitudes and phases. In order to reduce the global optimization time, the FGPMGA is used. This technique is applied to design 256-element rectangular grid, 200- element triangular grid and 4-circle 60-element concentric circular ring E-shaped patch antenna arrays. The radiation patterns calculated by the AEP method show good agreements with those by using CST Microwave Studio.

A SIMPLE STRATEGY TO TACKLE MUTUAL COUPLING AND PLATFORM EFFECTS IN SURVEILLANCE SYSTEMS

This paper presents an optimal power pattern synthesis procedure able to tackle the mutual coupling and platform efiects even for electrically large arrays. The novelty of the approach is due to its capability to account in the synthesis procedure for two difierent aspects at the same time: the coupling between the array radiating elements and the coupling between these elements and the array platform. The mutual coupling evaluation is based on the active element pattern method, and the active element pattern is numerically computed. The kind of synthesis problems here addressed belongs to the class of convex optimization problems. Therefore, the solution is found by means of very e-cient convex programming tools, without requiring global optimization schemes, thus saving time and costs. The extension of the overall tool to adaptive arrays is also considered.

Application of the Active Element Pattern Method for Calculation of the Scattering Pattern of Large Finite Arrays

This letter extends the concept of the active element pattern method that is used to solve the array radiation problem when scattered fields of large finite arrays are calculated. We name this method the original induced element pattern method (OIEPM). The theoretical derivation of the method is presented. In addition, to overcome the limitation and simplify the operation of the OIEPM, an improved induced element pattern method (IIEPM) is proposed, which transforms the large array calculation problem into two small array problems. Unlike the OIEPM that requires calculation of the induced element pattern (IEP) of all the elements of the subarray, the IIEPM merely needs to calculate the fully scattered field of two small arrays. Meanwhile, the effects of the mutual coupling between elements and the edge diffraction are rigorously taken into account. Compared to other numerical and active (or induced) element pattern methods, the IIEPM can greatly reduce the computational cost and simplify the operational procedure. Examples of microstrip patch antenna arrays are analyzed to assess the accuracy and generality of the IIEPM. Numerical examples show that the scattering patterns calculated by the IIEPM and those simulated by the HFSS are in good agreement.

Prediction of Noise and Interference Cancellation With a Moving Compact Receiver Array in an Indoor Environment

An interference and noise cancellation technique based on a reference signal is studied for a compact receiver antenna array placed in an indoor environment. The exact active element pattern method is used to model the radiation characteristics of the array, including mutual coupling between the antenna elements. A two-dimensional ray-tracing technique describes the signal propagation in the indoor environment for a moving receiving antenna.

Beamforming strategies for compact arrays in mobile terminals using the exact active element pattern method

AbstractSome beamforming strategies are presented for compact arrays in wireless systems. To rigorously account for mutual coupling, we rely on the exact active element pattern method. By considering a compact and low‐cost array operating in the HiperLAN band, it is shown that the proposed method allows null steering and beam steering. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 201–203, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10557

Array antenna pattern modeling methods that include mutual coupling effects

Results from an investigation into methods of modeling the radiation patterns of phased arrays that include the effects of radiative mutual coupling are presented. The approaches are based on either the principle of pattern multiplication or the use of active element patterns. Theoretical derivations of the various active element pattern methods are presented. A new method, the hybrid active element pattern method, is introduced. It accurately predicts the patterns of small and medium-size arrays of equally spaced elements. Example arrays of center-fed dipoles are analyzed to verify and illustrate the representations. The results are general and can be applied to arrays of any type of element. The array patterns computed using both the classical pattern multiplication approach and the methods based on active element patterns are compared to those computed using accurate numerical codes based on the method of moments.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>