Dynamic Range Ratio Research Articles

Beampattern Synthesis With Dynamic Range Ratio Constraint via Sequential Convex Optimization

Beampattern Synthesis With Dynamic Range Ratio Constraint via Sequential Convex Optimization

Convex Optimization Algorithm for Maximizing Directivity of Conformal Array With DRR Constraint

The inconsistency of conformal array elements poses a huge challenge to pattern synthesis. Based on convex optimization theory, this paper proposes a novel directivity pattern synthesis method. It can maximize the directivity of dual‐polarized conformal arrays with a low dynamic range ratio (DRR). Firstly, the directivity function is presented under a dual‐polarized conformal array. Then the pattern synthesis based on maximizing directivity is summarized as a multiconstraint optimization problem. In addition, the DRR constraint is introduced to control the weight range. By using Taylor expansion, the problem is transformed into a convex optimization problem and solved iteratively. Finally, simulation results demonstrate that the proposed method can effectively achieve a good directivity pattern with low sidelobe level (SLL) and low DRR.

Multifrequency Phased-Arrays With Dynamic Range Ratio Control for Coastal Monitoring

Multifrequency Phased-Arrays With Dynamic Range Ratio Control for Coastal Monitoring

Synthesis of a Thinned Prephased Electronically Steered Phased Array Using Excitation Control of Both the Small Amplitude Dynamic Range Ratio and Low-Resolution Phase

Synthesis of a Thinned Prephased Electronically Steered Phased Array Using Excitation Control of Both the Small Amplitude Dynamic Range Ratio and Low-Resolution Phase

Synthesis of flat‐top beampatterns based on simple polynomial transforms of Gaussian excitations

AbstractIn the design of antenna arrays which require fast and robust flat‐top beam synthesis, computationally efficient methods are preferred. This feature is usually met by analytical techniques or simple optimisation procedures. On the other hand, in the flat‐top beam synthesis, a common requirement is the ability to control beamwidth or sidelobe level. However, this can result in a high dynamic range ratio (DRR) of array's excitation coefficients. In this paper, a straightforward method for the design of symmetrical flat‐top arrays with controllable sidelobe level or DRR is proposed. The method is based on quadratic and cubic transforms of Gaussian excitations. In addition, the method utilises zero coefficients whose positions are used to control the DRR, including the ability to achieve its minimum. Compared to other flat‐top arrays with analytically shaped beams, the proposed arrays have lower DRRs for the same sidelobe level.

Sum and difference patterns synthesis with common excitation amplitude

This paper focuses on the joint optimization problem of sum and difference patterns with common excitation amplitudes and separate excitation phases. The objective is to reduce the complexity of the antenna system while still maintaining a certain degree-of-freedom (DoF) in synthesizing dual-patterns. The problem is formulated with angular response and common excitation amplitude constraints, making it a nonconvex optimization problem. To address this, we introduce two groups of auxiliary variables to decouple the excitation vector from the complex nonconvex constraints. This allows the original problem to be effectively solved via alternately determining the closed-form solutions for several single-variable optimization subproblems. Additionally, our approach is extended to scenarios involving dynamic range ratio (DRR) reduction, aiming to lower the cost and difficulty of hardware implementation. Theoretical analysis and simulation results are provided to demonstrate that the proposed algorithm can converge to the Karush-Kuhn-Tucker points of the original problem. It is also observed that our approach is capable of generating desired dual-patterns with common excitation amplitudes, regardless of the presence or absence of DRR control.

Pattern synthesis of distorted phased array antenna with unsteady surface deformation considering dynamic range ratio

Abstract This paper presents an optimization method for pattern synthesis of distorted phased array antenna with unsteady surface deformation considering the dynamic range ratio (DRR). In the synthesis approach, different array deformations under unsteady mechanical loads are considered, and the distorted distribution of array elements is calculated after solving the mechanical deformation model. Then, optimize the excitation coefficients of each array element including amplitude and phase with DRR control so as to recover a high-quality pattern from a deteriorated pattern caused by the unsteady deformations. The optimization objective is to minimize the peak sidelobe level, which is synthesized by using a gradient-based algorithm. The optimized excitations can be used as the initial excitation, and the corresponding phase excitations can be derived according to the different deformations.

MMW Signal Gain in DML-Based Microwave Photonic Links Under Large Signal Regime

This paper presents a theoretical and experimental analysis of the millimeter wave (mmW) signal gain observed in photonically generated signals by using carrier suppressed (CS) external modulation in a centralized network architecture while the data is transmitted over a directly modulated laser (DML) operating under different signal regimes. Measurements of the frequency response under small and large signal regimes are presented for the sake of comparison. Moreover, the mmW signal gain has been measured for different standard single mode fiber (SSMF) lengths in order to identify the conditions and impact of large signal regime operation. The results are also validated by the experimental transmission of a 25 MHz QPSK signal transmitted over 40 GHz since the error-vector-magnitude (EVM) is measured for different input electrical power values as well as several received optical power (RoP) levels. Moreover, the spurious-free dynamic range (SFDR) ratio is measured to compare the third-order intermodulation distortion (IMD3) between small and large signal regime. The quantitative results demonstrate that proper system conditions allow the exploitation of the mmW signal gain towards the future deployment of high energy efficient networks.

COSECANT-SQUARED BEAM PATTERN SYNTHESIS OF CONCENTRIC CIRCULAR ANTENNA ARRAY IN A RANGE OF AZIMUTH PLANE USING EVOLUTIONARY ALGORITHM

This paper presents, a pattern synthesis method based on Differential Evolutionary Algorithm. A cosec2 beam pattern has been generated from different concentric circular ring arrays of isotropic elements by finding the optimum set of elements amplitude and phase using the Differential Evolution algorithm. The shaped beam pattern (cosec2) is generated in three predefined azimuth planes (φ=0°, 5° and 10°) from a Concentric Circular Antenna Array (CCAA) having two rings, three rings, and four rings. The total number or isotropic elements are equal for array geometries. The optimum excitation for array geometries is also verified for a range of arbitrarily chosen azimuth planes. The obtained main beam is similar to the desired pattern with some minor variations in peak Side Lobe Level (peak SLL) and ripple. Dynamic range ratio (DRR) is improved by using 4-bit discrete Amplitudes and 5-bit discrete Phases. These discrete excitations also simplify the design complexity of the feed networks.

Deterministic Beamforming for Unmanned Aerial Vehicle Array

This paper addresses the deterministic beamforming for unmanned aerial vehicle (UAV) array (UAVA), which is equipped with an antenna for each UAV. Unlike conventional array, the UAVA can obtain extra degrees-of-freedom for beamforming by flexibly controlling the topology of UAVs, which motivates us to consider an off-grid array layout to improve the beamformer. To effectively control the load of UAVs, we incorporate the dynamic range ratio (DRR) of weighting coefficients of UAVA. On these basis, we formulate a new optimization model aiming to minimize the maximum sidelobe level under the constraints of mainlobe ripple, DRR, layout spacing and array aperture. However, the resulting NP-hard problem is quite challenging due to the exponential form of layout vector and the non-convexity of mainlobe ripple and DRR. In this respect, we reformulate this multi-constrained problem into a new iteration form of combining alternating direction penalty method and majorization-minimization via introducing a series of auxiliary variables. In each iteration, the tractable and small-sized subproblems can almost globally be solved. Numerical results confirm that our method is more suitable for deterministic beamforming of UAVA than the state-of-the-art methods.

ЗАВИСИМОСТЬ СПЕКТРАЛЬНЫХ ХАРАКТЕРИСТИК СИГМА-ДЕЛЬТА АНАЛОГО-ЦИФРОВЫХ ПРЕОБРАЗОВАТЕЛЕЙ ОТ ПОГЛОЩЕННОЙ ДОЗЫ ИОНИЗИРУЮЩЕГО ИЗЛУЧЕНИЯ

This paper presents the results of the study of sigma-delta analog-to-digital converters` main spectral parameters` dependence on the total ionizing dose (TID). Within the framework of this study the main parameters of analog-to-digital converters (ADC) (dynamic, static and electrical) were controlled. The main dynamic characteristics of sigma-delta ADC are signal-to-noise ratio (SNR), spurious-free dynamic range (SFDR), signal-to-noise and distortion ratio (SINAD) and total harmonic distortion (THD). Those have been determined from the spectrum of digitized sine signal using the fast Fourier transform (FFT). Static parameters (integrated nonlinearity (INL), offset and gain errors) were determined using a straight line that linearizes the transfer function, according to the method which is described in the IEEE Standard for Terminology and Test Methods for Analog-to-Digital Converters. National Instruments modular measuring equipment was used for testing ADC`s parameters. Comparative data on the dose dependence of static and dynamic parameters of two sigma-delta ADC and one sigma-delta modulator are obtained. Based on the results, it was concluded that the most sensitive parameters of sigma-delta ADC to TID are its dynamic parameters. Therefore, when assessing the sigma-delta ADC`s radiation hardness, the spectral characteristics of absorbed dose should be kept under control.

Synthesis of Reconfigurable Multiple Shaped Beams of a Concentric Circular Ring Array Antenna Using Evolutionary Algorithms

The approach described in this paper uses evolutionary algorithms to create multiple-beam patterns for a concentric circular ring array (CCRA) of isotropic antennas using a common set of array excitation amplitudes. The flat top, cosec2, and pencil beam patterns are examples of multiple-beam patterns. All of these designs have an upward angle of θ = 0◦. All the patterns are further created in three azimuth planes (φ = 0◦, 5◦, and 10◦). To create the necessary patterns, non-uniform excitations are used in combination with evenly spaced isotropic components. For the flat top and cosecant-squared patterns, the best combination of common components, amplitude and various phases is applied, whereas the pencil beam pattern is produced using the common amplitude only. Differential evolutionary algorithm (DE), genetic algorithm (GA), and firefly algorithm (FA) are used to generate the best 4-bit discrete magnitudes and 5-bit discrete phases. These discrete excitations aid in lowering the feed network design complexity and the dynamic range ratio (DRR). A variety of randomly selected azimuth planes are used to verify the excitations as well. With small modifications in the desired parameters, the patterns are formed using the same excitation. The results proved both the efficacy of the suggested strategy and the dominance of DE over GA as well as FA.

An Effective Optimization Methods for the Suppression of Edge Effects in Ultrawideband Tightly Coupled Antenna Arrays

An effective optimization method is proposed for the suppression of edge effects in finite ultrawideband tightly coupled antenna arrays (TCAAs). By designing a practical finite TCAAs, the influences of edge effects on active voltage standing wave ratio (VSWR) are analyzed. Meanwhile, both the active VSWR and the array gain pattern are formulated as analytical expressions with respect to amplitude and phase excitations for analyzing the design freedom of edge effects. Aimed at suppressing the edge effects within an ultrawideband operation band, a nonconvex optimization problem is established for the synthesis of tightly coupled dipole arrays (TCDAs), where array gains at considered scanning angles and frequencies satisfying given maximum active VSWR and amplitude dynamic range ratio (DRR) are maximized. The nonconvex problem is transformed into an iterative convex optimization problem by the use of an iterative way, and the amplitude and phase excitations are efficiently solved by the convex optimization algorithm accordingly. By comparing to the traditional uniform amplitude and progressive phase excitation (UAPPE) method, the simulated and measured results of the ultrawideband TCDA show that the proposed method can slightly improve array gains at most frequencies, while the active VSWRs are suppressed to 3 over a 10:1 bandwidth when scanning up to 45°.

Optimum Synthesis of Pencil Beams with Constrained Dynamic Range Ratio

In antenna array design, low dynamic range ratio (DRR) of excitation coefficients is important because it simplifies array’s feeding network and enables better control of mutual coupling. Optimization-based synthesis of pencil beams allows explicit control of DRR. However, incorporating DRR into an optimization problem leads to nonconvex constraints, making its solving challenging. In this paper, a framework for global optimization of linear pencil beams with constrained DRR is presented. By using this framework, the methods for synthesis of pencil beams with minimum sidelobe level and minimum sidelobe power are developed. Both methods utilize convex problems suitable for the synthesis of pencil beams whose coefficients’ signs are known in advance. By incorporating these problems into a branch and bound algorithm, the procedures for global optimizations are formed which systematically search the space of all coefficient signs. The method for minimization of sidelobe power is further analyzed in the context of beam efficiency. It is shown that this method can be utilized in an approximate and at the same time global design of pencil beam arrays with maximum beam efficiency and constrained DRR. Based on this approach, a method for the design of pencil beam arrays with minimum DRR and specified beam efficiency is proposed.

An Excitation-DRR Control Approach for Wide-Beam Power Gain Pattern Synthesis

The paper maximizes the minimum power gain in a wide-beam mainlobe when satisfies both the desired sidelobe level (SLL) and the array excitation dynamic range ratio (DRR). We, firstly, set up the power gain pattern synthesis (PGPS) problem with mianlobe/sidelobe constraints and DRR constraint. With the aid of two introduced auxiliary variables, the non-convex mainlobe/sidelobe constraints are converted into linear forms. Then, these two linear constraints are written into the cost function to construct an augmented Lagrangian function of the primal optimization problem. A penalty dual decomposition based approach, which iteratively solves the primal variables in the inner loop and the dual variables in the outer loop, is proposed. The proposed algorithm estimates the power-gain-related variables and the SLL-related variables in a pseudo-analytical way while optimizing the array excitation by solving a constrained least square problem. Both linear array and planar array are simulated to assess the effectiveness and superiority of the proposed algorithm on DRR control issue by comparing it with the existing DRR reduction algorithms. Numerical results show that the proposed algorithm can obtain the highest minimum power gain in the wide-beam when satisfies both the desired SLL and the desired low DRR.

Synthesizing of concentric circular antenna arrays by using a combination of ant lion optimizer and sequential quadratic programming

AbstractAntenna array synthesis is quite a popular topic in electromagnetics and finding suitable array parameter values is a challenging nonlinear engineering problem in this field. In recent years, it has been realized that optimization algorithms can be used to achieve desired solutions in this area. Besides, improvements in the optimization algorithms make it possible to perform synthesis processes on different array structures and to obtain better results. In this paper, a method based on a combination of ant lion optimizer (ALO) and sequential quadratic programming (SQP) is proposed for the concentric circular antenna array (CCAA) synthesis. Excitation amplitudes of array elements are optimized for CCAAs with low maximum sidelobe level (MSL), narrow first null beamwidth (FNBW), and low dynamic range ratio (DRR). The results of proposed ALO‐SQP method are compared with those of 11 different algorithms: ALO, moth flame optimizer (MFO), SQP, symbiotic organisms search (SOS), biogeography based optimization (BBO), opposition‐based gravitational search algorithm (OGSA), cat swarm optimization (CSO), firefly algorithm (FA), evolutionary programming (EP), backtracking search optimization algorithm (BSA), and seeker optimization algorithm (SOA). The comparisons indicate that the CCAAs synthesis using the proposed method presents good MSLs, FNBWs, and DRRs.

16.5: Key Technologies and Algorithm of Measurement for Mini‐LED‐backlit LCDs

Mini-LED-backlit LCD display has extremely high dynamic range and contrast ratio, but also brings halo effect. The halo phenomenon will make the original high-definition, high-contrast picture seems to be covered with a veil, which reduces the visibility and quality of the picture, and cannot reflect the superiority of HDR display. Based on the measurement and evaluation requirements of Mini-LED-backlit LCD displays, this paper proposes a test and evaluation scheme for halo phenomenon, and analyzes the key factors affecting the measurement, including the V(λ) mismatch, measurement lower limit and dynamic range, imaging quality of imaging luminance meter and halo evaluation algorithm based on Mura analysis, etc. .

ANUINDRA: A wide dynamic range FEE ASIC for a silicon–tungsten electromagnetic calorimeter

A wide dynamic range (ratio of maximum detectable signal to noise floor) front end electronics (FEE) readout ASIC ANUINDRA has been developed in 0.35μm standard N-well CMOS technology for the prototype forward calorimeter (FOCAL), a silicon–tungsten (Si–W) electromagnetic (EM) calorimeter, proposed as part of the ALICE upgrade at CERN. It is a 16 channel pulse processing ASIC with a multiplexed serial output along with all the individual channel’s responses available as output pins. Each channel consists of a charge sensitive amplifier (CSA), semi-Gaussian pulse shaper, gain-stage, and Track & Hold stage. The ASIC has been designed with a linear operating range of 2.6 pC w.r.t the input charge and a measured charge gain of 1.34 mV/fC. ANUINDRA ASIC shows a noise level (ENC) of 820 e− with 0 pF of detector capacitance. A baseline recovery of better than 1% within 5μs can be attained by adjusting the pole–zero locations with the help of external voltage control. The fabricated and packaged ANUINDRA was successfully tested and characterized in the laboratory and with a high energy particle beam at the SPS beamline in CERN. The design details of ANUINDRA ASIC along with the test results are presented herewith in this paper.

Design optimization of linear arrays and time‐modulated antenna arrays using meta‐heuristics approach

AbstractThis article presents an approach to design a non‐uniformly excited linear array antenna (LAA) and an alternate solution to LAAs in the form of time‐modulated linear arrays (TMLA) for optimum far‐field radiation pattern synthesis. The performance analysis of both the antenna arrays is studied, and the advantages and limitations of the proposed design approaches are presented with numerical outcomes. The far‐field radiation pattern is optimized to reduce the interference by simultaneously lowering the sidelobe levels and increasing the directivities of LAAs and TMLAs. A recently proposed meta‐heuristics computation technique called whale optimization algorithm (WOA) is employed to get the optimal results. The current excitation amplitude and the inter‐element spacing of the 16‐element LAA are optimized with WOA to attain the desired results. However, due to the large dynamic range ratios (DRRs) of excitation weights, array feed network complexities are increased, which restricts the design of typical LAAs. TMLAs can be regarded as an alternative solution where the problem of large DRRs as well as the design complexities of LAAs are eliminated. The concept of ‘time’ is vital in time‐modulation as it plays the role of an added degree of freedom realized by periodically turning ON and OFF the radio‐frequency switches with an electronic control circuit to achieve an enhanced array radiation pattern. WOA is utilized to determine the optimal switch‐ON time periods for each array element and the optimal inter‐element spacing of a 16‐element TMLA. A set of numerical results validates the advantages of TMLAs over LAAs, and the limitations of TMLAs with respect to LAAs are also indicated. The performance of both the arrays is then compared with other published literature results to establish the superiority of the proposed approach.

Low-Sidelobe Shaped-Beam Pattern Synthesis With Amplitude Constraints

The article deals with the low-sidelobe shaped-beam pattern synthesis (SBPS) problem under amplitude constraints, including the controllable dynamic range ratio (DRR) and the predetermined excitation amplitude. The formulated problem is nonconvex owning to the existing nonconvex constraints. To this end, a set of auxiliary variables are introduced to reformulate the original problem, and then a double-loop iterative algorithm based on the penalty dual decomposition method (PDD) framework is proposed. The proposed approach solves the reformulated problem by updating primal variables with block successive upper-bound maximization (BSUM) algorithm in the inner loop and updating the dual variables and penalty parameter with the constraint violation strategy in the outer loop. One important advantage of the proposed approach is that all of its subproblems have closed-form solutions, which guarantees that the reformulated problem can be effectively solved. Numerical simulations are carried out to validate the proposed approach’s superiority with both isotropic element pattern and active element pattern (AEP). The results show that the proposed approach can obtain a lower sidelobe level (SLL) and a smaller DRR when compared with the state-of-the-art approaches.