Array pattern nulling using the elevations of selected elements of phased antenna arrays

Formulation of the problem. Many electronic applications (for example, satellite communications) impose significant restrictions on the weight and dimensions of the antenna devices used. In addition, the antennas used should have the lowest possible cost and simplicity of design. To solve these problems, it is proposed to use a method for reducing the number of antenna elements in phased antenna arrays based on the method of point sources. Purpose. The purpose of this work is to develop a method for reducing the number of antenna elements in phased antenna arrays while maintaining the parameters of their radiation patterns. Results. As a solution, it is proposed to place the antenna elements above the metal sheet at a distance 1.5–2 times smaller than the size of the antenna array itself, which will significantly reduce the number of elements of the latter without deteriorating its radiation pattern during wide-angle two-coordinate scanning of space with the main lobe. Practical significance. Obtained results can be used to create phased antenna arrays with a reduced number of elements, which will reduce the size, weight and cost of the device.

There is a need for compact, broadband, efficient radiators for terahertz integrated circuits, to serve as feed for large-aperture quasioptics, or as antenna elements in phased arrays. We present a condensed, subwavelength progressive transition between a terahertz microscale dielectric waveguide and a dielectric slot radiating aperture. The result is an endfire point-source radiator spanning <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&gt;$</tex-math></inline-formula>2.2:1, from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula>185 GHz to 410 GHz, which is fabricated in a single etch step from a high-resistivity float-zone intrinsic silicon wafer. The radiation phase center deviates by just <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula>500 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\upmu$</tex-math></inline-formula>m across the operation bandwidth—less than one free-space wavelength.

Optical-fiber technology offers many advantages to the communication and radar industries, including high bandwidth and low loss. Single-mode fiber has a bandwidth-distance product greater than that of coaxial transmission lines. Applications of millimeter-wave transmission include processing of hundreds of antenna elements in phased arrays for radar and communication systems, antenna remoting, delay lines, and free-space intersatellite communications. Laser diodes have been used as transmitters at carrier frequencies as high as 16 GHz, and optical fiber has served as an excellent replacement for microwave and waveguide transmission lines.1,2 However, applications to millimeter-wave systems have not been possible because the largest direct modulation bandwidth reported to date in highspeed laser diodes is only 28 GHz.3

In traditional aerospace telemetry receiving systems, parabolic directional antenna or flat array antenna is generally adopted in the ground telemetry receiving antenna. The antenna array is synthesized into a fixed beam, tracking the target by mechanical scanning. When tracking multi-target is required, it is necessary to deploy multiple ground telemetry antennas to track their respective targets, i.e. one set of antennas tracks one target. Phased arrays antenna is an antenna system and technology developed on the basis of array antenna. Its antenna elements are synthesized into multiple independent beams, which can track one target at the same time, or track each target separately with different beams, so as to achieve the multi-target telemetry and tracking receiving function with a set of phased array antenna. The antenna array element is synthesized into multiple independent beams. This paper mainly discusses an implementation method of multi-target telemetry receiving antenna based on phased arrays technology.

In this paper we consider the development of wideband direction finder for VHF/UHF frequency band, taking into account the number of antenna elements in the antenna array, and the number of RF channels in the wideband receivers. Two variants of the wideband direction finder have been considered. In the first case, the number of RF channels is equal to number of antenna elements in the antenna array (parallel data acquisition). In the second case, the number of RF channels is lower than the number of antenna elements in the antenna array (sequential data acquisition). In order to compare these two variants, root mean square error of direction of arrival has been calculated. Some simulation are performed in MATLAB and results are shown in this work.

A deterministic method for detecting faulty elements in phased arrays is proposed and tested against experimental and numerical data.The solution approach assumes as input the amplitude and phase of the near-field distributions and allows to determine both positions and currents of radiating elements.The corresponding non linear inverse problem is properly solved by exploiting the distributional approach, which allows to cast the initial problem to the solution of a linear one, whose solution is made stable by adopting a proper regularization scheme based on the Truncated Singular Value Decomposition tool.The results fully confirm accuracy of the proposed technique.

The aim of this paper is to introduce the preparation of antennas for a jamming system, which will be used for interference communication UAV. There are many types of antennas. In this work design and testing of pyramidal horn antenna will be described. Horn antennas are widely used in areas of wireless communication, also used as high gain elements in phased arrays. In this paper calculations of the parameters of the pyramidal horn and application to optimize the size of the antenna will be presented. All calculations and application to optimize the antenna will be implemented in MatLab. After the numerical modeling and building, the antenna will be tested in an anechoic chamber.

Array pattern synthesis (APS) aims to create the desired array pattern as closely as possible to the prescribed mask template by varying the element excitations of the array. Herein, an efficient approach for the APS to control the sidelobe level is proposed. After designing the mask template to meet the prescribed sidelobe requirements and the waveform pattern, a set of element excitations is calculated through the Fourier transform performed on the projection the waveform pattern onto the mask template. Then, a desired array pattern can be synthesized from this updated set of excitation coefficients. The proposed APS approach directly presents a mathematical formulation of the exact set of excitations without any iterative optimization process. The proposed method is particularly suited for many array elements in linear antenna array. Thus, the proposed APS achieves substantial improvements in terms of computation complexity, performance, and ease of implementation in the algorithm when compared with conventional methods. Several simulation results are provided to verify the efficacy and effectiveness of the proposed method.

Enhancing signal quality, minimizing interference, allowing high-speed data transmission, and beam steering in phased array antennas are pivotal in today's wireless communication systems.In terms of global optimality, low side lobe levels, and fast convergence, conventional optimization methods often fail to deliver.The ease and adaptability of metaheuristic algorithms, such as the Whale Optimization Algorithm (WOA), have rendered them desirable solutions for managing such complex optimization problems.However, traditional WOA may still suffer from premature convergence and failure to exploit the search space fully.This study proposes a Chaos-Enhanced Whale Optimization Algorithm (CWOA) in intelligent beam steering for phased array antennas.A significant enhancement is that the algorithm can now escape local optima more effectively and attain higher global convergence due to the integration of chaos theory into the WOA framework.Chaotic maps such as the logistic and tent maps generate dynamic control parameters that guide the search for a more balanced exploration-exploitation trade-off.To reduce side lobe levels and give accurate main lobe steering, the proposed CWOA is employed to enhance phase excitation of the antenna elements in a uniform linear array (ULA).Beam direction accuracy, side lobe suppression, and convergence speed are three domains where the CWOA performs better in simulations than normal WOA, PSO, and GA.By comparing various approaches, we realize that chaotic integration significantly enhances the performance of WOA in adaptive beamforming and real-time applications.Innovative and self-adaptive beam steering in dynamic environments like 5G, radar, and satellite communications can be built on this research's efficient and resilient optimization framework for next-generation antenna systems.

A phased-array focusing technique is described that results in far-field antenna patterns being formed at distances as close as one array diameter. This will allow experimental verification of adaptive-array far-field performance in an anechoic chamber of reasonable size. This phased-array focusing technique accounts for parallax effects by matching the null locations of the actual far-field pattern with null locations created in the antenna pattern at close range. In this manner, the gain, beamwidth, and sidelobe behavior of the antenna pattern observed in the near field can be matched exactly to the corresponding far-field pattern. The required array excitation function is determined by inversion of the array pattern matrix. The near-field focusing technique was experimentally verified using a 32-element, linear, L-band phased array. The focused antenna patterns were measured directly by a probe on a linear scanner running parallel to and an array diameter away from the ground plane. Very good agreement with theoretical predictions was achieved. >

this study presents an eight array ultrasonic signal phased array sparse sampling experiment system based ultrasonic phased array technology and Compressed Sensing (CS). Proposed system considers recovery ultrasonic beam signal received eight phased array elements with sparse samples captured using sub-Nyquist model in CS recovery algorithm. We have the block defect detection test in the system. The test result approximated the actual block defect position. Based on block defect detection test, We compared sparse sampling value using spectrum estimation to Compressed Sensing recovery algorithm imaging, and no focus and focus detection effect, proved the phased array experiment system based on Compressed Sensing .it can greatly improve the detection signal to noise ratio (SNR) and sensitivity. So we verify the phased array focus can improve the detection ability.

Reducing the mutual coupling of antenna elements in 60-GHz phased arrays is an important issue because it directly affects the port impedance and radiation patterns. This paper presents an EBG-based design using corrugated structures to reduce the mutual coupling between two antenna elements with an edge-to-edge distance of 1.65 mm (0.33λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ). Isolation enhancement using the corrugated structure with a height of 0.65 mm is up to 10.3 dB in simulation and is assured over the frequency of 57 to 66 GHz. Limited to the LTCC process with each layer of 0.1 mm height, the prototype of a corrugation height of 0.7 mm is chosen to verify the isolation enhancement and the agreed experimented and simulated results are shown.

Summary form only given, as follows. A millimeter wave phased antenna array (PAA) has been proposed for use in plasma imaging reflectometric diagnostics and is currently under design and fabrication. To account for the rapid changes of the cutoff layer with plasma density variation, a true time delay (TTD) controlled phased antenna array (PAA) is being developed as an artificial lens with controllable focal length for launching the illumination beam of the microwave imaging reflectometry (MIR) system. The beam shaping concept illustrates that programming the PAA generates concave (focusing/beam narrow) or convex (defocusing/beam broaden) wavefronts by properly arranging the time delay (or phase shift), therefore, the PAA functions like a real optical lens. The focal properties can be easily changed by different time delay arrangement at high speed so that real time control is possible on time scales significantly faster than plasma changes. The operation frequencies for the first implementation of beam shaping antenna array are set as 45-55 GHz based on the NSTX MIR system requirements. The time delay unit utilizes a piezoelectric translator (PET)-driven perturber to vary the propagation velocity along low loss microstrip lines. Tapered slot antenna will be used in the system as array element. To overcome the system loss and scattering loss from the plasma, the beam shaping array system is designed with an output power of at least 50 mW, and with a desired variable 3-dB beam width extending from 15/spl deg/ to 25/spl deg/.

A novel approach for the independent manipulation of the in- band scattering and radiation patterns of phased arrays with high radiation efficiency is proposed. The in- band scattering and radiation mechanism of an array element is analyzed first. It is found that the antenna input impedance may lead to different effects on the antenna scattering and radiation patterns. Taking advantage of this difference, an array element incorporated with a biased p-i-n diode is designed, which has two scattering states with 180° phase differences but a stable radiation state. By controlling the biasing state of the p-i-n diode connected to each element, the scattering pattern of the proposed array can be manipulated dynamically. Meanwhile, the stable radiation pattern of the designed element ensures that the proposed phased array can dynamically radiate a beam scanning to a given direction with high efficiency during the manipulation of scattering patterns. The final designed linear array with p-i-n diodes is able to operate at 2.6–3.4 GHz with a radiation beam scanning up to ±45°. Moreover, the reconfigurable scattering beams of the proposed array can point to arbitrary angles within ±60°, thus the in- band scattering is significantly reduced in a broad bandwidth. To validate this design, a prototype array is fabricated and measured. Measured results are in good agreement with the simulated results.

Traditionally the radiation beams of phased array antennas are formed by linearly shifting the phases of the transmitted waveforms from the antenna array elements, and the antenna beams can be scanned from one direction to another by subsequently changing the waveform phases [1, 2]. Digitally forming receiving antenna beams can be implemented by digitally filtering the received signals at array elements and have been widely used. However, digitally forming virtual transmitting beams or both transmitting and receiving beams has been very technically challenging. Yet there are many potential advantages for employing virtual transmitting beams rather than real phased array antenna beams. For example, in forming virtual transmitting antenna beams, the radiation energy of the antenna is not physically focused in any particular direction and thus is very difficult to be detected. As a result, the virtual radiating system can operate in a dasiasilentpsila mode with an extremely low probability of interception (LPI). Because the virtual radiation beam is formed through digital filtering of the received signals, the formed beams are more accurate and concentrated for intended radiation direction compared with phased array antenna beams. In addition, with virtual radiation systems, multiple transmitting-receiving beams can be generated simultaneously. In this work, we propose an innovative approach to forming virtual digital antenna beams (VDAB) by transmitting and processing orthogonal coding waveforms. The principle and architecture of the proposed system will be introduced and some simulated results will be presented to demonstrate the feasibility of the new systems.