Formation of a threened phased antenna array using the point source method

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.

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.

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/.

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.

In the practical application of aircraft, there may be situations when it is not possible to resolve radar target signals in the measurement channels of range, speed and angular coordinates in the on-board radar system. In these situations, it is advisable to use angular estimation procedures with super-resolution in the onboard radar system. Various methods and algorithms of angular estimation with super-resolution are known, each of which has its own advantages and disadvantages. At the same time, there is no information in the available scientific and technical literature about the algorithms of angular estimation with super-resolution used in the onboard radar system, knowledge of which is necessary when designing promising onboard radar systems. The article systematizes and analyzes the methods and algorithms of angular estimation with super-resolution. The classification of methods of angular estimation with superresolution is given. The generalized information about the known one-dimensional and twodimensional methods and algorithms of angular estimation is given. The algorithms proposed for use in flat antenna arrays, concentric ring antenna arrays, ring antenna arrays, round four-quadrant antenna arrays, flat antenna arrays with a total output signal are considered. It is noted that the features of the construction of radar homing heads include a reduction in the total number of information processing channels achieved by combining antenna elements into sublattices, the output signals of which are used to estimate the angular coordinates of radiation sources. The specificity of such antenna arrays is that the antenna sublattices have radiation patterns that are narrower than those of weakly directed antenna elements. In addition, the distance between the antenna modules can significantly exceed the distance between the antenna elements in a conventional antenna array and at the same time significantly exceed the wavelength size. To determine the possibilities of applying in practice the algorithms of angular two-dimensional estimation with super-resolution considered in the article in the onboard radar system, it is necessary to conduct special studies.

Spherical phased-array antenna has hemispherical scan coverage for transmission of satellite imagery data at high bit rates to the ground station. Different conditions have been assigned based on their effects on the overall performance of the communication link. Reliability analysis consequently becomes an important requirement of any system onboard a satellite. Although the phased array and some connected algorithms have been presented in the literatures; however, there is no extensive systematic and theoretical performance evaluation framework formulated. In this work, the authors present new method that efficiently and effectively analyses the statistical performance of phased-array antenna systems using spherical harmonics expansion approach. Specifically, the errors caused by limited antenna element number, measurement noise of antenna, imprecision in phased-array antenna elements positioning, and spatial aliasing are systematically and theoretically benchmarked via simulations. Spatial sampling mechanisms for the positioning of array antenna elements on a sphere are presented and evaluated. This study proposed design guide and analysis for spherical phased-array antenna systems, and antenna arrays that do not employ spherical harmonics explicitly.

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.

Antenna integration and miniaturisation techniques are crucial for maintaining the desired electrical and physical properties of antennas, while meeting the growing demands for reliable link performance and compact device designs for emerging wireless communications. This Special Issue presents recent advances in the theory, analysis, design, and application of antenna integration and miniaturisation. These techniques are enabling diverse novel designs and applications, propelling advancements in integrated circuits, and next-generation wireless communication systems rapidly. The papers in this Special Issue present the state-of-the-art contributions that address the challenges of design, fabrication, and performance enhancement for miniaturised and integrated antennas. This Special Issue includes six high-quality papers, each presenting unique innovations in the field of antenna integration and miniaturisation. Thus, the overall submissions are of high quality, which marks the success of this Special Issue. Ye et al. present a high-gain circularly polarised magneto-electric dipole antenna array with metallic radiating structures for millimetre-wave applications. This paper proposes a novel design of a magneto-electric dipole antenna array for millimetre-wave applications. The novel use of metallic radiating structures helps achieve high gain and circular polarisation, making the proposed design ideal for millimetre-wave communication systems. Truong et al. introduce a method for designing an electrically small printed square loop antenna for closely spaced transmitter-receiver (Tx/Rx) systems. This paper demonstrates a compact antenna design, featuring a simple series combination of two lumped inductors and two interdigitated capacitors, providing inherent impedance matching without the need of an additional matching network. This proposed compact design method is highly relevant for modern and emerging wireless communication systems where space is often limited and confined. Mao et al. propose a null-depth coordinated synthesis design approach for azimuthal null frequency scanning antennas (ANFSAs). A synthesis chart gauged by different null-depths is developed to determine the respective exciting amplitude and phase conditions for the principal and auxiliary radiators. This method provides a promising solution for achieving efficient frequency scanning with an in-band null-depth as high as −30 dB. Choi et al. offer miniaturised ultra-wideband circular polarised Koch fractal crossed dipole array. The design incorporates a Koch fractal structure and an extended metallic sidewall to stabilise the axial ratio (AR) across a wide bandwidth. This innovative approach has significant potential for phased array applications in ultra-wideband (UWB) circularly polarised environments. Xiong et al. present a novel millimetre-wave two-dimensional (2-D) wide-angle scanning phased array antenna based on decoupling surface. This paper proposes a millimetre-wave phased array antenna capable of wide-angle scanning based on decoupling surface (DS). This proposed design overcomes the challenges of mutual coupling between the antenna elements, enhancing the overall scanning range and efficiency of the antenna array. The proposed antenna exhibits promising capabilities for wide-angle beam-scanning implementation in scenarios such as automotive radar and satellite communication. Liang et al. contribute a high-efficiency wideband co-polarised metalens antenna. The paper demonstrates a multilayer metasurface structure comprising five layers of metal patches and four dielectric layers, forming a Fabry–Pérot resonator. This approach offers a compact solution for integrating metasurface technology with traditional antenna design, pushing the limits of antenna miniaturisation while maintaining its high efficiency. We would like to extend our sincere gratitude to the authors for their outstanding contributions, and to the reviewers for their insightful feedback, which significantly enhanced the quality of this Special Issue. Special thanks are also due to the editorial team at IET Microwaves, Antennas & Propagation for their invaluable support in managing this publication. Data available on request from the authors.

When array antennas are used for wide-frequency operation a difficulty with grating lobes is encountered at the upper frequency end of the operating band. This paper points out that the use of arrays for transmission and reception with different interelement spacings can be used to extend the operating frequency band in a radar system. The principle of transmitting-receiving arrays with different illuminations was used by Mattingly [2] to lower the sidelobe level of a radar array antenna. Birge [3] used it to reduce the number of elements in an array while preserving the resolution. The same principle is used in this paper to extend the operating frequency bandwidth of a radar antenna system. Relationships for an optimized radar array antenna system are derived. The criterion for optimization is the maximum bandwidth with a given total number of elements. It is shown that in an optimized system the number of elements in one array antenna is one greater than in the other, and the ratio of interelement spacings is inversely proportional to the square of the number of elements in the respective arrays. Based on these conditions, a function k is computed and tabulated. This function determines the number of grating lobes permissible in the specified angular sector, without overlap, as a function of the number of elements in the two arrays. An application to a high frequency (HF) ionospheric radar antenna system, now under construction, is used as an illustration of the principles outlined in the paper.

A new method of null synthesis in the antenna pattern of a phased array is discussed. The technique is based on the elevation of selected elements of the array. The elevation of the selected elements is obtained from the minimization of the power at the null locations. The results show the ability of this technique to achieve pattern nulling by controlling the elevation of selected elements while keeping the elevation of the insignificant elements unchanged, without changing the phases or the current amplitudes of the array elements.

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

Two high resolution beamformers, maximum entropy method (MEM) and Wagstaff‐Berrou broadband (WB2) [R. A. Wagstaff and J. Berrou, J. Acoust. Soc. Am. 75, 1133–1141 (1984)], were compared with each other and the standard FFT beamformer to determine performance degradation when the number of line array elements and the signal‐to‐noise ratio (SNR) were decreased. Experimental data from a multi‐tonal CW source recorded on an equally spaced horizontal line array were used to investigate the main beam broadening resulting from decreased SNR for SNR values ranging from 30 dB to near zero dB. Additional CW data from an equally spaced vertical line array were used to investigate the main beam broadening which resulted when the number of array elements was decreased successively from 31 to 16, 8, 4, and finally 2. Preliminary results indicate that the main beam broadening due to the decrease in array elements for both MEM and WB2 are similar and that both of these methods offer an order of magnitude decrease in the −3 dB beamwidth with respect to the standard FTT beamformer. [Work supported by Naval Electronic Systems Command, Code 612.]

Phased antenna arrays patterned on optical waveguides can strongly affect mode coupling and propagation in the waveguides. The unidirectional effective wavevector provided by the phased antenna array can facilitate phase matching between different waveguide modes; the effective wavevector can also breaks the symmetry of optical power flow in waveguides. These effects can be used to realize novel integrated photonic circuits. We used full-wave simulations to demonstrate broadband, small-footprint optical waveguide mode converters, polarization converters, and optical power diodes in the telecom and mid-infrared spectral ranges. The designed optical devices have small footprints (i.e., length of antenna arrays ranges from a few to ten times of the free-space wavelength). The efficiency of mode conversion (defined as the percentage of optical power coupled from one waveguide mode to the other) ranges from 10% to 60%, and the purity of converted modes approaches unity. The on-off ratio of optical power diodes (defined as the ratio between optical power transmission in two opposite directions) can be larger than 20dB over a broad wavelength range. We developed a coupled mode theory to model the asymmetric coupling between different waveguide modes and between waveguide modes and surface waves propagating along antenna arrays. The results calculated using the coupled mode theory can successfully explain mode evolution in our waveguide structures observed in simulations. We believe the platform of optical waveguides integrated with phased antenna arrays offers great opportunity to study novel physics originating from interaction between guided waves and designer structures. The platform also has great implication for integrated photonics device applications.

A 2 × 2 terahertz photoconductive antenna (PCA) array detector with high efficiency synthesis characteristic that improves the signal-to-noise ratio (SNR) of the detected signals has been reported in this paper. By processing the substrate material through a special micromachining process, the current signal generated by the adjacent antenna elements as opposed to that generated by the antenna gap is eliminated. Experiments show that the amplitude of the current signal output by the PCA array detector is consistent with the amplitude of the synchronous superposition of the current signals output by antenna elements, and the synthesis efficiency of the device achieves 93.7%. At the same time, the antenna array detector has low current noise, and its highest SNR is 62 dB under the excitation of different light energy, which is related to the number of antenna array elements.