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Phased Transmitarray Antennas for 1-D Beam Scanning
摘要： A transmitarray antenna (TAA) fed by a phased array antenna (PAA) for one-dimensional (1-D) beam scanning is proposed at 10 GHz in this letter. The TAA is composed of two types of elements, i.e., the hexagonal subwavelength low-pass elements as well as the pure dielectric ones. The PAA feed is a 1-D printed dipole array loaded with the short-circuited dummy ones. The proposed PAA-fed TAA, with a feeding distance to TAA diameter ratio (H/D) of mere 0.375, achieves a peak simulated gain of 25.6 dBi at 0o scanning (corresponding to peak aperture efficiency of 57.5%) and a 3.13 dB gain drop for ±30o beam scanning, along with a ~2-dB beam crossover. The measured results agree reasonably well with the simulated ones, validating the proposed design.
关键词： periodic structures,phased array antennas,transmitarray antennas,Beam scanning
更新于2025-09-23 15:22:29
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Effectiveness of phased array focused ultrasound and active infrared thermography methods as a nondestructive testing of Ni-WC coating adhesion
摘要： The substrate/coating adhesion is a crucial parameter conditioning the quality of coating and its durability in service. For this reason, an inspection of the coating integrity, in particular, the presence of adhesion defects will be of great importance. The adhesion inspection is usually ensured by destructive methods, such as traction, interfacial indentation, four-point bending, testing scratch, etc. However, it is currently hampered by the absence of a satisfactory non-destructive method. Among the non-destructive testing technologies widely used in the industrial field, there are X-ray diffraction, ultrasonic inspection, and infrared thermography. In this paper, two methods are investigated: ultrasonic inspection, which becoming more efficient, especially with the emergence of phased array systems that allow to investigate different inspection angles and focusing depths, and the active infrared thermography. Experiments were performed on metallic coatings deposited on a mild steel substrate. Coatings were containing artificial defects (flat bottom holes with different diameters) at the interface and others were exempts of defects. Longitudinal waves with specific delay laws were generated through a phased array contact transducer (5 MHz of central frequency). Experimental results show that the ultrasonic method allows detecting and sizing defects with a diameter of 1 mm located in thick coatings.
关键词： Substrate/coating adhesion,phased array,defects,detection,nondestructive testing,coating
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Photonics Conference (IPC) - Reston, VA (2018.9.30-2018.10.4)] 2018 IEEE Photonics Conference (IPC) - High-Power Photonic Phased Array Antennas
摘要： We review recent work on a new antenna concept— the high-power photonic phased array. By integrating high-power photodiodes proximal to the transmit aperture’s radiating elements, dense, lightweight, and broadband array designs are realized. Several manifestations of this idea are discussed, emphasizing different application-specific design choices.
关键词： RF photonics,ultra-wideband (UWB),photonic antenna,phased array antenna,5G,high-power photodiode,millimeter wave (mmW)
更新于2025-09-23 15:22:29
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A shared aperture 1-bit metasurface for orbital angular momentum multiplexing
摘要： In this letter, a shared aperture 1-bit metasurface for orbital angular momentum (OAM) multiplexing is studied. A phased array antenna fed by the phase shift network is embedded on the reflective aperture of the 1-bit metasurface. The proposed device can work on reflectarray mode from 7.1GHz to 7.5GHz and phased array mode from 7GHz to 7.5GHz. Correspondingly, OAM vortex beam with topological charge l = -1 and l = 1 can be generated. The transmission coefficient between the two working modes is below -30dB and the envelop correlation coefficient (ECC) is quite close to 0, which reveals the excellent isolation and diversity performance. A prototype of the proposed device is fabricated and tested. The measured S parameters and radiation patterns agree well with the simulation results.
关键词： phased array,reflectarray,metasurface,Orbital angular momentum (OAM) multiplexing
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Shenzhen, China (2018.7.13-2018.7.15)] 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Design of All-Metal Vivaldi Phased Array Antenna
摘要： A wideband phased array antenna consisted of all-metal Vivaldi is designed in this paper. It is a line array with 8 Vivaldi elements, at the ends of the array there are two additional elements added as the virtual elements to constitute the array environment. The antenna is comprised of the slot line structure and SMA connector, so that it is convenient to process, the size of the array is 150mm × 35mm. The simulated and measured results show that the VSWR (voltage standing wave ratio) of the array antenna in the 6 ~ 12 GHz band is less than 2.5, and the phase scanning of 45-degree angle can be realized in this band.
关键词： phased array,wide scanning angle,wideband,all-metal vivaldi antenna
更新于2025-09-23 15:22:29
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mmWave CMOS Power Amplifiers for 5G Cellular Communication
摘要： This article covers the basics of millimeter-wave PA design in CMOS technology for integrated phased arrays, targeting the upcoming 5G new radio (NR) cellular communication standard. Key PA figures of merit, as well as application of beam-forming phased arrays to combine power over-the-air, are briefly reviewed. Then, starting from practical handset form factor constraints and system-level drivers, CMOS-specific technological and design-related challenges are conceptually illustrated using a simple single-transistor PA. A survey of the state-of-the-art is presented to give examples of the challenges and illustrate the PA techniques used to tackle them in linear 28-GHz CMOS PAs for 5G NR.
关键词： beam-forming,efficiency,linearity,millimeter-wave,power amplifier,phased array,CMOS,5G
更新于2025-09-23 15:22:29
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - An Automatically Steering Optical Beam-Forming Network for Phased Array Antenna Based on Dense Wavelength Division Multiplexing
摘要： It is proposed an automatically steering optical beam-forming network (OBFN), which is consisted of an optical fiber loop structure. The loop structure is composed by an optical switch, an optical fiber splitter, and an optical true time delay lines based on dense wavelength division multiplexing (DWDM). The channel number of the DWDM is matched with the number of the phased array antennas (PAA). The true time delay difference between two adjacent channels is set as a basic step. And the optical wave modulated by radio frequency (RF) signal can run into the loop and suffer increased delay with increased circles. Thus the PAA is steered automatically without additional controlling and programming. The performance of this design is analyzed with its maximal circle numbers and the splitting ratio of the optical splitter in theory. The concept-proof experiments with 8 optical channels for DWDM are carried out and the simulation of the PAA radiation pattern is given.
关键词： optical switch,optical beam-forming network,optical fiber loop,optical controlled phased array radar,wavelength division multiplexing
更新于2025-09-23 15:22:29
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - The Realization of ISAR Imaging in Multifunction Wideband Phased Array Radar
摘要： Multifunction wideband phased array radar (MWPAR) is an integrated ground based radar which enables multi-function capabilities to meet the forthcoming surveillance and reconnaissance tasks of air targets. The main functions of the MWPAR system include moving target detection and tracing, high resolution imaging and EW. The variety of functions can be fulfilled by the use of a share wideband, multi-beam AESA aperture and a common multi-channel high-speed data acquisition and signal processing system. The real-time ISAR Imaging of maneuvering targets in MWPAR is discussed in this thesis, an advanced signal processing platform and high speed data transmission system based on VPX bus is used to meet the real-time requirement and multifunction scheduling, an improved velocity compensation algorithm of maneuvering targets is adopted to reduce the computational complexity. The simulation results are used to confirm the effectiveness of the proposed methods.
关键词： Wideband,Multifunction,ISAR,Phased Array
更新于2025-09-23 15:22:29
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Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber Based C-RANs
摘要： As a key technique of supporting the fixed backbone network, radio over fiber (RoF) systems transmit the radio frequency signals over optical fiber in order to take advantage of their large available bandwidth. In this context, optical fiber aided phased antenna array (PAA) based beamforming techniques have attracted substantial research interest with the goal of improving the cell-edge coverage of cellular base stations. In this paper, we conceive a novel optical fiber aided beamforming technique based on the fiber's nonlinearity to be applied in cloud radio access network (C-RAN). In our proposed technique, the PAA elements are fed by the phase-shifted signals introduced by our highly nonlinear fiber (HNLF) aided phase-shifting solution, which results in an angular beamsteering range of around 90°. This can be exploited by sectorization in cellular networks to reduce the cochannel interference imposed. Furthermore, we exploit the proposed RoF-aided phase shifting technique in C-RAN, where our proposed system takes advantage of the centralized signal processing capability of the RoF system to conceive an all-optical processing based tunable beamforming system. While our flexible HNLF-aided phase-shifting process is confined to the central office of the C-RAN, the end users in the C-RAN cellular networks are capable of flexibly choosing the serving remote radio heads (RRHs) and employing diverse wireless transmission techniques. Through integrating our HNLF-aided phase-shifting design into the proposed C-RAN, we impose as little as 0.1 dB signal-to-noise Ratio (SNR) degradation compared to its traditional electronic counterpart, which requires extra phase-shifters.
关键词： phase-shifter,self-phase modulation,phased array antenna beamforming,C-RAN,cross-phase modulation,highly nonlinear fiber,Optical fiber,optical nonlinearity
更新于2025-09-23 15:22:29
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A Low-cost Ka-band Circularly Polarized Passive Phased-Array Antenna for Mobile Satellite Applications
摘要： This paper presents a low-profile, high-performance, and low-cost Ka-band circularly polarized (CP) passive phased-array antenna (PAA) system. A 1 × 4 passive sub-array operating at the Ka-band frequency band is investigated, developed, and tested as a possible building block for mobile satellite communication systems. In particular, a CP antenna integrated with a high-performance passive phase shifter is presented and experimentally verified. A new low-cost and low-profile magnetic actuator is proposed to precisely control the phase state of the phase shifter. A 3-D printed polymer package is utilized to enclose the phase shifter and reduce the environmental effects. The proposed CP passive PAA achieves high performance right hand circularly polarized (RHCP) radiation with high cross-polarization discrimination over a wide scan angle from 0o to ±38o over the frequency band (29.5-30.5 GHz). An AR < 3dB is demonstrated over the entire scanning range. Moreover, the measured radiation efficiency is 60% at bore-sight. The gain drops by 1 dB at ±38o scanning angles.
关键词： satellite mobile communication,millimeter-wave phased-array antenna,phase shifter,Circularly polarized antenna
更新于2025-09-23 15:21:21