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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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Faulty elements diagnosis of phased array antennas using a generative adversarial learning-based stacked denoising sparse autoencoder
摘要： Diagnosis of faulty elements in a linear phased array antenna is of great importance in the wireless communication field which has been received increasing attention. As a result of element or elements failure in the linear phased array antennas, the whole radiation pattern will suffer from high side lobe levels, wide bandwidth and unexpected nulls. To this end, we suggest a novel approach by combining the generative adversarial learning and the stacked denoising sparse autoencoder to determine the location of the faulty elements in antennas. The suggested approach can learn discriminative features from radiation pattern images adaptively and automatically with less expert knowledge. Meanwhile, the suggested approach is able to overcome the strong noise, the high dimensional size of the radiation pattern and the small fault samples. In this regard, the suggested approach possesses superiority in discriminant capability in contrast to the existing related approaches.
关键词： stacked denoising sparse autoencoder,phased array antennas,Faulty elements diagnosis,generative adversarial learning
更新于2025-09-23 15:22:29
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Compensation of Radome Effects in Small Airborne Monopulse Arrays by Convex Optimization
摘要： The quality of small array antennas in airborne monopulse systems can be significantly reduced by the radome. We therefore present a convex optimization approach to minimize radome effects in monopulse arrays. This is achieved by using active element patterns in the optimization to determine the excitation weights. Simulation results for a BoR array with 48 elements and an extended hemispherical radome are presented. We demonstrate that it is possible to reduce the side-lobe level by 3.5 dB by taking radome effects into account in the optimization. This approach also results in an increased gain, particularly at large scan angles. Furthermore, the presented approach allows the monopulse slope to be indirectly specified as a design parameter. It is shown that the trade-off between the monopulse slope coefficient and the side-lobe level is approximately linear.
关键词： radomes,airborne ESM,monopulse DOA estimation,convex optimization,phased array antennas
更新于2025-09-23 15:19:57
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Signal-to-Noise Ratio of True-Time Delay Beamformers Based on Microwave Photonic Links Using an Incoherent Broadband Optical Source
摘要： The signal-to-noise ratio (SNR) of true-time delay beamformers based on microwave photonic links using an incoherent broadband optical source (IBOS) is investigated. A comprehensive theory considering the bias angle of the Mach-Zehnder modulator employed in the microwave photonic link is presented to analyze the SNR. When the RF signal at the fundamental frequency is fed by the beamformer, the SNR is a function of the bias angle, the frequency of the applied RF signal, the modulation index, the system dispersion and the shape of the IBOS. We ?nd that by biasing the MZM near the minimum transmission point, the SNR at the fundamental frequency is maximized. On the other hand, by exactly biasing the MZM at the minimum transmission point, the RF signal at the double frequency can be fed by the beamformer with maximum power. The maximum SNR at the double frequency is a function of the frequency of the applied RF signal, the system dispersion and the shape of the IBOS while its dependence on the modulation index is eliminated. In both cases, the relationship between the SNR and the frequency of the RF signal, the system dispersion and the shape of the IBOS is also investigated. An experiment is carried out to verify the theoretical analysis, and the experiment results agree well with the calculation.
关键词： modulation,dispersion,true-time delay,incoherent broadband optical source,signal-to-noise ratio,Microwave photonics,phased array antennas
更新于2025-09-11 14:15:04