Nonlinear Constrained Beamforming Algorithm for Circularly Polarized Phased Arrays

Fabiani, B. M.; Silveira, E. S.; Pina, Marcus Vinicius Pera de; Nascimento, Daniel C.

doi:10.1109/lawp.2018.2863544

Cited by 4 publications

(5 citation statements)

References 13 publications

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“…This process is carried out for all branches, resulting in the required coefficients to synthesize a given radiation pattern of an antenna array 5 . It is worth mentioning that this procedure may be repeated periodically to correct deviations in the complex weights due to temporal variations of the beamformer components and whenever it is necessary to change the array radiation pattern.…”

Section: Beamformer Architecture and Analysismentioning

confidence: 99%

“…Phased arrays have been an important research area of microwave engineering since the 1960s, 1 mostly due to their capabilities to steer the main beam 2– 4 and to synthesize radiation patterns with nulls at a given set of angles 5–8 or with multibeam configuration, 9–11 listed as an illustration of phased arrays versatility. Designed mainly for military applications, 1 active electronically scanned arrays (AESA) were considered sensitive technology until the last few years and only recently they have been used in civilian applications, such as 5G communication systems 12–16 and mobile systems 17,18 .…”

Section: Introductionmentioning

confidence: 99%

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Closed‐loop controlled microwave beamformer

Fabiani

Oliveira

Vieira

et al. 2021

Int J RF Mic Comp-Aid Eng

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This article presents the design and tests of a closed‐loop controlled microwave beamformer for phased arrays. The proposed circuit owns an internal reference signal used to automatically set predefined amplitudes and phases of the beamformer branches. This signal is applied to the branches through directional couplers with high directivity and propagates in them similar to the actual signals coming from the antenna array. As a consequence of this architecture, we found that the impedance mismatch between the antennas and the beamformer as well as the mutual coupling in the array is taken into account during calibration, resulting in a more accurate adjustment of amplitudes and phases. In this work, the influence of the mutual coupling between the antennas and the directivity of the couplers on the beamforming calibration uncertainty is also analyzed. From the derived uncertainties, the corresponding pattern degradation is evaluated by performing Monte Carlo simulations. It is shown that using couplers with low directivity together with tightly coupled arrays can produce undesirable main lobe squints of up to 4.5°, main lobe level deviations of up to 4.2 dB, and side lobe level variations of up to 24 dB. On the other hand, the use of high directivity couplers can mitigate these problems. Lastly, the validation of the designed circuit is conducted in two stages: bench tests and measurements in an anechoic chamber with an array of six printed monopoles operating at 2.2 GHz. Amplitude and phase calibration errors less than 0.5 dB and 3°, respectively, were observed in the bench tests.

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Section: Beamformer Architecture and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Closed‐loop controlled microwave beamformer

Fabiani

Oliveira

Vieira

et al. 2021

Int J RF Mic Comp-Aid Eng

Self Cite

View full text Add to dashboard Cite

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“…At present, beamforming algorithm [15][16][17][18] is mostly used in sound source positioning. Nascimento et al [19] proposed a beamforming algorithm based on the least squares problem under non-linear constraints. Wang et al [20] applied asynchronous measurements of microphone arrays to 3-D beamforming.…”

Section: Introductionmentioning

confidence: 99%

“…Nascimento et al. [19] proposed a beamforming algorithm based on the least squares problem under non‐linear constraints. Wang et al.…”

Section: Introductionmentioning

confidence: 99%

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Optimization scheme of partial discharge location of external insulation based on 2‐D multiple signal classification algorithm

Pei

Liu

et al. 2022

IET Science Measure & Tech

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Partial discharge (PD) localization is critical to ensure the safe operation of power equipment. In this paper, an optimization scheme is developed for PD positioning of external insulation equipment. The optimization scheme is based on an eight‐element cross sensor array to receive the ultrasonic signal generated by the PD, and uses the highly accurate 2‐D multiple signal classification (2‐D MUSIC) algorithm to locate the signal. Simulated discharge signal is adopted to test the optimization scheme, and the results show that the positioning error is less than 0.61° when the signal‐to‐noise ratio (SNR) is above −5 dB. In addition, three discharge models are tested at various locations. The average azimuth errors are 0.9°, 1.9°, and 1.55° for the needle‐plate, cone‐plate, and ball‐plate discharge models, respectively, and the average pitch angle errors are 0.75°, 2.1°, and 1.4°, respectively. These show that the needle‐plate model has the best positioning effect. Simulations and experiments are also carried out on the double discharge source scenario, and the error is within 2.2°. A PD location visualization equipment based on the proposed optimization scheme is developed and applied on‐site. The equipment is capable of satisfying the requirements of operation and maintenance.

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