Coupler Integrated Microstrip Patch Linear Phased Array for Self-Calibration

Chae, Soo-Chang; Jo, Hye-Won; Oh, Ju-Ik; Kim, Ghoo; Yu, Jong‐Won

doi:10.1109/lawp.2020.3011862

Cited by 22 publications

(12 citation statements)

References 17 publications

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“…For the S-band digital array testbed at Lincoln Laboratories, a coupler was used for injecting in front of the LNAs for receive-only calibration monitoring [86]. In [87], a coupled line network that is weakly coupled to the antenna array is designed to provide a calibration signal path without adding any switch after the antenna port.…”

Section: The Built-in Network Methodsmentioning

confidence: 99%

“…Some methods such as the near-field scanning probe method and the peripheral fixed probe method require additional equipments [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60], while the mutual coupling method takes advantage of the inherent property of the phased array without the need for extra hardware [61][62][63][64][65][66][67][68][69][70][71]. For Si-based integrated phased array antenna, it's very common to design a dedicated coupling network that using transmission lines connected to each antenna element for periodic in-field calibration [72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87]. Moreover, different trade-off strategies can be made between the complexity of measurement setup and signal process- ing require...…”

Section: Introductionmentioning

confidence: 99%

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Impact Analysis and Calibration Methods of Excitation Errors for Phased Array Antennas

Gao

Zhang

2021

IEEE Access

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Phased array antennas have played a very important role in many different areas and applications. It requires precise excitation of each antenna element by various synthesis techniques to obtain desired array pattern features. However, due to reasons such as manufacturing imperfections, component aging, and temperature variation, the realistic antenna element excitation inevitably differs from their expected values in practice. This paper presents a tutorial-like review to deal with excitation errors for phased array antennas. Two kinds of analysis methods, probabilistic methods and interval arithmetic (IA) based methods, are presented to evaluate the effects of excitation errors for phased array antennas. State-ofthe-art calibration methods along with various signal processing techniques are reviewed, their advantages and challenges are discussed in a comparative manner. Some other common errors and open research directions are also presented.INDEX TERMS Phased array antenna, excitation error, interval arithmetic, array calibration.

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Section: The Built-in Network Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact Analysis and Calibration Methods of Excitation Errors for Phased Array Antennas

Gao

Zhang

2021

IEEE Access

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“…Reference 40, for example, uses a low‐directivity simple coupler to apply the reference signal, but it is a source of inaccuracy for the calibration, as will be further shown here. A similar analysis is carried out in Reference 36, which presents the errors in the calibration caused by switches implemented with variable attenuators, however, both the array mutual coupling and the impedance mismatches were not considered in that study.…”

Section: Introductionmentioning

confidence: 96%

“…In the literature, there are found four calibration methods to deal with this problem 24,25 . They are classified as near‐field scanning probe, 26,27 mutual coupling method, 28–31 peripheral fixed probe, 32–35 and built‐in network method 36–41 …”

Section: Introductionmentioning

confidence: 99%

“…The literature review reveals that the analysis of the uncertainty in the calibration process as a function of the directivity of the couplers and the array mutual coupling is not addressed in the previous works concerning the built‐in network method, 36–41 which makes it a relevant topic for investigation. Reference 40, for example, uses a low‐directivity simple coupler to apply the reference signal, but it is a source of inaccuracy for the calibration, as will be further shown here.…”

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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