A Miniaturized Butler Matrix Based Switched Beamforming Antenna System in a Two-Layer Hybrid Stackup Substrate for 5G Applications

Kim, Soyeon; Yoon, Seongjo; Lee, Yongho; Shin, Hyunchol

doi:10.3390/electronics8111232

Cited by 38 publications

(34 citation statements)

References 17 publications

(68 reference statements)

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“…The optimized designs from Section 4.1 and Section 4.2 have been compared in terms of size and performance with other planar BMs from the literature [ 16 , 21 , 23 , 27 , 28 , 29 , 30 ]. Whenever possible (all benchmark designs except the one reported in [ 28 ]), the performance figures have been obtained based on the EM simulation results.…”

Section: Numerical Results and Experimentsmentioning

confidence: 99%

Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences

Bekasiewicz

Koziel

2021

Sensors

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Design of Butler matrices dedicated to Internet of Things and 5th generation (5G) mobile systems—where small size and high performance are of primary concern—is a challenging task that often exceeds capabilities of conventional techniques. Lack of appropriate, unified design approaches is a serious bottleneck for the development of Butler structures for contemporary applications. In this work, a low-cost bottom-up procedure for rigorous and unattended design of miniaturized 4 × 4 Butler matrices is proposed. The presented approach exploits numerical algorithms (governed by a set of suitable objective functions) to control synthesis, implementation, optimization, and fine-tuning of the structure and its individual building blocks. The framework is demonstrated using two miniaturized matrices with nonstandard output-port phase differences. Numerical results indicate that the computational cost of the design process using the presented framework is over 80% lower compared to the conventional approach. The footprints of optimized matrices are only 696 and 767 mm2, respectively. Small size and operation frequency of around 2.6 GHz make the circuits of potential use for mobile devices dedicated to work within a sub-6 GHz 5G spectrum. Both structures have been benchmarked against the state-of-the-art designs from the literature in terms of performance and size. Measurements of the fabricated Butler matrix prototype are also provided.

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Section: Numerical Results and Experimentsmentioning

confidence: 99%

Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences

Bekasiewicz

Koziel

2021

Sensors

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“…Various mm-wave switched-beam antenna systems based on the Butler matrix have been reported previously, including [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ] in Ka-band and [ 13 , 14 , 15 ] in V-band. All of them carefully investigated co-integrated designs and implementations of an array antenna and Butler matrix.…”

Section: Introductionmentioning

confidence: 99%

“…The mm-wave band design should critically include co-integrated design and implementation processes with full considerations on the inter-connection and inter-coupling issues among the building components. However, none of the previous works [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] had successfully shown the co-integration of a switch in their antennas. Without incorporating a switch, they only could characterize their antennas by exciting one port of N × N Butler matrix, while terminating other ports with 50-Ω matching resistors [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

A 28-GHz Switched-Beam Antenna with Integrated Butler Matrix and Switch for 5G Applications

Lee

Shin

2021

Sensors

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This work presents a 28-GHz Butler matrix based switched-beam antenna for fifth-generation (5G) wireless applications. It integrates a 1 × 4 microstrip antenna, a 4 × 4 Butler matrix, and a single-pole four-throw (SP4T) absorptive switch in a single planar printed circuit board and is housed in a metal enclosure. Co-integration of a packaged switch chip with the Butler matrix based switched-beam antenna greatly enhances the form factor and integration level of the entire system. A wideband two-section branch line coupler is employed to minimize the phase and magnitude errors and variations of the Butler matrix. The aluminum metal enclosure stabilizes the electrical performances, reduces the sidelobes, and improves the structural stability. The fabricated antenna with the metal enclosure assembled has a dimension of 37 × 50 × 6.2 mm3. With an RF input signal fed to the antenna’s input port through a single Ka-band connector, and the switching states chosen by 2-bit dc control voltages, the antenna successfully demonstrates four directional switched beams. The beam switching operations are verified through the over-the-air far-field measurements. The measured results show that the four beam steering directions are −43°, −17°, +10°, +34° with side lobe levels < −5.3 dB at 28 GHz. The antenna also shows reasonably wideband radiation patterns over 27–29 GHz band. The 10-dB impedance bandwidth is 25.4–27.6 GHz, while a slightly relaxed 8-dB bandwidth is 25.2–29.6 GHz. Compared to previous works, this four-directional switched-beam antenna successfully exhibits the advantages of high integration level and satisfactory performances for the 28-GHz 5G wireless applications.

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“…Thus, to effectively reconfigure beam patterns, the Butler matrix can be a good candidate since the limited scan angles can be compensated by the aerial mobility of UAVs. Moreover, effective uses of the Butler matrix have been demonstrated in mmWave and 5G applications [26][27][28][29]. Therefore, in this paper, a new array architecture based on folded ground structures for UAV applications is presented.…”

Section: Introductionmentioning

confidence: 99%

Compact Switched-Beam Array Antenna with a Butler Matrix and a Folded Ground Structure

Kim

Dong

et al. 2019

Electronics

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A compact switched-beam array antenna, based on a switched Butler matrix with four folded ground antennas, is presented for unmanned aerial vehicle (UAV) applications. The folded ground structure, including a slotted patch radiator surrounded by multiple air-gapped ground layers, is adopted to maximize compactness. The extra ground layers provide extra capacitive coupling around the patch antenna, resulting in a down-shift of resonant frequency and a reduction in the antenna size. Also, to optimize aerial operation with a wider beam coverage, the 1 × 4 array is integrated with a switched Butler matrix controlled by a microcontroller unit (MCU). The choice of the Butler matrix reduces the complexity of beamforming circuitry and avoids the use of high-cost phase shifters requiring extra control-bit signals. Further, the array antenna is optimized for high isolation among the antenna ports and a minimal UAV body effect. Then, the proposed structure was verified at 1.96 GHz for test purposes only, and the array size, excluding the antenna case, was 2.16λo × 0.54λo × 0.07λo. The measured 10 dB impedance bandwidth for all antenna elements in the array was always better than 3.4%, and the isolation among the antenna ports was also better than 19 dB. The measured peak gain, excluding the loss of the switched Butler module, was about 9.98 dBi, on average. Lastly, the measured peak scan angles were observed at −39°, −17°, 9° and 31° according to switching modes.

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A Miniaturized Butler Matrix Based Switched Beamforming Antenna System in a Two-Layer Hybrid Stackup Substrate for 5G Applications

Cited by 38 publications

References 17 publications

Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences

Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences

A 28-GHz Switched-Beam Antenna with Integrated Butler Matrix and Switch for 5G Applications

Compact Switched-Beam Array Antenna with a Butler Matrix and a Folded Ground Structure

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