Inter-Stream Loopback Calibration for 5G Phased-Array Systems

Aoki, Yuuichi; Kim, Yong‐Hoon; Hwang, Yongan; Kim, Sunryoul; Dao, Manh Tuan; Kang, Daehyun; Minn, Donggyu; Kang, Hyunbum; Park, Hyun-Chul; Ryu, An-Sang; Jeon, Sanghyun; Yang, Sung-Gi

doi:10.1109/rfic49505.2020.9218341

Cited by 8 publications

(2 citation statements)

References 8 publications

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“…12(b), or vice versa for all transmitters. In [120], a star topology loopback scheme was used to bind all the RF nodes into a single node with 16-way combiners as shown in Fig. 12(c).…”

Section: Imperfection Of Antenna Channelsmentioning

confidence: 99%

Terahertz Communications: Challenges in the Next Decade

Song

Lee

2022

IEEE Trans. THz Sci. Technol.

174

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Thanks to the abrupt advances in semiconductor technologies, particularly in terms of the operating frequency, the last decade has seen various efforts and trials in attempts to achieve high-throughput wireless communications at terahertz (THz) frequencies. Through the use of several potential device technologies, not only III-V heterojunction bipolar and high-electron-mobility transistors but also silicon complementary metal-oxide-semiconductors and photonic technologies, high data rates of 100 Gbps or more have been successfully demonstrated. Meanwhile, the next generation of wireless communications systems, so called 6G, is already being discussed in research communities worldwide. A terabit per second peak data rate is envisioned, which essentially requires huge spectral resources. The recent considerable attention to 6G communications is implicitly focused on THz communications but is more than a technical curiosity unlike in the past. In this article, we briefly review the progress of THz communications made in the last decade and discuss some of the most challenging issues that need to be overcome for future wireless systems at THz frequencies, including not only the 6G network but also short-range connectivity and fixed wireless links.

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“…12(b), or vice versa for all transmitters. In [120], a star topology loopback scheme was used to bind all the RF nodes into a single node with 16-way combiners as shown in Fig. 12(c).…”

Section: Imperfection Of Antenna Channelsmentioning

confidence: 99%

Terahertz Communications: Challenges in the Next Decade

Song

Lee

2022

IEEE Trans. THz Sci. Technol.

174

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“…Third, monitor photodiodes should be included in future implementations of the OBFN to determine the switch voltages in real time and to make the circuit more robust to temperature or wavelength variations. By providing a loopback [61] to the central office, the monitor PDs also facilitate antenna system calibration, ensuring optimal performance of the RAUs as well as the tight time/phase synchronization among them when combined with over-the-air (OTA) calibration techniques [62]. Adding these monitor PDs can be done by migrating the design to imec's full Si-Photonics platform iSiPP50G that includes passive and active components, or by making use of transfer printing to print the PDs on top of the grating couplers currently used for calibration of the circuit [63].…”

Section: State Of the Art And Future Workmentioning

confidence: 99%

Air-Filled SIW Remote Antenna Unit With True Time Delay Optical Beamforming for mmWave-Over-Fiber Systems

Paula

Bogaert

Caytan

et al. 2022

J. Lightwave Technol.

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A low-complexity and efficient mmWave-over-fiber remote antenna unit (RAU) is proposed that enables broadband transmission and wide-angle squint-free beam steering in the full [26.5-29.5] GHz n257 5G band. It leverages an in-house developed optical beamforming network (OBFN), implemented on a silicon photonics integrated circuit, and a broadband optically enabled 1x4 uniform linear array (ULA), enabling grating-lobe-free beam steering between [-50 • , 50 • ]. The antenna elements (AEs) of the ULA are implemented in air-filled substrate-integratedwaveguide technology. They adopt a novel improved aperturecoupled feeding scheme to achieve high efficiency, high isolation and minimal back radiation over a broad frequency band. Each AE is compactly integrated and co-optimized with a dedicated opto-electrical transmit chain, maximizing the RAU's performance, including beamforming flexibility and energy efficiency, while minimizing its size. The separately packaged OBFN implements true-time-delay beamforming by means of four switchable optical delay lines that are capable of discretely tuning the delay difference between AEs with a resolution of 1.6 ps, up to a maximum delay of 49.6 ps to fully exploit the ULA's full grating-lobe-free scan range. Measurements show that the AEs are excellently matched in the [25.1-30.75] GHz band, exhibit high isolation (>15 dB) in the operating band, and feature a stable peak gain of 6.8±0.72 dBi with a beamwidth of at least 95 • . Additionally, optical beamforming was successfully demonstrated by steering the RAU's beam towards angles up to 51.8 • , with a maximum gain degradation below 0.6 dB. Finally, the optically enabled 1×4 ULA successfully establishes a 64-QAM wireless communication link at 2.2 Gbaud (13.2 Gbps) while beam steering up to 50 • with an error vector magnitude below 7.6%.

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Built-In Self-Test of Millimeter-Wave Integrated Front-End Circuits: How Far Have We Come?

Wenger,

Meinerzhagen,

Issakov

2024

IEEE Access

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With automotive radar and 5G/6G communications, mass-market applications for millimeterwave circuits in silicon technologies have been identified or established in recent years. For high-volume, millimeter-wave integrated circuits, operating roughly between 30 GHz and 300 GHz, testability is a major concern, both from an overall cost as well as a quality assurance perspective. A solution for cost effective, low-overhead test of millimeter-wave integrated circuits is the integration of built-in self-test (BIST) features into the high-frequency front-end. Because BIST is an emerging topic in high-frequency circuit design, the field is still very fragmented. A plethora of different system concepts as well as building blocks have been proposed in recent years. This paper tries to provide a comprehensive overview of the state of the art in millimeter-wave BIST in an attempt to drive the field towards identification of standardized self-test solutions.INDEX TERMS Built-in self-test, CMOS, millimeter-wave transceivers, SiGe, silicon.

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Inter-Stream Loopback Calibration for 5G Phased-Array Systems

Cited by 8 publications

References 8 publications

Terahertz Communications: Challenges in the Next Decade

Terahertz Communications: Challenges in the Next Decade

Air-Filled SIW Remote Antenna Unit With True Time Delay Optical Beamforming for mmWave-Over-Fiber Systems

Built-In Self-Test of Millimeter-Wave Integrated Front-End Circuits: How Far Have We Come?

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