A Delay-Based LO Phase-Shifting Generator for a 2-5GHz Beamsteering Receiver in 28nm CMOS

Antonov, Yury; Valkama, Mikko; Kosunen, Marko; Ryynänen, Jussi; Zahra, Mahwish; Stadius, Kari; Khonsari, Zahra; Kempi, Ilia; Miilunpalo, Toni; Inkinen, Juha; Unnikrishnan, Vishnu; Anttila, Lauri

doi:10.1109/esscirc.2019.8902864

Cited by 4 publications

(8 citation statements)

References 13 publications

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“…The resolution of the tunable delay ∆τ , which dictates the beam direction resolution, is directly set by the used DDL. As an example, [3] presents a beamformer based on LO phase shifting implemented with DDLs. The DDL achieves picosecond delay resolution, which maps to a beam resolution of 2.4 degrees at 5 GHz, with a power consumption of 11 mW.…”

Section: Delay Resolutionmentioning

confidence: 99%

“…The proposed solution realizes beamforming delays by re-sampling the discrete-time output signal from the passive mixer of a direct conversion receiver during its hold period. Inclusion of a re-sampling stage extends the local oscillator (LO) phase shifting, like the one implemented in [3], to a true-time-delay beamformer. The beamforming delays are controlled by tuning the relative delay between the LO and the re-sampler clock.…”

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confidence: 99%

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True-Time-Delay Beamforming Receiver With RF Re-Sampling

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Unnikrishnan

Zahra

et al. 2020

IEEE Trans. Circuits Syst. I

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Analog domain true-time-delays (TTD) are desired in hybrid beamforming receivers with large relative bandwidths to mitigate the problem of beam squint. We propose a true-timedelay beamforming receiver architecture which enables squintfree wideband spatial filtering prior to the A/D conversion. The receiver implements true-time-delay with delayed re-sampling of the discrete-time output of a passive mixer. The receiver has the capability to extend the range of the beamforming delays from one to several carrier periods of the RF signal with pulse-skipped local oscillator (LO) signals, thereby enabling TTD beamforming with large antenna arrays. Further, a polyphase structure with parallel mixers is proposed to prevent spectral aliasing resulting from the lowered sample rate of the pulse-skipped LO signals. In addition, the maximum beamforming delay scales with the LO frequency, supporting large arrays also at low frequencies where the antenna separation set by the wavelength is large. We verify the proposed concepts with transistor-level simulation of the receiver implemented with a 28-nm CMOS process. The design achieves a squint-free beamforming for a 400 MHz RF bandwidth, and a maximum beamforming delay of three carrier time periods. The power consumption for a 3 GHz carrier frequency is 4 mW per antenna.

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Section: Delay Resolutionmentioning

confidence: 99%

mentioning

confidence: 99%

True-Time-Delay Beamforming Receiver With RF Re-Sampling

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Unnikrishnan

Zahra

et al. 2020

IEEE Trans. Circuits Syst. I

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“…Any of the four antennas can be connected to either of the sensing ADCs through a switch matrix amplifier. Delay characterization with the FFT units provides delay information for digitally-controlled beamsteering implemented with digitally-controlled delay lines [16], [17]. The proposed tuning structure provides wide frequency band for LO phase-shifting architecture.…”

Section: Receiver Implementationmentioning

confidence: 99%

“…The four distinct delays are combined using AND gates to generate four 25% duty cycle nonoverlapping LO waveforms. The branched structure reduces the power consumption in comparison to architectures with frequency divider that require four fully independent signal paths, and imbalances between IQ signals [16].…”

Section: Lo Phase Tuningmentioning

confidence: 99%

“…The designed apparatus utilizes two parallel sets of ADC and FFT units, where one set serves as a primary calibration channel and other as a zero-delay reference, enabling digitally-assisted self-test for estimation of relative delays between receiver paths. The on-chip section of delay estimator is an extension of our prior work [16] about the RF blocker detector, both of these functions can be performed with this hardware. The RF signal can be passed to the undersampling ADC output of any LNTA via specialized switch matrix amplifier, which consists of source followers and tri-state buffers (Fig.…”

Section: Delay Estimationmentioning

confidence: 99%

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A 2–5.5 GHz Beamsteering Receiver IC With 4-Element Vivaldi Antenna Array

Zahra

Kempi

Haarla³

et al. 2020

IEEE Trans. Microwave Theory Techn.

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In this paper we present a 4-element Vivaldi antenna array and beamsteering receiver IC for fifth-generation mobile network (5G) New Radio (NR). The implemented receiver utilizes a delay-based local-oscillator (LO) phase-shift technique for accurate beamsteering, and it exhibits 1 to 2.4 degree phase tuning capability for 2-5 GHz bandwidth accordingly. On-chip delay measurement is performed with pilot signal generation and delay estimation capable of 2 ps accuracy. The IC is fabricated on 28 nm CMOS technology, it occupies an area of 1.4 × 1.4 mm 2 including bonding pads and consumes 22.8 mW at 2 GHz for single receiver path operation. The receiver demonstrates wideband over-the-air reception with the prototype antennas.

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