A N260 Band 64 Channel Millimeter Wave Full-Digital Multi-Beam Array for 5G Massive MIMO Applications

Abstract

In this paper, a 37-42.5GHz (N260 Band) 64 channel full-digital multi-beam array for 5G massive multiple input multiple output (MIMO) applications is developed. The multi-beam array is built on a time division duplexing (TDD) architecture in which the transmitter and receivers are independent and working separately to enable more flexible channel configuration and hardware distribution. The 64 antenna elements of the array are aligned in a way that 16 elements lie in the horizontal and 4 in the vertical direction to deliver higher beam resolution in the horizontal plane. By using cables of unequal lengths, the 16×4 antenna elements are connected to a cluster of 8 × 8 transmitters/receivers. The hardware design of the transmitters, receivers, antennas and other circuits is demonstrated, with excellent measured RF performance achieved. Furthermore, the calibration of the massive MIMO array is presented, and the influence of inequality of array feedlines on calibration accuracy in a wide bandwidth is analyzed and experimentally verified. Finally, experimental studies on single beam scanning, multiple concurrent beam generation and over-the-air (OTA) performance of the transmitting and receiving array have been done. Simulation and measurement results suggest that the array has an excellent beam-forming capability that supports beam steering and generation of multiple concurrent beams. The OTA test reveals that the array can provide high modulation and demodulation accuracy for communication.

The Role of Millimeter-Wave Technologies in 5G/6G Wireless Communications

“…Based on the methods to phase each antenna element, we can divide beamforming architectures for 5G wireless systems into three types: analog beamforming [28]- [37], full-digital beamforming [38]- [40], and hybrid beamforming [41]- [46] [see Fig. 4].…”

“…4(b), each antenna is directly connected to a transceiver chain, followed by an ADC/DAC with a high sampling rate and precision. A Q-band 64-channel full-digital beamforming transceiver for 5G communications has been proposed and implemented [40], covering a frequency range from 37 to 42.5 GHz [see Fig. 6].…”

“…On the other hand, for highly integrated up/down-converter systems, measuring the absolute phases from the DUT in the near-field could be difficult. Apart from adding additional hardware circuits [40], near-filed phaseless measurement is also a possible solution [153], [154]. It is based on the idea to reconstruct the phase information from the amplitudeonly data by using different phase retrieval approaches [155]- [157].…”

Broadband high‐gain slot grid array antenna for millimeter wave applications

“…It is undeniable that these applications will bring a revolutionary era of human life change taking advantage of the merits of mmW and enabling a new brand generation of communication systems, which has been clearly stated in the recently published White Paper of 5G. [1][2][3][4] It is admitted that mmW antennas often require advanced manufacturing technologies. For example, the grid array antenna (GAA) was firstly proposed by Kraus in 1964.…”

Improving energy efficiency in massive MIMO: joint digital beam‐steering and tone‐reservation PAPR reduction

“…In [10], however, the HBF is achieved by jointly optimising the DBF and ABF parts in order to comply with a set of constraints (defined by a spectral mask), also minimising the amplitude variation of the digital signals such that the PA in each RF chain can operate efficiently with a lower input back‐off (IBO). On the other hand, it is interesting to note that recent studies indicate that DBF can be efficiently implemented, and is in fact the most globally energy efficient approach in terms of achievable system throughput per energy consumption unit [6, 12].…”