A CMOS Dual-Polarized Phased-Array Beamformer Utilizing Cross-Polarization Leakage Cancellation for 5G MIMO Systems

Abstract

This article introduces a power-efficient and lowcost CMOS 28-GHz phased-array beamformer supporting fifthgeneration (5G) dual-polarized multiple-in-multiple-out (MIMO) (DP-MIMO) operation. To improve the cross-polarization (crosspol.) isolation degraded by the antennas and propagation, a power-efficient analog-assisted cross-pol. leakage cancellation technique is implemented. After the high-accuracy cancellation, more than 41.3-dB cross-pol. isolation is maintained along with the transmitter array to the receiver array. The element-beamformer in this work adopts the compact neutralized bi-directional architecture featuring a minimized manufacturing cost. The proposed beamformer achieves 22% per path TX-mode efficiency and a 4.9-dB RX-mode noise figure. The required onchip area for the beamformer is only 0.48 mm 2 . In over-the-air measurement, a 64-element dual-polarized phased-array module achieves 52.2-dBm saturated effective isotropic radiated power (EIRP). The 5G standard-compliant OFDMA-mode modulated signals of up to 256-QAM could be supported by the 64-element modules. With the help of the cross-pol. leakage cancellation technique, the proposed array module realizes improved DP-MIMO EVMs even under severe polarization coupling and rotation conditions. The measured DP-MIMO EVMs are 3.4% in both 64-QAM and 256-QAM. The consumed power per

Terahertz Communications: Challenges in the Next Decade

“…Thanks to the highly directive beam, the THz channels rarely exhibit fading or frequency-selective responses, which means polarization multiplexing schemes that provide even larger data capacities can be used. However, it is hard to maintain the orthogonality of two polarization states in the transceivers, and thus the imperfect signal isolation should be measured and compensated for as well [124]. In addition, finite mutual coupling between antenna units causes the effective antenna impedance seen by a unit PA to vary in the different beam directions, often referred to as the mutual load pulling effect [125].…”

A Bi-Directional 300-GHz-Band Phased-Array Transceiver in 65-nm CMOS With Outphasing Transmitting Mode and LO Emission Cancellation

“…The bump position and PCB variations also cause phase offsets between the elements, so the output phase of each element must be adjusted manually. A calibration system can be considered as proposed by several works for lower frequency bands [69], [70], but it is beyond the scope of this work. The 3-D model of the CMOS pads and bumps is shown in Fig.…”

Review and comparison of different limited scan phased array antenna architectures

“…32 Moreover, as the phase shifting is performed in the RF domain, the phase shifter is designed to operate at RF (high) frequencies resulting in smaller on-chip area (due to smaller passive component size) and consequently reduced overall beamformer size. [36][37][38] The disadvantages of the RF path analog-beamforming topology are mainly NF and gain degradation. Since the phase shifters are placed in the signal path before combining them, the insertion loss and the NF of the phase shifters affect the overall performance of the beamformer.…”