Reconfigurable K-Band MIMO Transmission With On-Board Vector Calibration

This paper presents a reconfigurable multi-input and multi-output amplifier architecture with on-board multiport vector calibration (MVC) for flexible multi-channel transmission in K-band. The proposed architecture controls phases of K-band transmission path to generate a diversity of source-to-target channel power assignment. In addition, the proposed calibration circuitry detects relative amplitude and phase of each transmission path and ensures high isolation at each output port. The proposed architecture consists of waveguide hybrid matrices, amplifier modules, including phase shifter, attenuator and 0°/180° phase inverter monolithic microwave integrated circuits (MMICs), and a MVC block. The MVC is configured with a modulator, two QPSK demodulator MMICs, a digital signal processing board, and 16 digital-to-analog converter units. For the verification of K-band applications, $4\times4$ multi-channel front end was implemented and showed reconfigurable performance as well as stable port-to-port isolation characteristics better than 26 dB from 19.5 to 22.5 GHz.