Multi-Waveguide Band Characterization of a 6G Terahertz Frontend

This paper presents a novel measurement setup for simultaneous characterization of a 300 GHz transceiver at IF and RF frequency reference planes where IF and RF lie in different waveguide bands. This setup is used for mapping time-domain signal quality measures, such as the error vector magnitude, to the nonlinear frequency-domain magnitude and phase characteristics. The measurement setup has to be carefully built with detailed configuration to enable vector averaging and source correction. Furthermore, a procedure for utilizing multiple frequency bands within a single configuration is delineated. The paper presents a detailed analysis of the signal quality within a H-band communication system, illustrating the calibrated input and the output of the transmitter, along with the received and down-converted signal at the receiver side. In order to facilitate characterization, 16-QAM and 64-QAM modulated signals with a 5 GBd symbol rate are employed. The input signal was pre-distorted achieving an EVM of 0.8% in WR-10 band, where the output could be measured to 4% and 4.8% at the Tx output in WR-3.4 band and at the Rx output in WR-10 band, respectively.