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Propagation Measurement System at 220 GHz

In this paper, a long-distance propagation measurement system at 220 GHz is proposed. In order to tackle the challenge of long-distance (i.e., 2.5 km) terahertz propagation, TX/RX RF -fronts, high-gain antennas, and intermediate-frequency (IF)/ digital signal processing platform are all deliberately designed and utilized to achieve sufficient link-budget margin. As compared with other existing above-100 GHz measurement solutions, the proposed system can complete the propagation measurement with longer distance. To validate the proposed system, related measurements are carried out to confirm the performance, including the test of the transmitted power, noise figure/gain of RX link, etc. To measure the propagation loss for the long-distance scenario, out-door experiments are performed, whose results is compared with the predicted results based on international telecommunication union (ITU) model. Loss gap is observed between these two results. Therefore, in order to obtain accurate prediction on the terahertz-wave propagation loss, it is highly necessary to make revision on the traditional ITU model. The proposed measurement system would make contributions for such revision.