JERAJournal of Electronic Research and Application2208-35022208-3510Bio-Byword Scientific Publishing Pty. Ltd.10.26689/JERA.v10i9.15934ArticleBroadband Orthogonal Modulation Technology for Terahertz Inter‑satellite Communication of Low‑Earth‑Orbit Satellites from the Perspective of Software‑defined Radiohttps://artdesignp.com/journal/JERA/10/9/10.26689/JERA.v10i9.15934NieYongming,FengShixi,LiuHuifeng,YuBo20261092026-10-30Benefiting from the ultra‑wide continuous bandwidth of 0.1‑10 THz and strong beam directivity, the terahertz frequency band has become an important research direction for high‑speed inter‑satellite communication. Nevertheless, broadband orthogonal modulation faces great difficulties in bandwidth expansion, spectrum flatness maintenance, phase‑noise suppression, nonlinear compensation and other aspects. Based on the Software‑Defined Radio (SDR) architecture, this paper proposes a complete broadband orthogonal‑modulation scheme for the 220 GHz terahertz transmitting link of low‑earth‑orbit inter‑satellite communication. Research results show that within the GHz‑level bandwidth range, the proposed method can realize favorable spectrum constraint and sidelobe suppression; constellation stability meets the requirements of high‑order QAM modulation. Adaptive spectrum‑shaping compensation smooths the power spectrum and improves Error Vector Magnitude (EVM). The research outcomes provide systematic technical references for the engineering design of broadband reconfigurable modulation modules in transmitting systems for LEO inter‑satellite terahertz communication.Terahertz communication, Broadband orthogonal modulation, Software‑defined radio, Inter‑satellite link

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