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Terahertz channel performance in ULEO satellite-to-ground communications
Applied Optics
|March 17, 2026
Summary
Ultra-low Earth orbit (ULEO) terahertz (THz) satellite communications offer high bandwidth. Direct satellite-to-ground (S2G) links provide the best performance, outperforming relay and high-altitude base station architectures.
Area of Science:
- Space communication systems engineering
- Terahertz (THz) frequency applications
- Satellite network architectures
Background:
- Exponential growth in satellite data traffic necessitates communication systems beyond current microwave capacity.
- The terahertz (THz) band (0.1-10 THz) presents a solution with vast bandwidth and better weather resilience than optical systems.
- Ultra-low Earth orbit (ULEO) satellite deployments (<300 km) enhance THz communication potential.
Purpose of the Study:
- To conduct a comprehensive performance evaluation of ULEO-THz satellite-to-ground communication systems.
- To analyze and compare three distinct transmission architectures: direct satellite-to-ground (S2G), satellite-relay-ground (SRG), and satellite-to-high-altitude base station (S2H).
- To determine the optimal architecture for future high-capacity satellite data transmission.
Main Methods:
- Utilized altitude-resolved atmospheric propagation models validated with meteorological data from high-altitude stations.
- Incorporated frequency-dependent atmospheric absorption (ITU-R standards) and free-space path loss with curved atmospheric modeling.
- Analyzed channel path loss, available bandwidth, and bit error rate (BER) under AWGN and Weibull fading across multiple THz frequencies.
Main Results:
- Direct S2G transmission at lower THz frequencies demonstrated optimal practical performance and maximum available bandwidth under QPSK modulation.
- The SRG architecture suffered from prohibitive cumulative losses due to multiple hops.
- The S2H architecture was found impractical for long-haul links due to significant electro-optical conversion and fiber transmission losses.
Conclusions:
- Direct satellite-to-ground (S2G) links are the most promising architecture for ULEO-THz satellite communication systems.
- The findings provide critical insights for designing next-generation satellite communication networks to meet escalating data demands.
- Lower THz frequencies combined with S2G architecture offer a viable path for high-bandwidth, resilient satellite data transmission.
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