en.Wedoany.com Reported - The commercialization of direct-to-cell satellite connectivity for low Earth orbit (LEO) is accelerating. Dual-mode terminals represented by the Huawei Mate60 have entered mass sales, but they currently connect to geostationary orbit (GEO) satellites 36,000 kilometers above Earth, providing only emergency communication. LEO direct-to-cell satellite constellations with true global coverage potential, such as Starlink Direct to Cell, AST SpaceMobile, and China's rapidly deploying GW, Qianfan, and Honghu-3 constellations, are at a critical juncture of technical verification and large-scale networking, with commercial services expected to launch between 2025 and 2026.
Compared to GEO satellites, LEO satellites offer significant advantages for direct-to-cell services. The 3GPP Release 17 standard established the NTN non-terrestrial network architecture, with the S-band becoming the core downlink frequency band for direct-to-cell satellite connectivity. A single LEO satellite can achieve a coverage radius of 800 to 1,500 kilometers, but the coverage area is approximately 500 square kilometers, requiring large-scale networking. Full digital phased array technology enables precise multi-beam pointing, supporting stable connections for different users within the coverage area. According to public data, China's GW, Qianfan, and Honghu-3 constellations plan a total of over 40,000 satellites. Over the next decade, China's domestic demand for LEO satellite payload PAs is estimated at 30 to 40 million units, with a market size reaching tens of billions of yuan.
Huatai Electronics noted that only three GEO satellites are needed for global coverage, but a single LEO satellite has limited coverage, necessitating large-scale networking. Starlink has already deployed nearly 10,000 LEO satellites, with a long-term plan of 40,000; China's domestic constellation plans each approach 15,000 satellites. The number of RF channels and PA requirements for LEO satellites far exceed those of GEO satellites, making this the core incremental market for satellite internet. LEO satellites orbit at altitudes of only 600 to 1,000 kilometers, with latency of just tens of milliseconds and low signal loss, supporting high-data-rate services like HD video and streaming, offering a user experience close to terrestrial 5G.
Regarding why the industry initially developed GEO satellite direct-to-cell services, Huatai Electronics explained that the large-scale deployment of LEO satellites depends on the maturity of phased array technology. Early phased array technology was underdeveloped, and GEO satellites used traditional architectures with relatively simpler technology. Direct-to-cell connectivity requires the S-band, necessitating ultra-large phased arrays on the satellite side, a technology that only matured with the evolution of active phased arrays. Business logic and maturity are equally critical; SpaceX's rocket reusability has significantly reduced launch costs, making large-scale networking feasible.
LEO orbit and spectrum resources follow a "first-come, first-served" principle. Huatai Electronics pointed out that currently, only China and the United States are major players. China must accelerate its launch pace while reducing launch and recovery costs. LEO satellites experience an annual attrition rate of about 10% to 15%, requiring continuous launches to maintain constellation stability and network coverage.
In satellite communication payloads, the power amplifier module is the core component determining downlink performance. Its performance directly impacts coverage capability, signal quality, and energy efficiency and weight reduction. Currently, major global RF semiconductor manufacturers are trending toward higher frequencies in their power amplifier layouts for LEO satellite communications, with substantial resources directed to the Ku/Ka bands. However, spaceborne S-band power amplifier modules specifically designed for direct-to-cell satellite downlinks are virtually absent from the global market.
Huatai Electronics' analysis indicates that the Ku/Ka bands are used for LEO broadband internet, offering advantages in large bandwidth and high data rates, making them the core frequency bands for Starlink's early commercialization. The S-band has lower frequency, stronger penetration, stable signals, and lower requirements for terminal antennas. The two are complementary. Several domestic LEO constellation projects in China have attempted to repurpose terrestrial cellular general-purpose power amplifier chips, but this approach suffers from fundamental shortcomings, including power bottlenecks, efficiency bottlenecks, and reliability bottlenecks.
Addressing this technology and market gap, Huatai Electronics has launched its first dedicated S-band GaN payload PAM product. This product covers the frequency range of 2.17 to 2.2 GHz (3GPP n256), with a back-off efficiency greater than 50%, gain greater than 30 dB, and EVM less than 5%. Huatai Electronics stated that the product's back-off efficiency of 50% is industry-leading, significantly reducing satellite power consumption and heat dissipation burden; the power level is enhanced, outperforming solutions adapted from terrestrial small stations. The chip size is only 7×7 mm, integrating 50Ω input and output matching, meeting the volume and weight constraints of spaceborne payloads. The product uses GaN technology and has passed space-grade verification tests including radiation resistance, thermal vacuum, vibration, and temperature cycling. With excellent open-loop linearity, it ensures signal fidelity even without digital pre-distortion (DPD).
Focusing on platform-based rapid iteration capabilities, Huatai Electronics' first product is based on a unified platform, enabling the rapid derivation of products with different frequency bands and power levels within 6 to 9 months. Huatai Electronics emphasized that while currently focusing on the S-band, China's domestic satellite internet is in its early stages, and the spectrum of various operators has not yet been unified. The company has established a unified PA technology platform to quickly respond to diverse customer needs. At the industry engagement level, Huatai Electronics directly interfaces with leading payload suppliers. The first product has completed joint testing with key customers, with samples to be provided in the second quarter of 2026 and mass production shipments in the fourth quarter.
