As the global Low-Altitude Economy (LAE) enters a phase of substantive explosion, Unmanned Aerial Vehicles (UAVs) are transitioning from consumer-grade entertainment to complex industrial-grade productivity tools. In this transformation, communication link stability and environmental sensing precision have become the core bottlenecks hindering large-scale industrialization. From the perspective of an Antenna Factory, this article provides an in-depth exploration of how 5G-Advanced (5G-A) Public Network Direct-to-Cell technology and Integrated Sensing and Communication (ISAC) are revolutionizing RF front-ends to build a secure and efficient low-altitude digital airspace.
I. Strategic Significance of the Low-Altitude Economy and Physical RF Challenges
The Low-Altitude Economy refers to a comprehensive economic form driven by manned and unmanned aerial vehicles, encompassing passenger transport, cargo delivery, and other flight operations. According to 2026 industry forecasts, the global LAE output value is expected to exceed one trillion dollars.
1. Limitations of Traditional Communication Links
Over the past decade, UAVs have primarily relied on traditional 2.4GHz and 5.8GHz ISM bands for Point-to-Point (P2P) communication. However, in the context of the LAE explosion, this model faces three major challenges:
Line-of-Sight (LoS) Restrictions: Traditional dedicated links struggle to support Beyond Visual Line of Sight (BVLOS) flights between urban clusters.
Spectrum Congestion: As UAV density increases, co-channel interference leads to frequent link drops.
Security Risks: The lack of a unified management platform makes it difficult for regulatory authorities to obtain real-time flight status data for massive UAV fleets.
2. The Mission of the Antenna Factory: From "Component Supplier" to "Solution Provider"
Modern antenna factories are no longer mere hardware processors. To meet LAE demands, leading manufacturers are deeply involved in Physical Layer (PHY) protocol R&D, utilizing customized onboard antenna designs to optimize the radiation characteristics of radio waves at altitudes of 300 to 1,000 meters (i.e., 3D coverage optimization).
II. Public Network Direct-to-Cell: How Antenna Factories Reshape UAV Communication Backbones
Public Network Direct-to-Cell allows UAVs to connect directly to the internet via mobile communication networks (such as 5G-A or 6G), enabling long-distance, low-latency interaction with ground control centers.
1. High-Gain Arrays and Polarization Optimization
In low-altitude flight, UAV airframe oscillations and attitude adjustments cause signal polarization mismatch.
Circular Polarization (CP) Applications: Professional antenna factories are mass-producing quadrifilar helix antennas or circular polarization arrays. These designs effectively combat ionospheric disturbance and ground multi-path reflection, ensuring signal stability during rotation.
High-Gain Beamforming: Addressing limited onboard space, antenna factories utilize low-loss materials such as LCP (Liquid Crystal Polymer) or MPI (Modified Polyimide) to fabricate miniaturized high-gain antennas, maintaining high-quality link budgets even at the cell edge.
2. Multi-Band Integration and SWaP-C Design
UAVs are extremely sensitive to Size, Weight, and Power (SWaP).
All-in-One Integration: Factories integrate 5G, GNSS (Global Navigation Satellite System), video transmission, and telemetry antennas into a single housing, using RF isolation technology to reduce mutual interference.
Advanced Material Application: Using Laser Direct Structuring (LDS), antenna circuits are etched directly onto the inner walls of the UAV chassis, achieving "structural integration" that reduces weight while enhancing aerodynamic performance.
III. Integrated Sensing and Communication (ISAC): The Ultimate Form of Antenna Evolution
ISAC is the "crown jewel" of 2026 RF technology. It breaks the boundary between communication and sensing, giving antennas "radar eyes."
1. Technical Core: Communication Waveforms for Radar Functions
In an ISAC architecture, the OFDM (Orthogonal Frequency Division Multiplexing) signals transmitted by the antenna carry data and are reflected by surrounding objects (buildings, other UAVs, utility poles).
Echo Resolution: The onboard system uses sophisticated algorithms to analyze Doppler shift and Time of Flight (ToF) of the echo, enabling environmental modeling without additional hardware.
Performance Enhancement: According to antenna factory test reports, ISAC-integrated antennas can detect dynamic obstacles within 500 meters with centimeter-level positioning accuracy.
2. The Technological "Moat" of Antenna Factories in ISAC
Meeting ISAC specifications is notoriously demanding:
Phase Consistency: Detection requires extreme phase precision. Factories must use high-precision automated calibration lines to ensure the initial phase deviation of each element in a phased array is minimized.
Broadband Beam Dynamic Tuning: Detection and communication often occupy different spectral widths. Factories are developing reconfigurable antenna technologies that dynamically adjust radiation characteristics based on real-time needs, prioritizing communication or enhancing sensing accuracy.
IV. Industry Perspective: Why Professional Antenna Factories are a Core Competency
For LAE enterprises (such as SF Express, Meituan, or DJI), antennas are not generic commodities but strategic assets requiring deep customization.
1. Rigorous Airworthiness Testing
Professional antenna factories possess laboratories compliant with international civil aviation standards, capable of performing:
Extreme Temperature Cycling: Simulating UAV performance in high-altitude cold and high-heat motor environments.
Salt Spray and Fungus Resistance: Addressing operational needs in coastal and tropical regions.
EMC (Electromagnetic Compatibility) Scanning: Ensuring antenna radiation does not interfere with onboard flight control systems.
2. Commercialization of AiP (Antenna in Package)
With the introduction of millimeter-wave (mmWave) bands, feeder loss becomes critical.
Packaging as the Antenna: Top-tier factories integrate antenna elements directly into the RF chip package (AiP). This design virtually eliminates connector loss, significantly improving signal transmission efficiency.
IV. Industry Perspective: Why Professional Antenna Factories are a Core Competency
For LAE enterprises (such as SF Express, Meituan, or DJI), antennas are not generic commodities but strategic assets requiring deep customization.
1. Rigorous Airworthiness Testing
Professional antenna factories possess laboratories compliant with international civil aviation standards, capable of performing:
Extreme Temperature Cycling: Simulating UAV performance in high-altitude cold and high-heat motor environments.
Salt Spray and Fungus Resistance: Addressing operational needs in coastal and tropical regions.
EMC (Electromagnetic Compatibility) Scanning: Ensuring antenna radiation does not interfere with onboard flight control systems.
2. Commercialization of AiP (Antenna in Package)
With the introduction of millimeter-wave (mmWave) bands, feeder loss becomes critical.
Packaging as the Antenna: Top-tier factories integrate antenna elements directly into the RF chip package (AiP). This design virtually eliminates connector loss, significantly improving signal transmission efficiency.
VI. Conclusion: Antennas—The Bridge Connecting Low-Altitude to the Future
The prosperity of the Low-Altitude Economy is essentially a fusion of digital airspace management and aircraft intelligence. By continuously breaking through Physical Layer limitations, Antenna Factories provide UAVs with a robust "neural network" and sensitive "environmental perception." In the landscape of 2026, solutions featuring Public Network Direct-to-Cell and ISAC capabilities will undoubtedly hold the high ground in technical competition.
