A combiner is a key communication device that merges multiple signals into one transmission medium, widely used in wireless and optical fiber communication. Its core function is efficient signal integration via multiplexing, such as combining different frequency signals for transmission through the same antenna or fiber, reducing system complexity and costs.
Future Challenges and Trends
1. Multi-Band and Ultra-Wideband Breakthroughs
5G/6G demands wider frequency support: 5G requires 1695-4200MHz coverage, with 6G possibly extending to millimeter waves. Traditional combiners, with many discrete components and large sizes, struggle to meet multi-band needs. Issues like signal interference, insertion loss control, and phase consistency remain challenging.
2. Miniaturization vs. High-Power Handling
5G base stations and smart devices impose strict size and weight requirements on combiners. Miniaturization often causes heat dissipation problems, as high-power operation (e.g., 300W) may lead to structural deformation. Balancing smaller size with higher power capacity remains a hurdle.
3. Software Definition and Dynamic Spectrum Adaptation
With Software-Defined Radio (SDR) popularization, combiners need dynamic spectrum sharing and flexible configuration. For example, public security trunking systems use SDR to set frequencies via software, reducing hardware reliance. Challenges include rapid response to frequency adjustments, real-time multi-system signal processing/interference suppression, and coordination with BBU+RRU architectures.
4. Low Insertion Loss and High Isolation Bottlenecks
Insertion loss and isolation directly impact system efficiency. Multi-band combining can cause crosstalk, reducing isolation. Solutions may involve new materials (e.g., gallium nitride) or feedforward cancellation to tackle intermodulation interference.
5. Localization and Supply Chain Control
Foreign manufacturers long monopolized high-performance combiners. Domestic breakthroughs (e.g., SPD-based quadplexers) exist, but core technologies (precision filters, advanced processes) need advancement. Strengthening industry-academia-research collaboration and industrial chain synergy is vital for supply chain security.
6. Green Communication and Energy Efficiency
Network expansion makes combiner energy efficiency critical. Thermal management of high-power units affects both performance and energy use. ANSYS simulations optimize heat dissipation, while low-loss materials (e.g., ceramic substrates) boost efficiency. AI-based dynamic parameter adjustment could balance efficiency and performance.
Combiners will develop around "multi-frequency, high efficiency, intelligence, greenness," requiring progress in materials, structures, and algorithms. Software-defined features and dynamic spectrum management are key for 6G. With domestic industrial chain improvements, combiners have bright prospects in 5G/6G, IoT, and connected cars, but must address technical complexity and rapid market changes.