I. Core Technical Parameters for IBS/DAS Compatibility

　　Frequency Coverage Supported by Multiple Services

　　IBS/DAS systems need to cover multiple operators and multiple standards signals; therefore, the frequency range must cover 698MHz-6GHz (fully covering 2G/3G/4G/5G) and be compatible with 2.4GHz/5.8GHz Wi-Fi. High-performance models achieve seamless coverage, avoiding signal loss at critical transition points (e.g., the 2.6GHz 5G band and the 1.8GHz 4G band)—a key requirement for multi-service convergence in locations such as shopping malls, subways, and office buildings.

　　Low Insertion Loss and Loss Flatness (Core Indicators)

　　Insertion Loss: ≤13.5dB (including 12dB theoretical 16-way distribution loss)—lower than satellite/5G macro base station splitters (typically ≤14dB/15dB). This reduces signal attenuation in DAS cascaded networks, thereby minimizing the number of subsequent amplifiers and reducing system noise.

　　Loss Flatness: ≤±0.3dB in the 698MHz-6GHz band. IBS/DAS carries signals at different frequencies (e.g., 700MHz 5G, 2.1GHz 3G). Uneven signal loss can lead to inconsistent signal strength between different frequency bands, thus affecting user experience (e.g., slow 5G speeds but normal 4G speeds).

　　VSWR: ≤1.3:1 (698MHz-6GHz) – More stringent than typical indoor splitters (≤1.5:1) to avoid signal reflections in multi-port DAS connections, thus preventing interference with adjacent antenna ports.

　　Isolation: ≥22dB between all ports (not just adjacent ports) – Crucial for multi-operator shared IBS/DAS scenarios (e.g., joint DAS deployment by China Mobile, China Unicom, and China Telecom), preventing crosstalk between different operator signals.

　　Power Capacity: 20-30W continuous power – Matches the output power of the DAS remote radio unit (RRU, typically 10-25W) to avoid overload damage in high-traffic scenarios (e.g., sports stadium events).

　　Indoor Deployment Environmental and Structural Adaptability

　　Operating Temperature: -20℃ to +60℃ – Suitable for indoor environments with minimal temperature fluctuations (e.g., shopping mall ceilings, subway tunnel equipment cabinets) (narrower range than satellite outdoor splitters: -50℃ to +70℃).

　　Protection Rating: IP54 – Dust and splash resistant, meeting the requirements of semi-outdoor DAS nodes (e.g., rooftop units) while avoiding the high cost of IP66 (IP66 is not required for fully indoor use).

　　Interface Type: N-type female connector (for DAS backbone connections, high reliability) or SMA-J (for compact indoor antenna ports); all interfaces have a 50Ω characteristic impedance (standard for IBS/DAS RF links).

　　Dimensions and Installation: Compact design (≤200×150×50mm), wall-mounted or rack-mounted (1U half-height) options available – suitable for limited installation space in IBS/DAS (e.g., ceiling cavities, small equipment cabinets).

　　II. IBS/DAS Low Insertion Loss Core Technologies

　　Low-Loss Transmission Line and Dielectric Design

　　Conductor Material: The microstrip line uses oxygen-free copper (OFC) with a conductivity ≥99.95%, effectively reducing conductor loss (conductor loss is the main source of insertion loss in low-frequency bands such as 698MHz).

　　Dielectric Substrate: Ceramic-filled polytetrafluoroethylene (PTFE) (dielectric constant εr=2.6, tanδ≤0.0005 at 6GHz) is used, with lower dielectric loss than pure PTFE, ensuring low attenuation even in the 5G high-frequency band (5-6GHz).

　　Transmission Line Optimization: Broadband impedance matching (multi-segment Chebyshev matching network) is used to smooth the insertion loss in the 698MHz-6GHz band, eliminating loss spikes at band edges (e.g., the 698MHz-700MHz transition section).

　　High-Efficiency Power Distribution Topology

　　Optimized Wilkinson power divider with a star-shaped multi-port layout: Reduces the number of cascading stages (traditional 16-channel dividers use 4 cascades, while this design uses 2 parallel stages), thereby reducing cumulative insertion loss by 0.5-1dB.

　　Integrated low-loss matching resistors (metal film resistors with a resistance tolerance of ±1%, rated power 1W): Avoids losses caused by parasitic resistance, ensuring stable performance even under prolonged high-power operation.

　　Optimized Cavity and Shielding

　　One-piece die-cast aluminum alloy cavity: Eliminates gaps (an additional source of loss in the assembled cavity), reduces electromagnetic leakage, while the smooth inner wall (Ra≤0.8μm) minimizes signal scattering loss.

　　3μm thick gold plating on the inner cavity: Gold has lower skin effect losses than silver (especially in the ≥3GHz high-frequency band) and better corrosion resistance, ensuring long-term low-loss performance in humid indoor environments (such as underground shopping malls).

　　III. Key Considerations for IBS/DAS Scenario Selection

　　Scenario-Specific Adaptation

　　Large Commercial Complexes (Shopping Malls/Center Stores): Prioritize low-loss flatness (≤±0.3dB) and multi-band coverage (698MHz-6GHz) to simultaneously support 5G, 4G, and Wi-Fi, ensuring consistent signal quality across different store areas.

　　Subway Tunnels/Subway Stations: Select vibration-resistant design (compliant with GB/T 2423.10-2019 standard, 10-500Hz vibration test).Compact size (≤180×120×40mm) – can be installed in narrow tunnel equipment cabinets and withstand vibrations caused by trains.

　　Office Buildings/Multi-tenant Distributed Antenna Systems (DAS): Emphasis on high port isolation (≥25dB) and multi-carrier compatibility – prevents interference between private networks of different companies (e.g., corporate Wi-Fi) and public mobile signals.

　　Sports Stadiums/Exhibition Halls (High-traffic Scenarios): Select high power capacity (30W) and low temperature rise (≤30℃ at full power) – avoid overheating during peak user periods (e.g., concerts with over 10,000 users).

　　Synergy with DAS System Architecture

　　Cascaded DAS Networks: For large-scale IBS (e.g., airport terminals with more than 100 antenna points), select splitters with low insertion loss (≤13dB) to reduce the need for intermediate amplifiers (each amplifier adds 0.2-0.5dB to the noise figure, thus reducing the signal-to-noise ratio).

　　Distributed RRU + Splitter Integration: Matches the splitter's input impedance to the DAS RRU's input impedance (typically 50Ω, VSWR ≤ 1.2:1), ensuring efficient signal transmission and preventing RRU protection mechanism shutdown due to reflections.

　　Passive DAS Compatibility: For passive IBS (without active amplifiers), the splitter's insertion loss must be ≤ 13dB to ensure the final antenna output power meets minimum requirements (≥ -10dBm for 5G signals according to YD/T 2721-2014).

　　Telecommunications Standard Compliance

　　Must comply with specific IBS/DAS industry specifications:

　　YD/T 2721-2014 "Technical Requirements for Indoor Distributed Antenna Systems in Mobile Communication Networks" (Low Insertion Loss, Multi-Band Compatibility).

　　EN 301 489-1/3 (Electromagnetic Compatibility Immunity of Mobile Communication Equipment, Avoiding Interference with DAS Baseband Units).

　　RoHS 2.0 (Restriction of Hazardous Substances) – a necessary condition for indoor use (e.g., kindergartens, hospitals) to ensure environmental safety.

　　IV. Typical IBS/DAS Application Scenarios

　　Shopping Mall DAS Deployment

　　The shopping mall's central equipment room uses 16 low-loss splitters to distribute 5G (700MHz/2.6GHz/3.5GHz), 4G (1.8GHz/2.1GHz), and Wi-Fi (2.4GHz/5.8GHz) signals from three operators' RRUs to 16 passive antennas (installed in individual shops and corridors). Low insertion loss (≤13.5dB) ensures that the output power of each antenna is ≥-8dBm, meeting the requirement of "5G download speed ≥300Mbps".

　　Subway Tunnel IBS

　　In the subway line, the splitter is installed in equipment boxes on the tunnel side (one every 500 meters): it distributes 5G (2.6GHz) and 4G (1.8GHz) signals from the main tunnel RRU to 16 small antennas (mounted on the tunnel wall). Its seismic-resistant design and compact size (180×120×40mm) allow it to operate stably under vibrations caused by trains, while low-loss flatness (≤±0.3dB) ensures consistent signal coverage between adjacent antenna points.

　　Office Building Multi-Carrier DAS

　　For a 50-story office building, the splitter is deployed in the low-voltage shaft on each floor: it shares a single DAS network for 3 carriers and distributes their signals to 16 antennas (one per office area). High port isolation (≥25dB) prevents crosstalk between carrier signals, while low insertion loss reduces the number of ground amplifiers from 3 (traditional splitters) to 1, thus lowering system cost and noise.

　　Temporary DAS for Stadiums (Event-Specific)

　　During sporting events, this splitter is used in temporary outdoor racks: it distributes high-power (25W) 5G signals from mobile RRUs to 16 temporary antennas (deployed around the stadium stands). A 30W power capacity and low temperature rise ensure stable operation for over 8 hours (event duration), while an IP54 protection rating withstands light outdoor rain and meets the connectivity needs of "100,000+ concurrent users".

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