I. Technical Positioning and Core Functions

　　In 5G base station systems, the microwave power divider is a core passive device connecting the Radio Frequency Unit (RRU), Massive MIMO antenna array, and T/R modules. It directly impacts network capacity, coverage, and user experience. Its core functions include:

　　Massive MIMO Signal Distribution: Distributing the RF signal output from the RRU evenly to 16/32/64/128 T/R modules (adapting to different sizes of Massive MIMO arrays), and working with phase shifters to achieve beamforming, precisely focusing signal energy to the user terminal, improving spectral efficiency by 3-5 times;

　　Transmit/Receive Mode Adaptation: In TDD (Time Division Duplex) systems, through collaboration with switching circuits, it dynamically switches between transmit signal distribution and receive signal synthesis, adapting to uplink/downlink time slot configurations with 2.5ms/5ms dual-cycle frame structures;

　　Multi-Band Compatibility: Supports… Signal allocation across Sub-6GHz (3.5GHz, 4.9GHz) and millimeter-wave (28GHz, 39GHz) bands is required, with some scenarios needing to be compatible with 4G LTE bands (1.8GHz, 2.6GHz) to meet the needs of smooth network evolution.

　　Its operating frequency bands need to cover mainstream 5G bands (Sub-6GHz: 3.3-5.0GHz; millimeter-wave: 24.25-52.6GHz), adapting to different deployment scenarios such as macro base stations, micro base stations, and pico base stations.

　　II. Key Requirements for 5G Base Station Adaptation High Channel Amplitude and Phase Consistency Massive MIMO beamforming is sensitive to channel consistency. The amplitude imbalance at each output port of the power divider must be ≤0.2dB, and the phase imbalance ≤5° (full band). Otherwise, it will cause beam pointing deviation (e.g., a 3° phase deviation can cause a 0.5° beam shift), reducing user signal strength. For example, in a 3.5GHz macro base station, the consistency of the 64-channel power divider needs to be controlled within 0.15dB/3° to ensure an edge user rate increase of over 20%.

　　Balancing Wide Bandwidth and Low Insertion Loss

　　To adapt to multi-band and high bandwidth requirements (Sub-6GHz single-carrier bandwidth up to 100MHz, millimeter wave up to 400MHz), the relative bandwidth of the power divider needs to be ≥30%, while the insertion loss needs to be strictly controlled: ≤0.3dB for Sub-6GHz band and ≤0.5dB for millimeter wave band. Low-loss design can reduce the RRU transmit power requirement; for example, for every 0.1dB reduction in insertion loss, the coverage radius of the macro base station can increase by 50 meters.

　　Adapting to Continuous Wave Power Characteristics

　　5G base stations use continuous wave transmission mode, and the power divider needs to withstand the average power load: macro base station power divider ≥20W (with a 50W-class GaN power amplifier), micro base station power divider ≥5W, and there is no risk of thermal failure during long-term operation. For example, a 4.9GHz macro base station power divider needs to support 25W continuous power and a VSWR ≤ 1.2.

　　High integration and controllable cost: Macro base station antenna arrays need to integrate dozens to hundreds of power dividers, with a single channel volume ≤ 2cm³, using LTCC or PCB integration processes to achieve miniaturization; simultaneously, performance and cost must be balanced, with FR-4 substrates (tanδ ≤ 0.02) preferred for Sub-6GHz scenarios, and Rogers RT/duroid 5880 (tanδ ≤ 0.0009) used for high-frequency bands.

　　Strong anti-interference and environmental adaptability: To cope with interference from multiple operators coexisting on adjacent channels (such as China Telecom/China Unicom and China Mobile/China Broadcasting Network deployments on the 3.5GHz band), the power divider port isolation must be ≥25dB, and out-of-band rejection ≥40dBc (at a 5MHz deviation from the center frequency); environmental adaptability must meet the following requirements: macro base stations -40℃ to +65℃ wide temperature range, micro base stations IP65 protection rating, and MTBF ≥10⁶ hours.

　　III. Core Design Technologies and Optimization Directions

　　Topology Selection

　　Massive MIMO Scenarios: A tree-cascaded Wilkinson power divider is used, with 3-4 sections of impedance transformation network to broaden bandwidth. Symmetrical layout reduces consistency errors, adapting to 64/128-channel arrays. For example, a 3.5GHz 64-channel power divider achieves isolation ≥28dB.

　　Multi-Band Compatible Scenarios: A dual-band power divider structure is used, with stepped impedance resonators loaded on branch lines to achieve dual-band coverage of 3.5GHz and 4.9GHz, with relative bandwidth ≥25% for both bands.

　　Micro Base Station Scenarios: An LTCC integrated 2×4 power divider is used, compressing the size to 3mm×6mm×1mm, and AIP (antenna in-package) technology is used to reduce link loss.

　　Materials and Process Optimization

　　Substrate Selection: FR-4 reinforced material (εr=4.4) is used for Sub-6GHz to balance cost and loss; sapphire substrate (εr=11.7) is used for millimeter-wave to improve stability.

　　Metalworking: Electroplated silver layer (thickness ≥18μm) is used to reduce conductor loss; gold plating layer (thickness ≥3μm) is used for shipborne macro base stations to enhance salt spray resistance.

　　Integration Solution: Power dividers, duplexers, and filters are integrated into PAMiD (Power Amplifier Modules), such as the Skyworks SKY5 series modules which integrate a four-channel power divider and duplexer, reducing the base station front-end size by 30%.

　　Performance Enhancement Design

　　Conformity Compensation: Fine-tuning capacitors and microstrip delay lines are introduced into the branch paths, achieving phase deviation ≤2° and amplitude deviation ≤0.1dB through laser fine-tuning;

　　Interference Suppression: An integrated cavity filter at the input port improves out-of-band rejection to 50dBc, mitigating cross-interference between the 3.5GHz and 4.9GHz bands;

　　Thermal Management: The macro base station power divider uses an aluminum substrate (thermal conductivity ≥200W/(m・K)), combined with antenna array heat dissipation channels, controlling the operating temperature to ≤60℃.

　　IV. Typical Application Scenarios

　　Sub-6GHz Macro Base Station Massive MIMO System

　　In a 3.5GHz macro base station (such as Huawei AAU5613), a 128-channel tree-cascaded power divider is used to distribute a 40W RRU signal to 128 T/R modules. Amplitude consistency ≤0.12dB, phase consistency ≤2.5°, and beamforming enable simultaneous access for 16 users, achieving a single-sector throughput of 20Gbps and a coverage radius ≥500 meters.

　　Urban Micro Base Station Coverage Scenarios

　　The Xiamen Luling Road streetlight pole micro base station uses an LTCC integrated 2×4 power divider (covering the 3.5GHz band), with a size of only 4mm×8mm×1mm and a weight ≤0.5g. Combined with 64 antenna elements, it achieves precise coverage within a 100-meter radius, solving signal blind spots in office buildings and roads, with user downlink speeds reaching 1Gbps.

　　High-Density Coverage with Millimeter-Wave Small Cells

　　In 28GHz millimeter-wave small cells (such as the Ericsson MMH6000), an 8-channel waveguide power divider is used, with insertion loss ≤0.4dB and relative bandwidth of 33% (26-34GHz). Combined with a phased array antenna, it can achieve simultaneous scanning of 8 beams, supporting the capacity requirement of 500Mbps per square meter in dense areas such as shopping malls, with user latency ≤1ms.

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