In RF and microwave systems, the power splitter is a core passive component responsible for dividing an input signal into multiple outputs with minimal loss and perfect impedance balance.
From cellular base stations to satellite networks and RF test systems, the power splitter ensures signal integrity across transmission paths.

1. Basic Principle of Power Splitters

A power splitter divides an input signal evenly into two or more outputs while maintaining amplitude, phase, and impedance balance.

In ideal conditions, each output receives equal power $P_{out} = P_{in}/N$, but real-world designs face insertion loss caused by conductor resistance, dielectric losses, and imperfect matching.

Key performance metrics include:

• Insertion Loss (IL)

• Isolation between outputs

• VSWR (impedance matching)

• Amplitude and phase balance

• Low PIM (Passive Intermodulation) performance

2. Types of Power Splitters and Structural Features

1. Microstrip Power Splitter

The microstrip power splitter uses printed circuit transmission lines on dielectric substrates. It is lightweight, easy to integrate, and widely used in indoor DAS and small-cell systems.

Features:

• Compact and low-cost structure

• Suitable for broadband applications (600–6000 MHz)

• Easy PCB fabrication and mass production

• Low PIM achievable with optimized conductor layout and grounding

Applications:
DAS systems, small-cell coverage, RF test platforms.

2. Cavity Power Splitter

The cavity power splitter is a precision-machined metal component that uses resonant cavities and coaxial lines for high-power and high-frequency operation.

Features:

• Excellent power handling capability

• Low insertion loss and high isolation

• Strong mechanical reliability and environmental resistance

• Ultra-Low PIM performance due to solid metal shielding and fewer junctions

Applications:
Base station feeders, outdoor networks, high-power satellite or radar systems.

3. Stripline Power Splitter

The stripline power splitter employs a symmetrical transmission line structure embedded within a dielectric layer, offering superior phase and amplitude balance across wide frequency ranges.

Features:

• Excellent amplitude and phase consistency

• Compact multilayer structure suitable for integration

• Low return loss and stable impedance characteristics

• Low PIM through optimized multilayer metallization and bonding process

Applications:
5G MIMO antennas, multi-channel signal distribution, phased-array networks.

3. Key Design Parameters and Optimization

Design optimization tools: Keysight ADS, Ansys HFSS, CST Microwave Studio — used for tuning line width, dielectric constant, cavity geometry, and connector interfaces.

4. Importance of Low PIM in Splitter Design

In modern 5G networks, low PIM performance directly affects system linearity and data throughput.
Minor imperfections — such as surface oxidation, loose connectors, or uneven contact — can generate intermodulation products, degrading SINR and EVM.

Engineering solutions for Low PIM:

• High-conductivity plating (silver or gold)

• Smooth mechanical joints and uniform torque control

• Fully welded or soldered internal structures

• PIM-optimized connectors (4.3-10, N-F, DIN-F)

5. Typical Applications of Power Splitters

1. 5G and 4G Base Stations – Multi-antenna power distribution and feeder networks.

2. DAS (Distributed Antenna Systems) – Signal splitting for indoor coverage.

3. Laboratory Testing – Synchronizing multiple RF outputs.

4. Satellite and Defense Systems – Power balancing in high-frequency payload chains.

6. Future Trends: Toward Integration and Intelligence

As communication systems evolve, power splitter technology continues to advance toward:

• Ultra-Wideband Design (600–6000 MHz)

• Integrated Multi-Port Modules

• High-Power, Low-Loss Cavity Materials

• Intelligent Power Control through tunable or MEMS-based architectures