When sourcing 5G panel antennas, you must prioritize Frequency Range (Sub-6GHz vs. mmWave) to ensure compatibility with local carriers. Key metrics include Gain (measured in dBi), where a higher gain indicates better directional signal strength, and VSWR (Voltage Standing Wave Ratio), which should ideally be less than 1.5 to minimize signal reflection and power loss. Additionally, check for MIMO (Multiple Input Multiple Output) support, typically 2x2 or 4x4, to enhance data throughput and network stability.