Silver, Copper PCB Finishes Slash 5G Signal Loss Above 40 GHz

A new analysis from I-Connect007’s ‘Trouble in Your Tank’ series reveals that silver and copper solderable finishes significantly outperform nickel and palladium in reducing signal attenuation at frequencies above 40 GHz, a critical concern for 5G and 6G PCB designs.

The two-part article examines how surface finish selection directly impacts insertion loss in high-frequency circuits. As data rates climb into millimeter-wave bands, even minor conductivity differences cause measurable signal degradation. Testing shows that finishes with lower resistivity, especially immersion silver and copper, maintain signal integrity far better than nickel-based alternatives, which can suffer from increased losses due to skin effect at these frequencies.

The findings reinforce the need for PCB designers to treat finish selection as a first-order variable in 5G/6G hardware. While nickel-gold has been a workhorse in digital electronics, its magnetic properties introduce losses that become unacceptable above 28 GHz. For advanced applications like automotive radar, IoT backhaul, and next-gen base stations, specifying high-conductivity finishes is now essential to meeting link budget and thermal requirements.

For engineers sourcing high-frequency PCBs, finish selection is a key performance lever. LT CIRCUIT provides advanced PCB solutions with optimized surface finishes for 5G, automotive radar, and aerospace applications, ensuring minimal signal loss in mission-critical designs.