50 GHz Four-Port Coupling-Reduced Probe Card Utilizing Pogo Pins Housed in Custom Metallic Socket.

Area of Science:

• Electrical Engineering
• Materials Science
• Radio Frequency (RF) Engineering

Background:

• Signal integrity is critical in multi-port RF systems, where crosstalk and leakage can degrade performance.
• Conventional dielectric probe cards often suffer from signal coupling issues, limiting their effectiveness at higher frequencies.
• Minimizing signal loss and maximizing isolation are key challenges in designing advanced RF probe solutions.

Purpose of the Study:

• To propose and validate a metallic pogo-pin probe card design engineered to eliminate signal leakage and coupling loss.
• To demonstrate superior performance compared to traditional dielectric-based probe cards in multi-port RF environments.
• To enable reliable, high-frequency RF signal delivery to integrated circuits.

Main Methods:

• A metallic pogo-pin socket design incorporating a metal wall structure between adjacent pins was developed.
• A prototype probe card was fabricated using the proposed design.
• Performance was evaluated through measurements on a test through line and for RF signal delivery to a 5G circuit.

Main Results:

• The metallic wall effectively minimized coupled power, achieving low-loss transmission of -2.14 dB at 50 GHz.
• The probe card demonstrated a low coupling performance below -15 dB in the millimeter-wave band, despite minor leakage from dielectric spacers.
• RF signals were delivered to a 5G circuit with low insertion loss: -0.7 dB at 28 GHz and -1.9 dB at 39 GHz.

Conclusions:

• The metallic pogo-pin probe card design successfully addresses signal leakage and coupling loss in multi-port RF environments.
• The prototype exhibits excellent low-loss and high-isolation characteristics, suitable for high-frequency applications.
• This design facilitates the transmission of multiple RF signals without distortion, paving the way for improved RF system performance.