Paper: Early Defect Detection with a Scalable Broad-Spectrum Test Using Radiofrequency Reflectometry

Presented at IPC Apex 2025, our research evaluates RF reflectometry both qualitatively and quantitatively.

​​Abstract​ 

This work explores radio frequency (RF) reflectometry as an early-stage defect detection technology for electronics. In-circuit testing (ICT) is limited to fully assembled boards, while automated optical inspection (AOI) focuses on surface-level defects, missing issues like internal solder voids or microcracks. The work qualitatively and quantitatively evaluates RF reflectometry. The qualitative evaluation compares RF reflectometry to alternative approaches in their suitability to early-stage defect detection. In the quantitative evaluation, we conducted a controlled experiment on a complex product demonstrating surprisingly good defect coverage, even in adversarial testing conditions through only a connector. 

Uncovering Hidden Defects Earlier in the Electronics Manufacturing Process

In electronics manufacturing, traditional inspection methods often fall short. They miss small but critical issues like micro-cracks, solder inconsistencies, or early signs of component wear. These techniques also can’t reliably detect unauthorized changes, tampering, or fraud. The result? Defects are found too late — driving up internal failure costs and inflating the overall Cost of Poor Quality (COPQ).

What the industry needs is a testing approach that’s sensitive, non-invasive, and efficient — capable of catching problems early in the production process. Early detection means fewer defects per million units (PPM), less rework, and a consistently high-quality product.

In electronics manufacturing, traditional inspection methods often fall short. They miss small but critical issues like micro-cracks, solder inconsistencies, or early signs of component wear. These techniques also can’t reliably detect unauthorized changes, tampering, or fraud. The result? Defects are found too late — driving up internal failure costs and inflating the overall Cost of Poor Quality (COPQ).

What the industry needs is a testing approach that’s sensitive, non-invasive, and efficient — capable of catching problems early in the production process. Early detection means fewer defects per million units (PPM), less rework, and a consistently high-quality product.

What the Ideal Solution Should Deliver

To be effective on the production floor, the technical solution must meet five key criteria:

Non-Invasive Testing

The method must assess product quality without damaging or modifying the unit under test (UUT). By avoiding physical probing or disassembly, non-invasive testing enables faster, repeatable quality checks that reduce internal failure costs and improve process efficiency.

Timely and Cycle-Time Friendly

Testing must be fast — it should integrate seamlessly with rapid production cycles. Delays in testing can slow down the line, create bottlenecks, and drive up costs. The solution must keep pace with high-throughput electronics manufacturing.

Works with Partial Assemblies

The ability to inspect partially built units is critical. For example, defects introduced between soldering stages need to be caught before full assembly. A solution limited to final-stage testing misses this opportunity for early intervention.

Universally Applicable Across Products

A single testing framework that works across various designs streamlines quality control. It reduces training requirements, operational complexity, and tooling costs — while enabling consistent defect detection early in production.

High Coverage, High Density (HC/HD)

The method must thoroughly inspect all key components and connections — especially on compact, densely packed boards — to ensure comprehensive defect detection.

Blackbox-Compatible

The testing process should not require internal design knowledge. With a blackbox approach, engineers can validate functionality without knowing what’s inside — ideal for proprietary, complex, or evolving product architectures, such as modular sub-assemblies.At IPC Apex 2025, we introduced a novel approach to early-stage defect detection in electronics using radio frequency (RF) reflectometry. Traditional in-circuit testing (ICT) only works after boards are fully assembled, and automated optical inspection (AOI) tends to miss deeper issues like internal solder voids or microcracks since it focuses on surface-level flaws.

Traditional in-circuit testing (ICT) only works after boards are fully assembled, and automated optical inspection (AOI) tends to miss deeper issues like internal solder voids or microcracks since it focuses on surface-level flaws.

Our research evaluates RF reflectometry both qualitatively and quantitatively. On the qualitative side, we compared it with other inspection methods to assess how well each can catch early-stage defects. On the quantitative side, we ran a controlled test using a complex product and were able to detect a broad range of defects — even in challenging conditions, and impressively, using only a signal passed through a connector.

To get the full results and methodology, download the technical paper.