Launcher-in-Package RF Testing Using Through-Board Waveguide Loopback
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Solution Overview
Problem
Conventional testing methods for RF devices with integrated launchers are costly and inefficient for mass production due to the need for expensive equipment and complex connectivity, especially at mmWave frequencies, making them impracticable for large-scale testing.
Innovation Solution
A two-stage test process using a loop-back test process and an RF-accurate test process, where the loop-back test process employs a test jig with a loop-back structure and less expensive equipment for rapid testing, and the RF-accurate test process provides characterization data for correlation, allowing extrapolation of RF-accurate results for larger-scale testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing methods using VNAs, power meters, and external signal generators are employed, then measurement precision is improved, but testing cost increases significantly
Solution Approach 1:
The patent creates a simplified test environment by copying only the essential waveguide transmission characteristics needed for testing, rather than using the full conventional VNA-based measurement system. The loopback structure replicates the RF signal path through waveguides, allowing basic functionality verification without expensive external equipment.
Solution Approach 2:
The patent employs a disposable or reusable test fixture with integrated waveguides and loopback structures that can be manufactured at low cost. This fixture is designed for single-use or limited-use testing scenarios where high precision is not critical, replacing the need for expensive, delicate VNA probes and connectors.
2Measurement precision
If conventional testing methods with manual placement in compact chambers are used, then measurement precision is improved, but productivity decreases due to manual operation
Solution Approach 1:
The test fixture is designed to be self-contained with integrated waveguide paths and loopback structures that automatically route RF signals without requiring manual probe placement or adjustment. The fixture itself performs the signal routing and measurement functions that would otherwise require operator intervention with external equipment.
Solution Approach 2:
The patent combines multiple testing functions (signal transmission, reception, and measurement) into a single integrated fixture. The waveguide channels, loopback structures, and measurement points are merged into one compact assembly that can be quickly connected to the device under test, eliminating the need for separate manual setup steps.
3Measurement precision
If precise connections between IC package I/Os and external test equipment probes are provided, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary test fixture that mediates between the IC package and the external environment. This fixture contains waveguide channels that extend through its structure, providing a direct RF signal path from the package launchers to the loopback structures without requiring direct connection to external VNA probes or signal generators.
Solution Approach 2:
The fixture copies the essential waveguide transmission functionality needed for testing directly into its structure. Rather than connecting to external equipment that provides waveguide paths, the fixture itself contains the waveguide channels, eliminating the need for complex external connections while maintaining the required RF signal transmission characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates efficient and cost-effective mass production testing by correlating loop-back test results with RF-accurate data, enabling precise characterization of RF devices without the need for extensive equipment setup and long test durations.
Implementation Method 1
The plunger also includes at least one waveguide. Each waveguide extends through the plunger for routing electromagnetic radiation transmitted by one of the transmit elements of the device to one of the receive elements of the device.
Implementation Method 2
Each waveguide comprises a plurality of waveguide openings for coupling electromagnetically to corresponding radiating elements of the device.
Data Source
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AI summary
A two-stage test process for testing IC packages having integrated launchers includes a first stage in which an RF-accurate test process is used to perform RF-accurate tests on a sample set of IC packages to obtain RF-accurate test results and a loop-back test process is performed to obtain loop-back test results. Test characterization data is obtained by comparing the RF-accurate test results to the loop-back test results. In a second stage, larger-scale testing is performed solely with the loop-back test process, and the loop-back test results for each tested IC package are compared with the test characterization data to characterize the test operation of the tested IC package. The loop-back test process can employ a test jig employing a PCB-mounted or PCB-integrated loop-back structure for relatively rapid test setup and test processing.