Keysight Helps ASE Reduce Antenna-in-Package Test Time by 20%

Advanced Semiconductor Engineering, Inc. (ASE) is among the front runners in the race to develop high-frequency antenna-in-packages (AiPs) for 5G and automotive applications. ASE recently collaborated with Keysight to improve measurement accuracy and test efficiency of its complex AiP development efforts. The miniature system-level packages use heterogeneous integration, a combination of different process technologies to enable optimization of specific performance characteristics — such as power.

Cutting Edge AiP Presents Significant Design and Test Challenges

Packages running at high frequencies with integrated antennas are not new. However, making packages much smaller, more complex, and much more power-efficient presents unique challenges. For example, 5G devices require an assortment of new technologies such as phased array antennas — an array of antennas with individual radiation elements. Complex integration of multiple antennas and high frequency active and passive components with baseband circuitry raise new signal and power integrity issues.

Test validation of this complex package is also challenging. The devices under test (DUTs) come in multiple sizes with different test pin assignments. The dimensions make it difficult to perform reliable measurements and very time-consuming to optimize the probe station, change adaptors, and to the remove fixture factors. ASE must also provide measurement data to its customers which supports correlation of attributes like return loss (S11) and gain (S21) of the antenna.

PNA Reduces Test Time by 20% — Increases Measurement Confidence

ASE approached Keysight Technologies to collaborate on ways to test their new AiPs at high frequencies — 5G up to 39 GHz and automotive radar up to 79 GHz. Though they were primarily concerned about measurement accuracy, stability, and repeatability, the ASE engineering team also wanted to make these measurements as efficiently as possible.

Keysight’s industry-leading PNA microwave network analyzer helped ASE’s engineering team achieve stability, repeatability, and efficiency. The PNA not only reduced measurement uncertainty, but it also reduced the time spent by engineers on setting up and making measurements. The PNA’s seamless connection with the probe station simplified test setup and the fixture removal and calibration functions automated what were previously time-consuming manual steps. For example, the fixture removal software simplifies complex fixture characterization with an easy-to-follow wizard. The unique Cal All function performs a one-time calibration for all channels. Overall, ASE estimated a 20% reduction in test time.

The PNA also improved measurement accuracy and repeatability. For example, the true-mode stimulus feature provides mismatch-corrected true differential and true common stimuli. The user can characterize in-band and out-of-band interference on two measurement channels simultaneously (one narrowband, one broadband). True-mode stimulus helped ASE closely mirror real operating conditions and raise confidence in the measurement results, particularly at high frequencies.

“Keysight’s PNA-based solution helped us reduce test setup times from hours to minutes,” said CP Hung, vice president of ASE Corporate R&D. “The PNA also delivered stability, repeatability, and reproducibility to dramatically reduce our team’s workload and ensure accuracy of measurement data for our customers around the world.”

In the future, ASE may need to extend their test setup to cover higher frequencies. This is easily doable with Keysight’s PNA, which currently reaches up to 1.5 THz.