Broadband 5G technology at mmWave frequencies enables many new data-hungry applications at speeds faster than wired connections for more people than ever before. For end users, this is promising news. 5G will make current wireless speeds feel like trading in an old family car for a new sports car, and the breakthroughs in cellular communications will enable things only seen in sci-fi movies.
However, before you can see these benefits, critical work needs to be done. 5G technology introduces a tough set of test challenges for engineers working on designing, testing, and delivering mmWave 5G devices to market.
Pressing mmWave 5G Test Needs
Testing mmWave 5G semiconductor devices creates several unique test challenges. As engineers, you can no longer rely on the test instrumentation you used for 4G LTE. You need to outfit more capable test benches with test instruments that can handle 5G waveforms from 24 GHz to 44 GHz to characterize and test the performance of new chip types, including multichannel front-end modules, hybrid beamformers, and antenna-in-package (AiP) devices with 8, 16, or more antenna elements. To complicate matters, many of these new chips will require over-the-air (OTA) test solutions because their high level of integration eliminates any accessible RF connectors.
Failing to act quickly and revamp benches for 5G test could leave you trying to characterize, validate, and test new mmWave 5G chips with established, but slow and costly, test technology originally developed for very different industries and applications like mmWave radar, aerospace, and military systems. Test solutions must be purposefully designed for commercial semiconductor applications, and they must be future-proof because 5G technologies will continue to evolve. With more small cells and more phones in the hands of consumers, these solutions also must be able to move new 5G semiconductor devices from the lab to the manufacturing floor in much larger volumes than those used for 4G technology.
New Test Technology
Since wireless technology is constantly evolving, we at NI have been working hard to improve test technology and create DUT-centric solutions to tackle the new 5G test challenges. Our new mmWave Vector Signal Transceiver (VST) gives engineers fast, lab-grade, high-bandwidth signal generation and analysis at different test points along the signal chain of new 5G semiconductor devices.
To that end, we made a set of deliberate engineering decisions to architect the mmWave VST in a modular way. We created an intermediate frequency (IF) VST that plugs directly into the PXI backplane. It has calibrated IF in/out ports to generate and acquire wideband signals between 5 GHz and 21 GHz, and it connects to a separate set of mmWave heads outside the PXI chassis. The mmWave heads then translate the IF signal to mmWave and vice versa.
As part of our DUT-centric strategy, we want to give engineers working on the latest 5G devices more flexibility, so we developed the following three compact mmWave radio head configurations:
2 bidirectional ports
8+8 switched ports
1 direct port and 8 (solid-state) switched ports
Figure 1. mmWave Radio Head Configurations
This approach creates:
A future-proof system that you can adapt without having to change any other part of the test solution as the 5G standard evolves to include higher frequencies
A way to move mmWave measurement ports very close to the DUT, which minimizes frequency signal loss
IF and mmWave signal generation and analysis capabilities
A complete test solution with wide data rates and signal processing at the speed of the latest multicore processors
Figure 2 shows how the mmWave VST complements NI’s RF test hardware for interfacing every point in the signal chain with one system.
Figure 2. Interfacing at Various Signal Points of 5G DevicesUsing your existing baseband VST, you can directly probe the 5G IQ samples. Then, with the IF VST, you can test devices that operate at intermediate frequencies such as IF transceivers and IF-to-RF beamformers. When you connect to the mmWave radio heads, you interface the RF ports of multichannel front-end modules (FEMs) and beamformer devices. Finally, for OTA tests, you route the signals between the measurement antennas inside the RF chamber and the mmWave test heads.
Consider an example of how you can take advantage of the modularity of the mmWave VST to connect to two different types of beamformers (IF to RF and RF to RF) with multiple signal branches:
Figure 3. Connecting to an IF-to-RF Beamformer With the mmWave VST
Figure 4. Connecting to an RF-to-RF Beamformer With the mmWave VST
Bridging the Gap to Production
As the wireless industry moves toward building a connected world on 5G, NI is ready to help its customers test these 5G semiconductors en masse. We’re painfully aware that working with high-bandwidth signals, covering more bands, and testing beamforming devices with no access to RF connectors makes things much harder than it was for 4G devices.
As a practical way to give test engineers cost-efficient, reliable, and high-throughput production test setups for 5G devices, we designed the mmWave VST to integrate natively into the NI Semiconductor Test System (STS). 5G mmWave STS configurations support up to eight mmWave VST instruments, with integrated IF capabilities and up to 72 mmWave ports in a highly-parallel tester configuration that is optimized for EVM performance. You can quickly deploy the same wideband 5G measurement capabilities of validation labs into your test cell with the STS, reducing both the cost and risk of testing 5G parts. Our solution uses the same instrumentation, so your correlation efforts also decrease.
The 5G sports car is roaring, and through our continued cooperation with some of the leading designers and manufacturers of today’s emerging 5G semiconductor devices on DUT-centric solutions, NI is ready to give you the tools you need to bring the 5G connected world to life.