Maury Microwave
There is a growing demand for device characterization and modeling solutions above 28 GHz to support applications such as 5G frequency range 2 (FR2) and automotive RADAR as well as next generation semiconductor technology evaluation. These applications are not only driving frequencies higher but are also pushing the envelope on modulation bandwidths. To address these challenges, our state-of-the-art semiconductor test solutions push the boundaries of load pull with extreme modulation bandwidths as well as expanded frequency coverage to 1.1 THz.
The introduction of 5G is unlocking new levels of mobile communication performance with high speeds, low latencies and ultra-high reliability. This will be enabled in part by using the FR2 frequency bands around 28 and 38 GHz, with channel bandwidths in the hundreds of MHz. These bandwidths pose a challenge for passive impedance tuners, where the phase variation over frequency results in the loss of impedance control and degrades ACPR, EVM and PAE performance when using wideband modulated signals. To overcome this challenge, Maury designed the MT2000 mixed signal active load pull system, which corrects for impedance phase variations and allows users to set arbitrary impedances over a bandwidth of up to 1000 MHz at frequencies up to 40 GHz (see Figure 9).
Figure 9. Maury MT2000 mixed signal active load pull system.
With wideband impedance control, Maury can now synthesize the load conditions presented by realistic matching networks and antennas and accurately characterize the vector-corrected performance of a DUT. To achieve this capability, they designed the MT2000 from the ground up as a standalone one-box solution, which replaces the functions of a VNA, vector signal generator, vector signal analyzer and automated impedance tuners, thereby reducing the overall system cost and complexity while simultaneously ensuring an excellent measurement accuracy. Additional features of the MT2000 include high speed CW and pulsed-CW measurements, baseband impedance control, time-domain nonlinear analysis, behavioral model extraction for 5G circuit design, and I/Os for digital pre-distortion and envelope tracking tests.
When active devices are characterized at frequencies beyond 5G, additional challenges for passive impedance tuners arise, especially for on wafer measurements. Traditional on wafer passive load pull systems suffer from a degraded tuning range at the DUT reference plane due to the insertion loss of the RF probes used to make a connection with the DUT. While a standalone passive impedance tuner may be able to present a |Γ| > 0.9 at 75-110 GHz, the system loss may reduce the tuning range to |Γ| = 0.6-0.65, often below the expectations of a modeling or design engineer. The latest vector-receiver load pull system using IVCAD software, designed in partnership with AMCAD Engineering, enables hybrid-active load pull up to 110 GHz, and is able to increase the tuning range to |Γ| = 0.92 or higher at the DUT reference plane. The increased tuning range allows engineers to fully characterize their transistor technologies, determine ideal matching conditions for amplifiers and circuit designs, and better validate their nonlinear models. To best support their customers, the company is expanding the MPA-series amplifier product line to include high-power mmwave amplifier modules in bands between 50 and 110 GHz for active and hybrid-active load pull.
At frequencies above 110 GHz, the system losses become so high that the impedance tuning range of passive tuners is significantly limited. As an example, a 4 dB insertion loss of a waveguide probe at 300 GHz would reduce a hypothetical tuner’s |Γ| > 0.9 to less than 0.3 at the probe tip. To overcome this challenge, Maury offers fully active load pull up to 1.1 THz with their strategic partner Vertigo Technologies and our MMW-STUDIO solution. MMW-STUDIO uses standard VNAs and waveguide extenders (e.g. Keysight and R&S VNAs using VDI or OML extenders) and enables high-resolution amplitude- and phase-controlled S-parameter, power sweep and load pull measurements with |Γ| > 0.9 at the probe tip at frequencies up to 1.1 THz (see Figure 10). With MMW-STUDIO, engineers can now extract and validate transistor models, full characterize transistors and circuits, optimize amplifier design and validate the performance of circuits and systems under mismatched load conditions at mmW and sub-THz frequencies.
Figure 10. Active load pull up to 1.1 THz with their strategic partner Vertigo Technologies and our MMW-STUDIO solution
NI (National Instruments)
Many companies working on mmWave devices for 5G applications are still defining the final architecture of their devices, how to package them and what level of performance they can achieve. Since these factors are not final, engineers working on applications need flexible mmWave test and measurement solutions. NI is in a unique position to offer this flexibility and the speed required to take measurements on a broad range of mmWave device types.
Taking advantage of the modularity of the software-connected PXI platform and mmWave Vector Signal Transceiver (VST), NI offers a test solution that is easy to configure to fit the needs of 5G mmWave devices. The mmWave VST, a wideband instrument that combines a vector signal generator and vector analyzer, is capable of covering both 5 to 21 GHz intermediate frequency (IF) and 5G frequency range 2 (FR2) mmWave bands. The compact mmWave test heads, which are external to the PXI chassis, minimize signal loss by bringing the signal closer to the DUT interface and are easy to adapt to physically different test setups (see Figure 11).
Figure 11. NI VST, mmWave modules and software for 5G mmWave testing.
In addition, engineers can select either direct or switched-path configurations of the NI mmWave test heads. This flexibility helps achieve the best measurement performance depending on the DUT types, whether they are higher-power devices or multichannel types such as beamformers. Figures 12 and 13 show different types of test configurations taking advantage of the mmWave VST architecture.
Figure 12. NI mmWave VST connected to a 32-channel – IF-RF Beamformer.
Figure 13. NI mmWave VST configured for over-the-air (OTA) testing of IF to RF Antenna Modules.
5G semiconductor companies continue to forge new developments in antenna-in-package (AiP) and antenna-in-module (AiM) devices. NI introduced a 3D-scanning mmWave OTA validation solution that helps characterize the spatial radiation performance of these devices 5 to 10 times faster than traditional scanning techniques. This solution can be adapted to high volume parametric OTA production test using the same instrumentation, which helps ensure reliable AiM performance once assembled as part of a system.
Additionally, NI’s modular instruments, like the mmWave VST, readily deploy to high volume semiconductor manufacturing floors within the NI Semiconductor Test System (STS). The STS takes advantage of the same measurement science and high-precision lab instrumentation in a robust automated test equipment (ATE) FormFactor. STS maximizes yield on the production floor by leveraging lab-grade measurement performance while applying highly optimized measurement algorithms to accelerate test speed. Furthermore, our vision is to connect the performance insights from a large amount of characterization and sample data to create more targeted and efficient test methodologies and sequences. Then, by mining production data, we can understand how to improve the initial design and validation stages, and further accelerate the rapid design-to-production cycle of mmWave devices.
NI offers a test solution that empowers engineers across different stages of mmWave device testing – from validation to automated characterization to production test. The commercialization of mmWave devices is new and exploding. NI’s high-performance, flexible mmWave test solution solves the challenge of testing a variety of devices in a condensed timeline while ensuring the highest device quality.
