May 3, 2016
Development of high-frequency components used in 4G and 5G designs has placed greater pressure on engineers working for design houses. Helping to alleviate this burden are instruments such as Vector Network Analyzers (VNAs), which are used to conduct S-parameter measurements as part of the validation process associated with complex designs. The VNA has evolved to accommodate the intricacies associated with these emerging high-speed applications.
To better meet the testing requirements at higher frequencies, a microwave integrated circuit (MMIC)-based nonlinear transmission line (NLTL) technology, also known as shock line, has been developed by Anritsu. NLTL technology is used to generate very narrow pulses over an extremely wide range of microwave and millimeter frequencies. The result is higher dynamic range for improved measurement accuracy. The consequence is high performance, broadband measurement capability in small modules. VectorStar® is one series of Anritsu VNAs that utilizes NLTL technology.
This novel approach has advantages over the step recovery diode technology and waveguide-based components approach taken by traditional VNAs. This latter, mature architecture results in large and expensive instruments with limitations, particularly for high-frequency designs.
Compact Modules = Greater Accuracy
The VectorStar broadband VNA system (figure 1) delivers wideband performance in a very unique way. Because of the compact design, it is possible to connect the modules directly to the wafer probe, thereby eliminating coaxial cables between the probe and the VNA modules. As a result, the accuracy of the VNA over extremely broad bandwidths is unsurpassed. The VectorStar allows measurement of active and passive devices, including noise figure up to 110/125/145 GHz in a single system and with minimal system reconfiguration.
The VectorStar E- and W-band (mm-wave) system incorporates high-performance compact mm-wave modules in an economical extended E- or W-band configuration. The compact size and weight of the mm-wave modules (0.6 lb. vs. 7+ lbs. of competitive options and 1/50 the volume) allow engineers to easily configure a high-performance waveguide banded system for demanding measurement and installation challenges. The compact modules are optimal for waveguide measurements where traditional large and cumbersome mm-wave modules provide limited power control and poor stability.
Success Story: activCirk
One design house that has leveraged the advantages of the NLTL architecture is activCirk, which develops integrated circuits for high-frequency applications and products. The Newbury Park, CA company specializes in the design and test of MMICs of all flavors using InP, GaN, and GaAs technologies for E-, V- and W-band applications. By using the VectorStar VNA, engineers have been able to reduce time-to-market on their MMICs while also having greater confidence in their designs.
activCirk MMIC engineers develop wide-band transistor and circuit models that are typically not provided by the foundry at the bandwidths required for mm-wave MMIC design. They require a network analyzer that can make very accurate measurements at high speeds to acquire results over several entire wafers. A VNA, such as VectorStar, that combines linear, nonlinear and noise figure measurements with minimal external programming has proven to be extremely beneficial. It can rapidly produce statistical models of circuit and transistor performance.
“Anritsu delivers technical leadership with the VectorStar VNAs, which are adept at wideband accurate measurement for device modeling, as well as high-speed product-centric testing for MMIC products. This VNA is an extremely powerful platform for large quantities of difficult test challenges,” said Perry Macdonald, Technical Director, activCirk Corporation.
To learn more about the NLTL architecture in the VectorStar VNA series and the benefits it can bring to high-frequency designs, download a white paper.