Attendance was modest at this year’s IEEE Microwave Theory & Techniques Society (MTT-S) annual conference and exhibition, held recently in Boston, MA. But bleak economic forecasts didn’t stop this industry’s resourceful engineers from unleashing a host of new product ideas that can only help to turn business in a positive direction.

Among the most noticeable of display booths were those hosted by the major test and measurement and computeraided- engineering (CAE) software suppliers. Those riding the “down” escalator at the entrance of the exhibit floor, for example, were greeted by the outline figure of “Microwave Legend” James Clerk Maxwell overlooking the Sonnet Software booth. Sonnet’s high-quality planar electromagnetic (EM) analysis software and generous offers of free trial copies of their EM software suites drew more than their fair share of visitors from that escalator with scores of booths beyond promoting new software, hardware, and test equipment.

For Ansys subsidiary Ansoft, IMS provided an opportunity to introduce new high-performance computing capabilities for its three-dimensional (3D), full-wave high-frequency-structuresimulator (HFSS) electromagnetic (EM) field simulation software. Among the planned enhancements to this software is domain decomposition, a high-performance- computing (HPC) option. This technology enables engineers to solve problems like electromagnetic-induced heating in high-power microwave structures and antenna performance while under mechanical deformation via links with the ANSYS Workbench platform.

Analysis of the 3D EM effects of components like radio-frequency integratedcircuit (RF IC) packages, antennas, and printed-circuit-board (PCB) interconnects is performed by Electromagnetic Professional (EMPro), which hails from Agilent EEsof EDA (www.agilent.com). It allows designers to create 3D components that can be simulated together with planar two-dimensional (2D) circuit layouts and schematics within the firm’s Advanced Design System (ADS) suite of software tools using EM-circuit cosimulation. Engineers can set up and run analyses using both frequency-domain and time-domain 3D EM simulation technologies.

HSPICE RF from Synopsys performs both frequencyand time-domain steady-state and noise analysis for RF ICs. It offers harmonic balance for weakly to mildly nonlinear circuits, Shooting Newton for strongly nonlinear circuits, and envelope analysis for complex modulated RF waveforms. S-parameter analysis targets smallsignal, linear distributed components. This software promises to quickly and accurately simulate more than 10,000 active devices.

Perhaps the most noticeable trend among the larger test and measurement companies was the engineering efforts devoted to nonlinear vector network analysis. The use of X-parameters, as Agilent Technologies terms its nonlinear versions of small-signal S-parameters, allows designers of amplifiers and other active components to understand the behavior of their circuits under largesignal or nonlinear conditions, such as under saturation or gain compression. Such behavior is of particular interest to developers of systems that must operate with high ratios of peak to average output power. The measurements can be used to build device and component models in CAE tools like ADS.

One of the system-level solutions on display at the Agilent booth included impedance tuners from Maury Microwave Corp. (Fig. 1) bundled with a model PNA-X microwave VNA from Agilent. Additional solutions added mechanical impedance tuners from Focus Microwaves to a microwave PNA-X VNA Nonlinear VNA measurement solutions were also on display at the Rohde & Schwarz booth as well as the Anritsu Co. booth, where the company showed its VectorStar Broadband ME7828A VNA with frequency range of 70 kHz to 110 GHz.

Anritsu also announced its MN469xA series four-port test sets for its high-performance VectorStar MS4640A VNAs. The test sets provide four-port measurement capability through 70 GHz without rerouting test cables. The combination of test sets and VNAs team for accurate measurements at speeds to 30 microseconds per point with 103-dB dynamic range through 67 GHz. The company also displayed several additions to its VNA Master line of handheld VNAs for in-field testing..

One of the more intriguing nonlinear measurement solutions was offered by little-known Mesuro Ltd. based in Cardiff, UK. The firm’s MB series of test sets (Fig. 2) support active load-pull measurements in contrast to mechanical impedance tuners. The test systems are ideal for measuring the nonlinear behavior of PAs with output levels as high as 150 W CW. The systems were used in tandem with the Microwave Office Design Environment 2009 of CAE tools from Applied Wave Research (AWR) to develop the “Cardiff Model” to characterize power transistors and amplifiers with any type of signal waveform and in any impedance environment.

According to Dr. Richard Emsley, CEO of Mesuro, “The Mesuro active load pull solutions are an exciting advancement in measurement technology that will greatly reduce challenges facing device and PA designers today. The scientists at Cardiff University have worked closely with industry leaders for many years and Mesuro has developed a very practical commercial solution.” The new openloop, active load-pull technique replaces the use of passive tuners with an RF source that adjusts the amplitude, phase, and power level to vary the effective impedance at the DUT interfaces. The solution allows absolute control of all in-band and out-of-band impedances, enabling the designer to control the harmonic source/load impedance over the entire Smith chart.

OEwaves addressed phase-noise measurements at MTT-S—specifically with its automated phase-noise measurement system based on a homodyne receiver. The test system is available for a standard measurement range of 6 to 12 GHz with extensions bringing the frequency coverage as high as 40 GHz. The base phase noise is as low as –120 dBc/Hz offset 1 kHz from the carrier and –170 dBc/Hz offset 10 MHz from the carrier using resolution bandwidths from 0.1 Hz to 200 kHz. The test system can display spectral density, spurious content, and full spectrum information. It also can be configured for pulsed CW input signals.

Thanks to a new synthesizer design, the model 2820A VSA from Keithley Instruments offers a low-phase-noise option (Fig. 3). At a 300-kHz offset from a 2-GHz carrier, for example, phase noise is less than –140 dBc/Hz. The dynamic range of errorvector- magnitude (EVM) measurements can therefore be as low as –48 dB for 20-MHz IEEE 802.11n measurements. The standard VSA provides a 40-MHz signal-acquisition bandwidth with a frequency range of 400 MHz to either 4 or 6 GHz. To provide higher testing speed, it can tune to a new frequency in 250 s.

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