1. The CGH31240F and CGH35240F amplifiers use GaN-on-SiC technology to achieve 240 W saturated output power at frequency ranges of 2.7 to 3.1 GHz and 3.1 to 3.5 GHz, respectively. Cree, Inc..>
2. The latest addition to the GORE PHASEFLEX line of RF/microwave test cable products is an 18-GHz assembly that can withstand 100,000 flexures at a minimum bend radius of one inch. W. L. Gore.>

THE HIGH-FREQUENCY industry's fortitude was showing at the recent 2011 International Microwave Symposium (IMS), which took place June 5 to 10 in the Baltimore (MD) Convention Center. Not only were exhibition aisles and technical sessions fi lled, but a good number of companies chose this event to launch or announce their latest products. A wide range of goods was covered, from components and software to test equipment and complete systems. And many application areas were served, from traditional electronic-warfare (EW) receivers to emerging applications in automotive and medical industries. About 9000 visitors attended IMS 2011, taking in an exhibition fl oor with over 600 companies.

On the exhibit floor, Communications Power Corp. displayed tall racks of power amplifiers for nuclear-magneticresonance (NMR) and magnetic resonance imaging (MRI) medical applications. These complete amplifier systems operate in bands from 100 kHz to 2.1 GHz with output-power ratings to 2.4 kW and are capable of producing magnetic field strengths to 48 T (see Microwaves & RF, March 2011, p. 98).

On a smaller scale, Anaren launched a line of Xinger III Doherty power combiners for applications from 0.6 to 2.7 GHz. A fraction of the size of traditional Doherty combiners on printed circuit boards (PCBs), these new offerings handle power levels from 50 W (and only 0.2 dB insertion loss) through 200 W (and only 0.15 dB insertion loss) in two different surfacemount- technology (SMT) packages measuring only 6.35 x 5.08 mm and 14.2 x 5.08 mm.

Avago Technologies announced several products based on its 0.25-E-pHEMT process, including the MGA-63xP8 series of LNAs and the model ALM-11-x36 series failsafe bypass LNA modules, for wireless infrastructure applications. The firm also introduced their model AFEM-S257 WiMAX co-existence front-end module, designed to allow WiMAX to co-exist with other cellular and WiFi radios in the 2.5 to 2.7 GHz band. It provides +24-dBm WiMAX-compliant output power with 34-dB transmit gain and 3.5 dB receiver noise figure, operating from a +3 to +5 VDC supply.

A number of different firms, including CTT and M/A-COM Technology Solutions, unveiled new GaN-based products at IMS 2011. Cree, a company perhaps better known for its silicon-carbide (SiC) devices, launched a pair of S-band MMIC amplifiers based on GaN-on-SiC technology, using the SiC base to aid heat dispersal. Cree's model CGH31240F and CGH35240F high-electron-mobility-transistor (HEMT) MMIC amplifiers are rated for saturated output power to 240 W from 2.7 to 3.1 GHz and 3.1 to 3.5 GHz, respectively, with better than 11-dB power gain (Fig. 1).

These GaN amplifiers feature poweradded efficiencies of 60% or more, resulting in low power consumption. Cree's Director of RF, Jim Milligan, noted: "Cree is pleased to offer these industry leading S-Band GaN HEMT devices for a variety of civilian and military applications, such as air traffic control, weather radar, and homeland defense. Thermal management is a key consideration for radar systems and Cree GaN HEMT products are enabling ultrahigh-efficiency solutions, which result in lower dissipated power, simplified power distribution, smaller device footprints, and lighter weight systems."

GaN device supplier Nitronex had announced prior to the show that it had shipped more than 500,000 production devices based on its SIGANTIC GaN-on-Si process. Their first production devices were available in 2006, with high-volume production of GaN devices starting in 2009, so the bulk of these device shipments have occurred over the past two years. As Charlie Shalvoy, Nitronex's President and CEO remarks, "Shipping more than 500,000 devices is a testament to the early successes we've had in military communications, jammers, and cable TV infrastructure. We have also established a robust supply chain with US manufacturing partners based on our proprietary GaN-on-Silicon technology." Other companies at IMS 2011 on hand with GaN devices included Microsemi Corp., RF Micro Devices, and TriQuint Semiconductor.

Centellax clearly defined the meaning of the term "broadband" with several lines of amplifiers for both microwave and optical communications applications, including low-noise model UAPS45SC, a MMIC component with 11-dB gain and 4.5-dB noise figure across an impressive bandwidth of DC to 45 GHz. To top that, the firm also showed off its model UAPS65SC MMIC LNA with 10 dB gain from DC to 65 GHz.

WL Gore & Associates displayed an addition to its GORE PHASEFLEX microwave test cables, an 18-GHz assembly (Fig. 2). Engineered for production, it is available in 1.0 and 1.5 m lengths with SMA or Type N connectors and can withstand 100,000 flexures at a minimum bend radius of 1 in. The assembly's internally ruggedized construction features crush resistance of 187 pounds per linear inch (85 kg/cm). As Rene Burba, GORE Microwave/ RF Test Assemblies Global Product Manager, explains, "We engineered a small, durable microwave/RF cable assembly that reduces costs in production testing by delivering consistently precise measurements in an easy-to-use construction."

Tektronix Component Solutions added to its extensive application-specific-integrated-circuit (ASIC) and field-programmable-gate-array (FPGA) test capabilities with their investment in five new J750EX semiconductor test systems from Teradyne. In addition to testing high-performance ASICs and FPGAs for military, space, and commercial aerospace customers, the new systems can provide memory testing of digital devices with as many as 384 pins. "We are making a significant capital investment to better serve the needs of the high-performance milaero market," says Tom Buzak, President of Tektronix Component Solutions.

Some firms made their presence felt in the technical sessions, including an ongoing series of MicroApps presented on "Agilent Avenue," the aisle alongside the large Agilent Technologies booth. In addition to extensive advice on making successful microwave measurements based on test equipment from Agilent and partners, John Coonrod of Rogers Corporation explained the concept of design dielectric constant, a version of the printed-circuit-board (PCB) parameter that is better suited (than the typical data-sheet value) for modelling purposes in microwave computer-aided-engineering (CAE) programs, including Agilent's Momentum and Advanced Design System (ADS) software tools. John O'Campo of M/A-COM Technology Solutions even spoke at one of the MicroApps about the elements of a successful business merger.

Agilent itself made quite a splash with several major announcements, including the introduction of five new PNA series vector network analyzers (VNAs) for measurement applications through 67 GHz. The highest-frequency unit, model N5227A, operates to 67 GHz with +11 dBm source power at 67 GHz. The other four models have top frequencies of 13.5, 26.5, 43.5, and 50.0 GHz. The PNA series instruments offer a wide range of tests, including measurements of noise figure, gain compression, and two-tone intermodulation distortion (IMD).

National Instruments drew many visitors to its booth because of several activities prior to the show, including the firm's previously announced acquisitions of frequency synthesizer supplier phase Matrix and computer-aided-engineering (CAE) software supplier AWR. The acquisition of Phase Matrix adds considerable expertise in high-frequency signal generationnotably, in fast-switching, low-phase-noise frequency synthesizerswhile AWR brings a well-established position in CAE design tools, including the popular Microwave Office suite of design tools.

In the area of computer modelling, Computer Simulation Technology (CST) introduced a finite-element eigenmode solver for its CST Microwave Studio program with the capability of modelling curved elements of arbitrary order. This allows the calculation of surface currents along curved surfaces, such as those on travelling-wave tubes (TWTs).

In the test and measurement area, Anritsu showed some broadband capability by introducing its model ME7838A VNA system with single-sweep coverage from 70 kHz to 110 GHz, and full operation from 40 kHz to 125 GHz. It eliminates the large frequency-conversion modules of earlier millimeter-wave VNAs and provides real-time power levelling control at power levels as low as -55 dBm. The VectorStar VNA system adjusts power levels through millimeter-wave frequencies without the need of electronically controlled mechanical attenuators and power linearity correction tables. The analyzer features wide dynamic range even at millimeter-wave frequencies, delivering a dynamic range of 107 dB at 110 GHz and 92 dB at 125 GHz.