Advances at all levels, from devices and components to subsystems and test equipment, have characterized a year of impressive new-product developments for the industry.
Economically challenging times can spur some of the more innovative product developments. In 2010, the economic obstacles loomed large. But still, RF/microwave companies responded with products that filled many needs with combinations of higher performance, smaller size, and lower costs. The Top Products of 2010 (see table on page 94), as selected by the Editors of Microwaves & RF, represent just a small sampling of the many new products introduced during 2010. These companies are to be applauded for their achievements. Yet, all those RF/microwave companies involved in new-product development in 2010, in spite of the difficult economic conditions, deserve credit. In the end, it is those new products that can help to turn around even a struggling world economy.
As in most years, significant product developments could be found at different levels, from devices through test equipment. At the device level, for example, Microsemi Corp. announced its model 0405SC-2200M silicon-carbide (SiC) transistor for ultrahighfrequency (UHF) pulsed radar systems operating from 406 to 450 MHz. Capable of 2.2 kW output power over that range, the common-gate, Class AB SiC transistor is constructed with 100-percent gold metallization and gold bond wires in a hermetic package for high reliability. The depletion-mode static-induction transistor (SIT) can operate into a termination equivalent to a 5.0:1 VSWR without damage or even degradation in performance. It achieves 8-dB typical power gain across its bandwidth when operating with medium-duration pulses of about 300 s at a 6-percent duty cycle. The drain efficiency is 45 percent at 450 MHz while running on a supply voltage of +125 VDC.
While solid-state power devices grow in output capabilities, manufacturers of vacuum-tube devices such as travelingwave tubes (TWTs) are hardly watching on the sidelines. Rather, firms like e2v continue to push the state of their technologies, with such achievements as the wideband model N20180 TWT in 2010. The miniature helix TWT is capable of as much as 160 W output power within the 2-to-18-GHz range. The tube delivers at least 10 W at 2 GHz and 100 W at 18 GHz with at least 140 W output power from 6 to 13 GHz. It boasts better than 40-percent efficiency in a package measuring just 220 x 26.8 mm and weighing no more than 400 g. The design features a dual-stage collector with conduction cooling for enhanced long-term reliability. The maximum small-signal gain is 71 dB at 9 GHz and 70 dB at 11 GHz.
Several power-detection devices made the Top Products list, with the HMC1020LP4E and HMC1021LP4E single-ended, single-channel root-meansquare (RMS) power detectors from Hittite Microwave Corp. providing dynamic ranges as wide as 73 dB over a frequency range of DC to 3.9 GHz (see p. 87 in this issue). The single-ended, dual-channel model LTC5583 RMS detector from Linear Technology covers 40 MHz to 6 GHz to handle most of the wireless communications standards, including third-generation (3G) and fourth-generation (4G) cellular communications networks. It can measure both peak and average power levels on the two channels over a better than 60-dB dynamic range, at power levels from -59 to +4 dBm, depending upon frequency. Its typical linearity is better than 1.0 dB through 6 GHz. The LTC5583 can be used to measure forward power, reverse power, or a combination of the two by applying its two channels at different test points in a circuit. The two matched detector channels are useful for applications such as monitoring and controlling RF amplifier stage gain.
For power-handling capabilities, the third-generation of Xinger surfacemount- technology (SMT) couplers from Anaren Microwave offered enhanced performance by way of reduced insertion loss compared to earlier generations. The Xinger III couplers, available for coverage from 600 to 2900 MHz, measure just 0.250 x 0.200 in. with less than 37 percent insertion loss of earlier models and more than 100-W CW power-handling capability for all frequencies across the full coverage range. For level control, Analog Devices introduced a line of digital variable gain amplifiers (DVGAs) with as much as 31.5-dB amplitude control for intermediate-frequency (IF) applications through 1 GHz. They offer various step sizes with accuracy as good as 0.2 dB. And for routing signals, a line of GaAs pHEMT switches from M/A-COM Technology Solutions features settling times as fast as 20 ns from 10 MHz to 20 GHz.
YIG oscillators have long been valued for their excellent phasenoise performanceone of the reasons that these tunable frequency sources have often been used in test equipment and critical military electronics systems. But the penalty for the wide bandwidths and excellent spectral purity of YIG oscillators has been the large size needed to house the magnetic structure and its associated tuning coils. Over the years, most YIG source designers have mentioned the goal of building an oscillator that would fit into a package as small as a TO-8 can. That goal at one time appeared unattainable, until the introduction of the MLTO series of permanent-magnet YIG-tuned oscillators from Micro Lambda Wireless, available in standard and custom frequency bands from 2 to 8 GHz. The lowestprofile models in the group (Fig. 1) offer a height of just 0.27 in. An example of the product line is model MLTO-20204, which tunes the octave from 2 to 4 GHz with +10 dBm output power and 10 MHz frequency stability with temperature. Spurious levels are maintained at -70 dBc with harmonics at -15 dBc. The phase noise is what one would expect from a YIG, even one this small, at -100 dBc/Hz offset 10 kHz from the carrier and typically -128 dBc/Hz offset 100 kHz from the carrier.
One of the more interesting product developments in 2010 involved the development of a "product within a product," the active inductors used in a line of low-noise voltage-controlled oscillators (VCOs) developed by Synergy Microwave. Suitable for monolithic fabrication, These tunable active inductors (TAIs) are a fraction of the size of conventional spiral inductors making them suitable for use in monolithic oscillator designs. When incorporated in a 12-GHz VCO as part of a dynamic-phase-injection circuit meant to reduce phase noise, the TAIs afforded a moderate tuning range at 12 GHz with lower phase noise than achieved with similar designs using varactor tuning. Based on a silicongermanium (SiGe) heterojunctionbipolar- transistor (HBT) active device, the 12-GHz VCO was able to achieve a 200-MHz tuning range with only 12 mA and +3 VDC bias.
By integrating multiple VCOs with digital control, the DTO-12000-50M digital tuned oscillator (DTO) from Phase Matrix can serve electronic-warfare (EW) systems from 9 to 15 GHz while requiring only 4 s to tune within 2 MHz of a new frequency. Housed in a package measuring only 4.0 x 3.0 x 0.5 in. (Fig. 2), the DTO delivers at least +15 dBm output power across its frequency range. Integration was also a key in the development of the model 81000 satellitecommunications (satcom) transceiver from Narda Microwave-East. The L-band/ Ku-band subsystem transmits with as much as 13 W power, in a package measuring just 15 x 6.25 x 3.25 in.
With a product on the Top Products list for the first time, Noise eXtended Technologies S.A.S (NoiseXT) from Elancourt, France made a major contribution to the measurement of phase noise with its Dual-Channel Phase Noise Test System (DCNTS). By adopting a modular architecture for the instrument, NoiseXT offers an instrument capable of detecting phase noise at levels as low as -190 dBc/Hz.
The two-channel instrument employs a dual-demodulator architecture and cross-correlation techniques to minimize the effects of its own circuitry's noise on the measured results, applying from 1 to 100,000 correlations to a measurement to lower the noise floor. Of course, the penalty for using a larger number of correlations (for lower noise floors) is slower processing speeds and a longer wait for measurement results. But for oscillators and synthesizers with extremely low noise, this instrument provides the ultimate resource for lowlevel noise measurements. A customer can select a required configuration based on the number and type of modules, with absolute phase-noise measurements at offsets from 0.01 Hz to 40 MHz possible over carrier frequency ranges of 2 to 1800 MHz, 2 MHz to 26.5 GHz, 2 MHz to 40 GHz, and 2 MHz to 50 GHz.
The need to characterize new components and devices continues to drive new developments in test equipment, in most cases building on the strong foundations established by earlier product introductions. Anritsu , for example, enhanced its lines of VectorStar vector network analyzers (VNAs) to support nonlinear device measurements. The analyzers feature dynamic ranges of 123 dB to 20 GHz and 100 dB to 110 GHz. Maury Microwave continued to improve its lines of active and passive load-pull impedance-tuning systems for nonlinear measurements, working in conjunction with suppliers such as Agilent Technologies and AMCAD Engineering.
Among the measurement tools available to RF/microwave engineers, oscilloscopes may be the most versatile, and 2010 marked the first year that more than one of these workhorse instruments appeared on the Top Products list. For venerable test-equipment supplier Rohde & Schwarz, it represented a first step into a new market, with the launch of the firm's RTO series of real-time oscilloscopes. The firm introduced four models, two- and four-channel instruments with real-time bandwidths of 1 or 2 GHz and real-time sampling rates to 10 GSamples/s. In terms of pure speed, the DPO, DSA, and MSO70000C series of oscilloscopes from Tektronix offer improved sampling rates to 100 GSamples/s with as much as 20-GHz bandwidths on as many as four measurement channels (see p. 101 in this issue). Not to be outdone, Agilent expanded its Infiniium digital oscilloscopes with the Infiniium 90000 X-series instruments with sampling rates as high as 80 GSamples/s but real-time analysis bandwidths to 32 GHz. The scopes leverage a custom multichip-module (MCM) circuit based on indium-phosphide (InP) device technology to achieve the impressive bandwidths.