Nancy Friedrich / Editor

Every holiday season, it seems that "top product" lists are everywhere. They cover everything from the most popular toys to the most in-demand gadgets. Here at Microwaves & RF, we come out with our own list of "Top Products" every December. It is unlikely that the average consumer has heard of or will hear of any of these products. Yet they have impacted the microwave industry - be it through new performance heights, an unusual blending of capabilities and features, or by achieving an industry first. Our criteria for picking these products are straightforward but stringent. From software to oscillators and test equipment, they exemplify what microwave designers need to bring a design from conception to production. Of course, so many outstanding products are spawned each year. To limit our list, we make sure that each product is broadly applicable to many engineers in this industry (see table).

The lightweight, battery-powered spectrum analyzers that graced the January cover hail from Anritsu Co. (www.anritsu.com). The models MS2721B, MS2723B, and MS2724B offer frequency ranges of 9 kHz to 7.1 GHz, 9 kHz to 13 GHz, and 9 kHz to 20 GHz, respectively. The highest-frequency model, which includes a built-in preamplifier and AM/FM/SSB demodulators, weighs less than 8 lbs. These Spectrum Master handheld instruments were based on a product line that previously included both economy and lower-frequency modes operating to 7.1 GHz. The newer models promise to deliver lower noise levels than those earlier models. In addition, a low-frequency extension supports near-audio testing while a high-frequency ceiling allows the capture of the majority of microwave signals.

A Top Product honor also goes to a spectrum analyzer from Rohde & Schwarz (www.rohde-schwarz.com). The model FSU67 covers 20 Hz to 67 GHz with a single coaxial connection and without the help of external frequency mixers. The spectrum analyzer integrates an instrument-controlled RF attenuator with a range of 0 to 75 dB in 5-dB steps. That attenuator eliminates the need for the external, manually operated step or rotary attenuator associated with harmonic mixers. The instrument also flaunts an impressive reference-level range of -130 to +30 dBm.

In the area of semiconductor measurements, Maury Microwave (www.maurymw.com) made news with its High- Gamma-Tuner (HGT) load-pull tuners. These tuners allow direct on-wafer GSM/EDGE load-pull measurements at RF output power levels to +35 dBm. The HGT series of automated tuner systems achieves voltage standing wave ratios (VSWRs) as high as 150:1 for on-wafer and in-fixture load-pull measurements on devices with impedances of 1O or less. The test data that these systems can provide promises to reduce modeling and process uncertainties while cutting process development time for RF power transistors, amplifiers, and modules at frequencies from 825 MHz to 6 GHz.

The February Cover spotlighted the fast-settling frequency synthesizer (FFS) series of miniature synthesizers from Synergy Microwave (www.synergymwave.com), which works to bridge the gap between low phase noise and fast switching speed. One of the first models in this series, the FSFS315555-500, boasts a wide tuning range of 3150 to 5550 MHz and switching speed of just 50 s. That switching speed is measured as the time required to settle to within 10 kHz of a new frequency. In a package measuring only 1.25 X1.00 in., the FSFS315555-500 delivers a minimum of +5 dBm output power over a 2400- MHz tuning bandwidth. Nominal output impedance is 50O. The synthesizer achieves its fast tuning speed in 5-MHz steps. The staff of Microwaves & RF also was impressed by a technique developed by Synergy to trim voltage-controlledcrystal- oscillator (VCXO) phase noise. This patented approach vows to design and optimize the performance of VCXOs to achieve superior phase noise and frequency stability - even if they have relative low quality-factor (Q) resonators (Aug. Cover Story, p. 82).

For the second year in a row, a Top Product title also goes to broadband yttrium-iron-garnet (YIG) oscillators from Micro Lambda Wireless (www.microlamdawireless.com). The MLXB Extreme Wide Band oscillators boast continuous fundamental-frequency coverage of 2 to 18 GHz and 2 to 20 GHz, whereas the MLXS-T Series of broadband oscillators offer switched-band fundamental-frequency coverage of 2 to 18 GHz and 2 to 20 GHz. For the broadband oscillators, spurious levels are -70 dBc or better. Second harmonics are -12 dBc or better while third harmonics are -15 dBc or better.

Wireless communications continues to be a major driver behind product innovation. For industrial-scientificmedical (ISM) applications requiring multiple transistors to reach 1 kW or more, Freescale Semiconductor's RF Division (www.freescale.com/rfpower) came out with the MRF6VP11KH LDMOS fieldeffect transistor (FET). It delivers RF output power of 1 kW at 130 MHz. For signals with a pulse width of 100 s and 20-percent duty cycle, the MRF6VP11KH delivers more than 1 kW at the 1-dB gain compression point with 65-percent efficiency and 27-dB power gain.

To cover all of the major wireless standards/ bands, the digital variable gain amplifiers (DVGAs) from Hittite Microwave Corp. (www.hittite.com) merge wide dynamic ranges with precisely adjustable gain over wide frequency spans. The DVGAs offer the performance of traditional analog VGAs with the simplicity of a digital control interface. The HMC625LP5E, HMC626LP5E, and HMC627LP5E offer a total gain-control range of 31.5 dB. At DC to 6 GHz, the model HMC625LP5 provides the widest bandwidth with typical gain of 18 dB from DC to 3 GHz and 13 dB from 3 to 6 GHz for the maximum gain setting.

This summer saw the release of the first single-chip WiMAX transceiver. Hailing from MAXIM Integrated Products (www.maxim-ic.com), the RF transceiver integrated circuit (IC) supports wireless broadband applications from 2.3 to 2.7 GHz. The MAX2837 accommodates fixed, portable, and mobile WiMAX operation. It incorporates the RF-to-baseband receive signal path as well as the baseband-to-RF transmit signal path. The transceiver is based on an advanced silicon-germanium (SiGe) BiCMOS process, which features low power consumption as well as the low noise figures needed for good receiver sensitivity.

The November Cover Story provides an overview of a Universal Mobile Telecommunications System (UMTS) front end from RF Micro Devices (www.rfmd.com). By leveraging a transmit- module approach, designers can reap the benefits of reduced component placement and size for single-band applications. RFMD's RF6241, RF6242, and RF6245 transmit-module solutions include surface-acoustic-wave (SAW) filters and duplexers. Using a digitally selected low-power mode, they provide reduced current consumption for backedoff (linear) power levels.

Multilayer baluns from Anaren, Inc. (www.anaren.com) also target mobile phones and other portable electronic devices. This non-ferrite transformer's design incorporates the basic impedancetransformation principles that were first described by Guanella and Ruthroff and applied to wire-wound baluns. Yet the new component's form factor is similar to that of ceramic-style SMT baluns. Using a multilayer circuit-fabrication approach, it achieves unprecedented small size. The new multilayer balun also boasts a reduced profile height and "true" SMT package. As a result, lowfrequency baluns can now be considered at the design stage for integration into ultraslim consumer handheld products.

The block-frequency L-band-to-K-band upconverter from Herley-CTI (www.herley-cti.com) targets both commercial and military applications. This block upconverter (BUC) uses dielectric resonator oscillators (DROs) to drive the local oscillator (LO). The BUC is based on computer- modeled mixer spurious analysis and filter designs. It consists of four major sections: the input diplexer and intermediate-frequency (IF) amplifier/ gain-control chain; the mixer, upconverter mixer, filter, and amplifier chain; a low-phase-noise, dual-loop LO; and a DC power supply, bias, and control board. By leveraging computer-aidedengineering (CAE) programs, the upconverter can predict and optimize the performance of its component parts.

The way that microwave engineers use CAE tools is evolving. The AXIEM electromagnetic (EM) simulation software from Applied Wave Research (www.appwave.com) delivers EM analysis as a front-end design tool. Using the software, high-frequency designers should be able to diagnose circuits and structures early in the design flow. The three-dimensional (3D) planar EM simulator was created to simulate the electrical behavior of a wide range of passive high-frequency structures and circuit elements. Examples include MMICs.

The final Top Product of 2007 is an electronically steerable antenna. This low-profile antenna system from AK Electromagnetique, Inc. (Quebec, Canada) can scan electronically in both azimuth and elevation angles. Although the array has been designed for mobile use in the satellite-communications band from 1.520 to 1.665 GHz, it can be used for other frequency ranges and applications. Current designs include three- and five-ring adaptive arrays. The five-ring configuration contains 72 parasitic monopole elements with a groundplane diameter of 54 cm. Its receive gain is 12 to 14 dBi while its transmit gain is 10.0 to 13.5 dBi.