Sound business practices include aggressive introduction of new products even during lean times. Even through a difficult year for high-frequency-electronics business in 2004, smart companies continued to support strong research-and-development efforts and rollout innovative new products in the hopes of capturing new markets or increasing market share. The list for Microwaves & RF's Top Products of 2004 is at best a representative sampling of the many innovative products unveiled during this year. Many other companies deserve credit for continuing to innovate during difficult times.

As selected by the editors of Microwaves & RF, the top-product list (see table) includes several signal sources (three frequency synthesizers and a series of voltage-controlled oscillators) and one instrument to test them. The synthesized sources include the UFS series of rack-mount frequency synthesizers from Elcom Technologies (Rockleigh, NJ), the DS Series of rack-mount frequency synthesizers from Herley CTI (Whippany, NJ), and the model AD9956 AgileRF™ direct digital synthesizer (DDS) integrated circuit (IC) from Analog Devices (Wilmington, MA).

The UFS Series direct-analog sources achieve frequency and amplitude switching speeds of better than 200 ns from 0.01 to 40.00 GHz, with frequency resolution as fine as 1 Hz. They also boast low spurious noise and single-sideband (SSB) phase noise of −126 dBc/Hz offset 10 kHz from a 10-GHz carrier. The DS Series of synthesizers switch from 5 MHz to 20.48 GHz with step sizes as small as 1 Hz and as large as 20 MHz. The switching speed is 300 ns for the larger step sizes while the phase noise is a low −120 dBc/Hz offset 10 kHz from a 10-GHz carrier.

The two smaller signal sources include the AD9956 DDS IC, capable of sub-Hertz frequency resolution and 0.22-deg. phase resolution through 2.7 GHz thanks to an on-board 24-b frequency accumulator and a 48-b phase accumulator. The packaged DDS chip can execute multiple chip synchronization and perform linear frequency sweeps with low power consumption. The phase noise is only −125 dBc/Hz offset 1 kHz from the carrier. The fourth signal source product group is the DCFO ad DCMO series of broadband voltage-controlled oscillators (VCOs) from Synergy Microwave (Paterson, NJ). The surface-mount VCOs are available in bands as wide as 350 to 1050 MHz (700 MHz) over a frequency range from 350 to 4200 MHz. Phase noise is only 112 dBc/Hz offset 10 kHz from a carrier in the 350-to-1050-MHz range.

Since all of these signal sources must be tested, the engineers at Agilent Technologies developed the model E5052A Signal Source Analyzer, introduced at the 2004 Microwave Theory & Techniques Symposium (MTT-S) in Fort Worth, TX. The tester handles sources with carrier frequencies from 10 MHz to 7 GHz and checks noise at offsets from 1 Hz to 40 MHz. With noise sensitivity of better than −178 dBc/Hz, the analyzer can test frequency, output power, tuning linearity, phase noise, frequency, phase, and power transients versus frequency, and DC current. With external downconverters, the carrier range can be extended to 110 GHz.

Several other test instruments graced the top products list, with Anritsu's MS2781A also introduced at the Fort Worth MTT-S. The Signature™ analyzer performs frequency- and time-domain analysis on signals captured within a 30-MHz-wide instantaneous bandwidth that can be swept from 100 MHz to 8 GHz. Employing a low-noise 9.5-to-17.5-GHz first-stage local oscillator and four total stages of frequency downconversion, the analyzer essentially combines many aspects of a spectrum analyzer and a vector network analyzer. It can perform frequency-domain sweep as narrow as 1 Hz and time-domain sweeps as narrow as 1 µs at reference amplitude levels from −150 to +30 dBm.

For fans of traditional vector network analyzers, the list includes the ZVM series of instruments from Rohde & Schwarz (Columbia, MD). With two instruments in the family, covering 300 kHz to 4 GHz and 300 kHz to 8 GHz, these instruments provide exceptional dynamic range of 123 dB or more for multiport and balanced (mix-mode) S-parameter measurements. Measurement time is less than 8 ms while trace noise is less than 0.01 dB, for an RF power sweep range of −40 to +13 dBm. The number of display traces is limited only by the amount of on-board instrument random-access memory (RAM).

For power-amplifier designers in need of optimum efficiency, a series of frequency-selective load-pull tuners from Focus Microwaves (Dollard-des-Ormeaux, Quebec, Canada) can create independently controllable impedances at three different frequencies. The tuners simply amplitude and phase tuning at, for example, a fundamental frequency and two harmonics. The tuners, which are available for use from 1.8 to 18.0 GHz, enable amplifier testers to achieve maximum power-added efficiency (PAE) at a given level of linearity.

Several ICs and a multifunction module comprise the remainder of the list. First-time Top Product winner iTerra Communications offered a sample of their engineering ingenuity in broadband circuitry with their model iT-6130 driver/data-converter module (March Cover, p. 108). The module combines a non-return-to-zero (NRZ)/return-to-zero (RZ) converter and high-speed modulator driver for use in high-speed optical communications systems operating to 11.5 Gb/s. Also available as two surface-mount chips, the multifunction unit helps extend the distance between optical amplifiers in long-haul communications systems. Maxim Integrated Circuits rejoined this year's list with their model MAX1211 and MAX1418 high-speed analog-to-digital converters (ADCs). The former provides 12-b resolution at 65 MSamples/s while the latter offers 15-b resolution at 65 MSamples/s. Hittite Microwave Corp. (Chelmsford, MA) added the 0.1-to-4.0-GHz model HMC497LP4 direct quadrature modulator and the model HMC500LP3 1.8-to-2.2-GHz vector modulator to the list. The former features a noise floor of −159 dBc/Hz and +9 dBm output power at 1-dB compression for an outstanding dynamic range while the latter has an input third-order intercept of +33 dBm and input noise floor of −152 dBm at its minimum gain setting (a 40-dB gain control range).

Last, but not least, the Nexxim circuit simulation and verification software from Ansoft Corp. (Pittsburgh, PA) is a time-saving design tool that doesn't sacrifice accuracy for speed. Offering orders of magnitude improvement in capacity, accuracy, and simulation speed, Nexxim is ideal for large, complex circuits and can tackle difficult mixed-signal devices such as ADCs and phase-locked loops (PLLs) with speeds formerly associated with single-transistor circuits.