RF/microwave amplifier technology continues to break new ground, as components suppliers continue to introduce new products to their amplifier product lines. These new amplifiers include low-noise amplifiers (LNAs) with extremely low noise figures, highly efficient power amplifiers (PAs), and more, each designed for various markets. The markets covered include commercial cellular, defense, satellite-communications (satcom), and others.

Gallium nitride (GaN) semiconductor technology continues to make news, as components suppliers are taking advantage of its benefits to deliver amplifiers reaching new levels of performance. Although the market for GaN is largely defense, opportunities in wireless infrastructure and other markets are growing fast.

TriQuint Semiconductor recently announced its new GaN amplifiers, offering performance, size, and durability advantages for communications, radar, and defense RF systems. In addition, the firm recently announced two new GaN processes.

TriQuint now offers the TQGaN25HV process, which is a high-voltage variant of its original quarter-micron GaN process. This new process extends the drain operating voltage of 0.25-μm  GaN transistors to 48 V, while delivering a higher breakdown voltage, greater power density, and high gain for applications from DC to 10 GHz. This enables more rugged devices that can withstand voltage standing wave ratio (VSWR) mismatches, while delivering more RF output power. With its third process, TQGaN15, TriQuint is taking GaN technology to new frequency limits. This new process extends the frequency range of GaN to 40 GHz, while delivering excellent high power density and low-noise performance. The TGA2594 and TGA2595 ground terminal PAs were both created with this new process, providing up to 35 percent power-added efficiency (PAE) in a significantly smaller amplifier size than comparable gallium arsenide (GaAs) solutions.

Among the new portfolio of GaN products is the model TAT9988 MMIC amplifier for cable-television (CATV) and fiber-to-the-home (FTTH) optic networks. The TAT9988 is an industry leader in performance due to its gain, composite distortion, and surface-mount convenience. The TAT9988 exceeds the output linearity performance of traditional GaAs based amplifiers.

TriQuint also unveiled its patented Spatium Technology, which leverages TriQuint’s position as a GaN pioneer and expands its expertise in high power RF solid-state amplifier systems. This technology delivers a higher standard of efficiency, reliability, and frequency range for high-power RF applications, including communications, electronic warfare (EW), and radar. This RF power combining technology replaces traveling-wave-tube amplifiers (TWTAs) in many applications, improving PAE by means of patented coaxial spatial combining techniques. Spatium provides smaller form factors, reduced weight, and higher power densities compared with TWTA based systems or conventional planar power combining products. “TriQuint continues to address our customers’ next generation requirements by delivering innovative high performance RF solutions," explains James L. Klein, Vice President and General Manager for Infrastructure and Defense Products. He adds: "TriQuint innovation is shaping the future for system performance and cost reductions."

NuWaves Engineering recently introduced the latest addition to its NuPower product line of small, lightweight, and efficient RF PA modules. This new S- & C-Band PA, model NW-SSPA-15W-2.5-6.0, provides 15 W minimum saturated output power from 2.5 to 6 GHz (Fig. 1). This PA, which the company calls its most innovative product to date, is based on the latest GaN technology. Its high efficiency makes it the most efficient PA in its class, and with its diminutive 3.15 cubic-inch form factor, the PA is the smallest of its kind on the market, and is ideal for size, weight, and power-constrained applications. The PA is intended for use in applications such as unmanned aircraft systems (UAS), broadband RF telemetry, RF communications systems, software-defined-radios (SDRs), and test labs.

Gallium Nitride Drives Power Amplifier Performance, Fig. 1

Model NW-LBSSPA-10W-2.2-2.5 was also recently announced, which is NuWaves latest entry to its NuPower Xtender series of bidirectional amplifiers. Based on the NuPower product line, this S-Band PA module is designed for use with half-duplex RF transceivers operating amplitude-modulated waveforms such as orthogonal frequency division multiplexing (OFDM) and quadrature-amplitude-modulation (QAM). The NW-LBSSPA-10W-2.2-2.5 is the first linearized model to come from the company's new Xtender series of bidirectional PAs. The PA provides 6 W average output power with a 10 dB peak-to-average power ratio (PAPR) waveform from 2.2 GHz to 2.5 GHz.

New Achievements In LNA Performance

Skyworks Solutions recently unveiled its new portfolio of LNAs, with impressive noise-figure performance.  These newest LNAs are ideal for today's 4G wireless infrastructure as well as markets such as Global Positioning System (GPS), broadband, military, and satcom.

Model SKY67151-396LF is a high performance LNA based on GaAs pseudomorphic-high-electron-mobility-transistor (pHEMT) technology. The LNA operates over the frequency range from 0.7 to 3.8 GHz with a noise figure as low as 0.25 dB. "The advanced 0.25 μm GaAs pHEMT enhancement -mode process provides broadband return loss, high gain, very low noise, and high amplifier linearity," explains Stephen Moreschi of Skyworks. The LNA's internal active bias circuitry provides stable performance over temperature and process variation. The SKY67151-396LF is well suited for macro and micro cellular base stations, repeaters, remote radio heads, tower mounted amplifiers, L- and S-Band military communications, GPS receivers, and proprietary radio networks. Skyworks also plans to release new LNAs by November 2013, which will build upon the SKY67151-396LF as some of the most robust LNAs in the industry today, with extended excellent performance down to very low frequencies.

TriQuint also recently introduced two new GaN LNAs, models TGA2611 and TGA2612, which deliver unmatched power handling and low-noise. The TGA2611 operates from 2 to 6 GHz with 25 dB gain and better  than 1-dB noise figure, while the TGA2612 operates from 6 to 12 GHz with 25 dB gain and 1.5-dB noise figure. The TGA2611 and TGA2612 both provide +25 dBm output power at 1-dB compression (P1dB).