Broadband microwave amplification is vital to a large number of defense-related systems, including in communications, direction-finding (DF), radar, and electronic-warfare (EW) systems. Although large traveling-wave-tube amplifiers (TWTAs) have often been used to boost signal levels in these systems, wide-bandgap transistor technologies such as gallium nitride (GaN) have been gaining in power and frequency in recent years, making possible true TWTA-replacement amplifiers based on solid-state devices. CTT, Inc. has developed a line of durable GaN-based amplifiers capable of pulsed and continuous-wave (CW) power levels to 40 W at the frequencies most commonly used in defense systems, from 2 to 18 GHz (see figure).

The broadband amplifiers draw upon CTT’s long experience in microwave-integrated-circuit (MIC) thin-film technology for high reliability, even within the rigorous environments faced by aerospace/defense electronic systems. They are designed for operating temperatures from −55 to +85°C and also incorporate automatic thermal-shut-down circuitry to protect against overheating. Units are available for full coverage of the 2-to-18-GHz frequency range or portions thereof. The table offers a sampling of some standard available models. In addition, custom designs are available upon request.

For example, model AGM/060-4343 is designed for use from 2 to 6 GHz. It delivers +43 dBm typical saturated output power across that band, even at the band edges, in pulsed or CW operation. It boosts input signals with 43-dB minimum gain while achieving ±2.5 dB gain flatness across the 4-GHz operating bandwidth. Its maximum noise figure is 6 dB and maximum VSWR is 2.0:1. The amplifier’s GaN devices draw 1820 mA current from a +30-VDC supply under small-signal conditions and 4200 mA current from a +30-VDC supply when operating at saturated output-power levels.

When more gain is needed for that same 2-to-6-GHz bandwidth, the firm also offers the model AGM/060-4646 GaN amplifier, with 46 dB minimum gain and ±2.5 dB gain flatness from 2 to 6 GHz. This amplifier also provides greater output power, with +46-dBm typical saturated output power across the operating band and +45.5-dBm minimum saturated output power at the band edges. It has a maximum noise figure of 6 dB and maximum input/output VSWR of 2.0:1. The AGM/060-4646 draws 3420 mA current from a +30-VDC supply under small-signal conditions and 770 mA current from the same supply when operating at saturated output-power levels.

For truly broadband applications, the model AGX/0218-3946 GaN power amplifier boasts 46-dB minimum gain with ±3.0-dB gain flatness from 2 to 18 GHz. It generates +39-dBm typical saturated output power across that frequency range with +38-dBm minimum saturated output power at the band edges. It exhibits 8-dB maximum noise figure from 2 to 18 GHz with maximum input/output VSWR of 2.20:1. It consumes 1350 mA from a +32-VDC supply at small-signal conditions and 3100 mA from a +32-VDC supply when providing full saturated output-power levels.

The highest-gain unit in the GaN PA line is model AGM/180-4458, with 58-dB minimum gain and ±2.5 dB gain flatness from 6 to 18 GHz. It has a maximum noise figure of 7 dB across that frequency range, with maximum input/output VSWR of 2.0:1, and provides +44-dBm typical saturated output power and +43-dBm minimum saturated output power at the band edges. This amplifier consumes 4100 mA current from a +32-VDC supply under small-signal conditions and 8600 mA current from the same voltage supply when operating at saturated output-power levels.

CTT, Inc.
241 East Java Dr.
Sunnyvale, CA 94089
(408) 541-0794
FAX: (408) 541-0596