Microwave Journal

8 kW X-Band PA Powered by GaN

June 12, 2019

Taking solid-state power to levels formerly captive to tubes, Comtech PST has developed an 8 kW GaN-based power amplifier (PA) for X-Band radar applications. Operating over any 1000 MHz instantaneous bandwidth between 9 and 10.5 GHz, the
BMPC9X89X8-8000 provides 8 kW pulsed peak output power, with pulse widths up to 100 µs and a maximum 10 percent duty cycle. Rise and fall times are less than 25 ns, and pulse droop is typically under 0.15 dB/μs. The gain at rated power is typically 69 dB. Harmonics are no greater than −60 dBc at full output, and the amplifier’s phase noise is −108 dBc/Hz at 100 Hz offset from the carrier. With the RF off, the noise floor drops to −170 dBm/Hz typical.

Input and output VSWR are better than 1.5:1. The input signal is applied via a female SMA connector, and the output interface is through WR112 or WR90 waveguide. Forward and reflected power, 60 dB down, can be sampled through two female SMA connectors. The BMPC9X89X8-8000 has an Ethernet interface and uses differential RS-422 for on/off gate control. The PA has extensive self protection for high load VSWR, duty factor, pulse width and temperature. Packaged for benchtop or rack mounting, the 19 in. x 12.25 in. x 25.78 in. PA has an internal power supply powered with 115 V AC and uses 3.6 kVA maximum. It will operate from 0°C to 50°C, 0 to 95 percent non-condensing humidity and up to 12,000 ft. altitude.

The class AB design uses modular GaN amplifiers that can be combined to achieve custom PAs with output power from 2 to 16 kW. Because of the modular architecture, the output power will degrade gracefully in case of a power module failure.

Comtech PST
Melville, N.Y.