Microwave Journal
www.microwavejournal.com/articles/26269-gan-improves-efficiency-of-rugged-compact-100-w-ka-band-sspa

GaN Improves Efficiency of Rugged, Compact 100 W Ka-Band SSPA

April 13, 2016

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Teledyne Paradise Datacom has developed a 100 W solid-state power amplifier (SSPA) packaged in a rugged, compact outdoor enclosure. The Compact Outdoor family of SSPAs has a long legacy of providing high reliability in extreme environmental conditions. With an MTBF greater than 100,000 hours, this new Ka-Band SSPA joins that family of products.

The 100 W Ka-Band SSPA is available with several options that include: wideband coverage (27 to 31 GHz) as well as operation over any 1 GHz sub-band in that range when used with an integral L-Band block up-converter (BUC). This HPAA2100 series utilizes the latest GaN technology to achieve 100 W of saturated power at the output flange of the amplifier. The linear output power is one half of the saturated output power, or 50 W, to maintain -26 dBc third-order intermodulation products. Alternately, 50 W linear output power is achieved with a single QPSK or OQPSK signal while maintaining -30 dBc spectral regrowth at 1´the symbol rate. The outstanding linear output power is made possible by embedded analog linearization circuitry.

The gain of the amplifier is 75 dB and is adjustable down to 55 dB in 0.1 dB increments. Gain is temperature compensated so that it does not vary from the set level as the ambient temperature of the amplifier changes; typical gain variation is ±0.5 dB from -30° to +50°C. The operational temperature range of the amplifier is from -40° to +60°C. The amplifier is protected from high VSWR by an integral microwave isolator. An RF sample port provides a -40 dBc sample of the RF output power via a 2.92 mm female connector.

The efficiency of the GaN devices is seen in the overall amplifier efficiency. At its linear output power setting, the amplifier consumes less than 1000 W of AC prime power. The integral AC to DC switch-mode power supply is power factor corrected and operates over an AC input voltage range of 180 to 260 VAC.

The latest 3D electromagnetic (EM) modeling techniques were used to design and optimize spatial waveguide combining networks to achieve the lowest possible insertion loss. This allows efficient combining of multiple, discrete, lower power GaN devices to achieve the higher output power levels. The amplifier chassis has a unique thermal design that uses forced air convection cooling. A removable fan tray on the bottom of the amplifier is easily removed to clean out excessive dirt and debris from the internal heat sink. No special tools are required to remove the fan tray, making maintenance easy to perform in the field.

The L-Band BUC is a popular option that allows operation directly from an L-Band frequency source, up-converting a signal input in the 1000 to 2000 MHz range to Ka-Band.  The BUC has a low phase noise local oscillator that can be supplied with a high stability reference oscillator. With the reference oscillator, the converter can automatically detect and switch to an externally supplied 10 or 50 MHz reference frequency. The low noise phase-locked local oscillator can be set to allow the unit to operate over the 28 to 29 GHz, 29 to 30 GHz or
30 to 31 GHz output frequency bands.

The HPAA2100 series amplifier has the same monitor and control functionality as the other members of the Compact Outdoor amplifier family. The standard interfaces include RS485/422/232, discrete IO and Ethernet. The Ethernet interface can be integrated into higher level monitor and control systems using SNMP or UDP. For simplicity, a built-in web browser enables easy setup from any computer. Built-in redundancy control is a standard feature on all Compact Outdoor SSPAs. This provides control over an external redundancy switch without needing a separate controller. A Windows-based monitor and control program is available for free download from the Teledyne Paradise Datacom website.

Along with its CE label, the HPAA2100 has been tested to stringent MIL-STD-461 EMI standards and MIL-STD-810 environmental standards. Weighing less than 50 lbs. (22.6 kg), this product represents a new standard in power density for Ka-Band SSPAs. This flagship product is the first of a series of Ka-Band SSPAs that will provide up to 500 W of saturated output for the most demanding requirements.

Teledyne Paradise Datacom
State College, Pa.
www.paradisedata.com