GaN And GaAs Microwave Transistors And Amps Extend Power And Frequency Range

July 7, 2010
New HEMT and FET devices target satellite and microwave RF power applications.

Power amplifier

Satellite communications

5.65- to 8.50-GHz

Toshiba America Electronic Components Inc. has introduced several new devices that are ideal for satellite and other microwave radio applications. These applications include fixed and broadband wireless access (FWA/BWA) systems such as WiMAX, point-to-point (PTP) or point-to-multi-point (PTMP) terrestrial microwave radio links, satellite communications systems like high-power solid-state power amplifiers (SSPA), very small-aperture terminals (VSATs), radar systems, and some industrial uses.

One of the more interesting devices is a 50-W gallium nitride (GaN) semiconductor high electron mobility transistor (HEMT) power amplifier (Fig. 1). Designated the TGI7785-50L, it operates in the 7.7- to 8.5-GHz range. RF performance specifications include an output power of 47.0 dBm (typical) with 40-dBm input power, typical linear gain of 11.0 dB, and drain current of 5.0 A at 24 V. The TGI7785-50L also boosts output power and helps reduce size and weight in solid-state power amplifiers (SSPAs) for satellite communications applications. Samples of the TGI7785-50L are available now, with mass production scheduled for the third quarter.

Next, the Ku-band TGI1414-50L gallium-nitride (GaN) power amplifier operates in the 14.0- to 14.5-GHz range for satellite communications applications. GaN technology provides superior device performance such as high gain and efficiency in the satellite communications and radar markets. Toshiba expects to develop additional GaN devices in the C, Ku, and other bands with even higher output power.

The company also is expanding its Ku-band gallium-arsenide field-effect transistor (GaAs FETs) lineup with two devices with higher output power rated for 18 and 30 W. The TIM1213-18L and TIM1213-30L operate in the 12.7- to 13.2-GHz Ku band and target use in microwave radios for microwave links and satellite communications (Fig. 2). Other current Toshiba GaAs FETs in this frequency range feature 2-, 4-, 8-, 10-, and 15-W power output ratings.

The TIM1213-18L has output power at a 1-dB gain compression point (P1dB) of 42.5 dBm, power gain at a 1-dB gain compression point (G1dB) of 6.0 dB, and 28% power efficiency. The TIM1213-30L features a P1dB of 45.0 dBm (typical), G1dB of 5.5 dB (typical), and power-added efficiency of 23%. Samples of both are available now.

The 4-W C-band gallium-arsenide (GaAs) TMD0608-4 monolithic microwave integrated circuit (MMIC) suits satellite applications. It operates in the 5.65- to 8.50-GHz range (Fig. 3). With this broad bandwidth, a high gain of 27 dB throughout the operating range, and 50-Ω internal matching, the device is well suited for use as a pre-amplifier in C-band satellite and terrestrial communications. Its output power at a 1-dB gain compression point (P1dB) is 35.5 dBm (typical), with a power gain at a 1-dB gain compression point (G1dB) of 27 dB (typical). The MMIC is housed in a hermetically sealed package as well.

“The use of a broad-band, internally matched amplifier can reduce the varieties of board design for different C-band requirements, save board space by minimizing the number of discrete amplification stages, and increase design reliability due to a reduced part count,” says Homayoun Ghani, business development manager of Toshiba’s microwave, logic, and small signal devices.  

Samples of the Toshiba TMD0608-4 MMIC will be available in the third quarter.

Toshiba America Electronic Components Inc.

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