Blythe C. Deckman

A 5-watt, 37-GHz monolithic grid amplifier

A 5-Watt Ka-band amplifier has been demonstrated. The area of the grid amplifier is 1 cm/sup 2/ and there are 512 transistors. The small-signal gain of the grid is 8 dB at 37.2 GHz, with 1.3 GHz bandwidth. At 5 Watts output, the gain is 5 dB with 15% power-added efficiency. An aluminum-nitride heat spreader allows continuous operation with an estimated gate temperature of 70/spl deg/C.

A Ka-band grid amplifier module with over 10 Watts output power

We present a Ka-band grid amplifier power module. The module is fully packaged with waveguide input and output flanges. It includes a driver grid amplifier chip for gain, followed by a booster grid amplifier chip for power. With a 50/spl deg/C baseplate temperature, the module has a small signal gain of 12 dB. The single-chip output booster stage delivers over 16 Watts of saturated power. The module delivers over 10 Watts output with a constant 1.6 Watts input over a 550 MHz bandwidth. We also present a large-signal third-order intermodulation and AM/PM conversion measurements, which are consistent with expectations. To our knowledge, this is the highest power ever reported from a monolithic single-chip power amplifier at Ka-band.

Design and Performance of a 600-W

This paper describes the design and performance of a C-band amplifier with over 600 W of saturated output power. This amplifier is intended for use in commercial broadcast satellite uplink base stations. The amplifier uses spatial power combining to combine the output powers of sixteen internally matched 45-W GaAs FETs. The amplifier also comprises pre-amplification and driver amplification stages, a level control variable attenuator, and a predistortion linearizer. The unit also includes a power supply as well as a user monitor and control interface. We will present various measures of this amplifiers linearity performance, demonstrating its suitability for use in broadcast applications. Finally, we will present results from power combining two of these amplifiers, resulting in a solid-state amplifier with 1.4 kW of saturated C-band output power.

C

By spatially combining the outputs of many solid-state devices on a single chip, grid amplifiers are not only powerful, linear, and efficient, but also are compact, rugged, and robust. We present measured data from a fully-packaged Ka-band module with standard waveguide input and output flanges. With a 50/spl deg/C baseplate temperature, the module can be biased to deliver from 10 to 16 Watts of rated output power in the 30-31 GHz band. The module exhibits very good spectral regrowth performance, and can be operated well into saturation in single-carrier terminals for shared-spectrum multiple-access applications.

-Band Amplifier Using Spatially Combined GaAs FETs for Satellite Communications

This paper describes the design and performance of a C-band amplifier with over 600 Watts of saturated output power. This amplifier is intended for use in commercial broadcast satellite uplink base stations. The amplifier uses spatial power combining to combine the output powers of sixteen internally matched 45-W GaAs FETs. The amplifier also comprises pre-amplification and driver amplification stages, a level control variable attenuator, and a predistortion linearizer. The unit also includes a power supply as well as a user monitor and control interface. We will present various measures of this amplifiers linearity performance, demonstrating its suitability for use in broadcast applications.

Power and spectral regrowth performance of 10-W and 16-W Ka-band power amplifiers with single-chip output stages

This paper presents the design and performance of an X-band GaAs FET power amplifier (PA) system with 100-W of saturated output power. A simple and cost-effective predistortion linearizer is developed to increase the linear output power of the PA system. To spatially combine output powers of GaAs FETs and to launch output signals directly into the WR-112 waveguide, the PA uses a pair of microstrip-to-coaxial transition probes. Measurement shows that linearization significantly reduces the PAs nonlinear signal distortions, resulting in a 3 dB increase of operating linear output power.

A 600-W C-Band Amplifier Using Spatially Combined GaAs FETs

This paper describes the use of focused Gaussian beams in making quasi-optical measurements at Ka-band. Measurement results for a known standard are presented to validate the measurement technique. Measurement are presented both for the case in which the beam waist is smaller than the quasi-optical array under test and in which the beam waist is slightly larger than the array. The measurements are compared with simulations of infinite arrays illuminated by plane waves. Good agreement can be found between measurement and simulation, provided appropriate calibrations are performed and certain precautions observed. This paper describes a newly developed calibration technique that can be applied when the size of the array under test is comparable to or slightly smaller than the beam waist.