Ku-band MMIC Power Amplifiers Developed Using MSAG MESFET Technology

This article presents the design approach and test results of 1, 1.5, 2 and 5 W, Ku-band MMIC power amplifiers developed using the high performance MSAG MESFET technology. Both single-ended and balanced topologies were used. A minimum power-added efficiency (PAE) of 27 percent, an output power (Pout) of 5 W and an associated gain of 21.5 dB were achieved over the 12.5 to 14.5 GHz frequency range. To the author’s best knowledge, these results represent the state-of-the-art in MESFET-based MMIC Ku-band power amplifiers.

During the past decade, there has been significant progress in monolithic Ku-band power amplifiers operating over both narrow and broad bands. Many different technologies, including MESFET, HBT and HEMT, are being pursued to develop MMIC power amplifiers1–6 in order to obtain the maximum output power (Pout) and power-added efficiency (PAE) from a single chip. Progress in this area, for Ku-band MMIC power amplifiers, has been summarized in Table 1. The performance listed is the minimum over the frequency range. MMICs with greater than 1 W output power were selected for comparison. The gain shown is taken at the minimum power level. Although MIC technology can be used to develop broadband power amplifiers, power MMIC amplifiers, in general, offer smaller size and lightweight, higher gain, wider bandwidth, higher reliability, lower cost and much better unit-to-unit amplitude and phase tracking capability, when manufactured in large volume. MMIC power amplifiers have the following potential advantages as compared to commonly available internally matched power amplifiers: