A 6–18 GHz high-power amplifier (HPA) design in GaN on SiC technology is presented. This power amplifier consists of a two-stage corporate amplifier with two and four transistors, respectively. It has been fabricated on UMS using their 0.25 µm gate length process, GH25. A study of the suitable attachment method and measurement on wafer and on jig are detailed. This HPA exhibits an averaged output power of 39.2 dBm with a mean gain of 11 dB in saturation and a 24.5% maximum power added efficiency in pulse mode operation with a duty cycle of 10% with a 25 µs pulse width.

In order to perform an accurate design, in particular in non-linear circuit, the equivalent circuit of inductors must be precisely described in a wide frequency band. Many models have been proposed to describe the behavior of inductors on lossy substrate. They consist of a great number of elements, often suggested by physical phenomena. Most of them cannot be extracted from measurements. In this paper, we propose a model composed only of elements that can be analytically extracted from measurement results.

Different wideband amplifiers, hybrid designs at lower frequencies, and monolithically integrated circuits (MMIC) at higher frequencies were designed, fabricated, and measured. These amplifiers are all based on AlGaN/GaN HEMT technology. The future applications for these types of amplifiers are mainly electronic warfare (EW) applications. Novel communication jammers and especially active electronically scanned array EW systems have a high demand for wideband high power amplifiers. The second application also needs high robust low noise amplifiers for its receive path. Output power levels of 38 W for hybrid amplifiers at lower frequencies up to 6 GHz and 15 W for the MMIC power amplifiers at higher frequencies are measured. With these building blocks, novel EW system approaches can be investigated.

Amplifiers for the next generation of T/R modules in future active array antennas are realized as monolithically integrated circuits (MMIC) on the basis of novel AlGaN/GaN (is a chemical material description) high electron mobility transistor (HEMT) structures. Both low-noise and power amplifiers are designed for X-band frequencies. The MMICs are designed, simulated, and fabricated using a novel via-hole microstrip technology. Output power levels of 6.8 W (38 dBm) for the driver amplifier (DA) and 20 W (43 dBm) for the high-power amplifier (HPA) are measured. The measured noise figure of the low-noise amplifier (LNA) is in the range of 1.5 dB. A T/R-module front-end with mounted GaN MMICs is designed based on a multi-layer low-temperature cofired ceramic technology (LTCC).

Low-cost enabling technologies for T/R modules (TRMs) in phased array radars are proposed and analyzed in terms of technology, performance, and cost aspects. Phase and amplitude controlling integrated circuits (ICs) realized in a low-cost standard silicon process are demonstrated. The design of several ICs at the S-, C-, on X-band has shown that silicon germanium is a strong contender for gallium arsenide. This also applies to TRMs suited for military active phased array antenna (AESA) radars. The circuits presented in this paper are manufactured by austriamicrosystems in their 0.35 µm SiGe-BiCMOS process with an fT of around 70 GHz. A TRM packaging concept based on soldered surface-mount technology and organic substrates is also demonstrated. A cost analysis concludes that by using the proposed packaging concept and the SiGe core-chip technology, the TRM production cost can be potentially reduced by 70% compared to traditional ceramic hermetic packaging with core chip in GaAs technology.

Significant progress has been made in the development of SiC metal semiconductor field-effect transistors (MESFETs) and monolithic microwave integrated-circuit (MMIC) power amplifiers for high-frequency power applications. Three-inch-diameter high-purity semi-insulating 4H-SiC substrates have been used in this development, enabling high-volume fabrication with improved performance by minimizing surface- and substrate-related trapping issues previously observed in MESFETs. These devices exhibit excellent reliability characteristics, with mean time to failure in excess of 500 h at a junction temperature of 410°C. A sampling of these devices has also been running for over 5000 h in an rf high-temperature operating-life test, with negligible changes in performance. High-power SiC MMIC amplifiers have also been demonstrated with excellent yield and repeatability. These MMIC amplifiers show power performance characteristics not previously available with conventional GaAs technology. These developments have led to the commercial availability of SiC rf power MESFETs and to the release of a foundry process for MMIC fabrication.