Critical analysis of results for a european GaN power amplifier after first iteration
ABSTRACT This paper presents the results of the development of 2-6 GHz broadband high-power amplifiers (HPA) within the 1st iteration of the European Korrigan project. The HPAs were fabricated using AlGaN/GaN high electronic mobility transistors (HEMT) and monolithic microwave integrated circuit (MMIC) technology. Two microstrip HPAs with output-stage active periphery of 4 mm and 8 mm are reported. The two-stage amplifiers were designed to be fully matched to 50 Omega input and output impedances. Based on a 0.5 mum gate-length microstrip HEMT technology, the MMICs were fabricated on a 70 mum thick SiC substrate. Under a 25 V DC bias condition the broadband amplifiers have exhibited about 18 dB small-signal gain. The 4mm-HPA delivers 10 W output power and 25% power added efficiency (PAE) in the 2-6 GHz frequency band, in continuous wave operation (CW) at Vds=25V. On the other hand, the 8mm-HPA delivers 16 W and 20% PAE in CW. In pulsed-mode, the output powers are 14 W and 25 W for the 4 mm and the 8 mm HPAs, respectively.
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ABSTRACT: This paper describes a C-band monolithic high power amplifier implemented with a 0.25 μm AlGaN/GaN HEMT process. The circuit has been designed for use in synthetic aperture radar antenna modules in space applications. The amplifier is made up of two stages: the final stage consists of eight devices for 9.6 mm of total periphery that are merged together to form a single power-bar. A quasi-inverse class-F regime for the HEMTs is implemented by harmonic tuning in order to achieve the best tradeoff between maximum output power and efficiency. When operating in pulsed mode with 50 μs pulse width and 10% duty cycle, the amplifier delivers about 40 watt with 21 dB of associated gain and 40% PAE over a 15% bandwidth centered at 5.4 GHz. The proposed MMIC HPA is a very valuable replacement for lower output power MMIC GaAs HPAs or hybrid HPAs, which are currently exploited at C-band for these applications.Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International; 01/2013
Article: A C-Band AlGaN-GaN MMIC HPA for SAR[Show abstract] [Hide abstract]
ABSTRACT: A C-Band MMIC high power amplifier (HPA) has been designed exploiting a 0.25 mu m HEMT GaN process on SiC substrate. The HPA is designed for future synthetic aperture radar (SAR) antenna applications. The HPA delivers 16 W output power with PAE over 38% at 6 dB gain compression within a 900 MHz bandwidth around 5.75 GHz. Up to 20 W output power and 40% PAE are obtained at higher gain compression. A comparison with another amplifier, differing only for the layout of the devices in the final stage, points out that the transistor thermal conditions represent the main limitation for this high power density technology.IEEE Microwave and Wireless Components Letters 09/2012; 22(9-9):471-473. DOI:10.1109/LMWC.2012.2212238 · 2.24 Impact Factor
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ABSTRACT: Two C-band monolithic high power amplifiers (HPAs) have been designed and implemented exploiting a 0.25-mu m AlGaN/GaN HEMT process on an SiC substrate. The circuits have been designed for use in transmit/recevie modules of satellite synthetic aperture radar antennas for Earth observation. The design was accurately focused on the HEMTs' electrical and thermal working conditions in order to guarantee the reliable operation required by space applications. The HPAs operate in pulsed conditions with typical pulsewidth of 50 mu s and 10% duty cycle: in that regime, the circuits deliver about 40 W with more than 21-dB associated gain and 40% to 45% power-added efficiency in the 5-5.8-GHz band. The achieved performance clearly demonstrates the very high potentiality of this technology for the replacement of GaAs-based HPAs in new generations of this type of systems.IEEE Transactions on Microwave Theory and Techniques 12/2013; 61(12-12):4492-4504. DOI:10.1109/TMTT.2013.2286109 · 2.94 Impact Factor