As one of six companies from five European countries involved in designing products for the MAGNUS program – a European Defense Agency project aimed at developing European-sourced application technologies for gallium nitride on silicon (GaN-on-SiC) used in advanced radar, communications and electronic warfare (EW) systems spanning 2-18GHz – aerospace, defense and space contractor Thales UK has designed 10W GaN monolithic microwave integrated circuit (MMIC) power amplifiers based on the 0.25µm foundry process of United Monolithic Semiconductors (UMS). In parallel with this, package design and thermal analysis tasks were also undertaken.
After the MMICs had been fabricated and packaged, they were used to design a demonstrator unit, which Thales UK then leveraged to design a 30W microwave power module (MPM). Two foundry runs were conducted.
The design targeted a frequency range of 6-18GHz, with 10dB gain, and 10W output power. It was decided to use a non-uniform distributed amplifier topology, which is suited to broadband operation because it is inherently stable. The goal was to design two distributed amplifiers on a chip between a pair of splitter/combiner networks. For the first foundry run the amplifiers were combined off chip, and for the second run the combining was done on chip.
The MMIC designs were created using NI AWR’s Design Environment, specifically Microwave Office circuit design software. The passive structures were simulated in AXIEM 3D planar EM simulator, and the package was analyzed in Analyst 3D finite-element method EM simulator.
“Our design and simulation efforts showed that the UMS PDK [process design kit], as well as the Microwave Office and Analyst models, were very accurate, which led to the success of this project,’’ comments Rashid Fazaldin, microwave design engineer at Thales UK.