Millimeter Wave, Low Noise Amplifier

To meet the growing demands to transfer data for intelligence, surveillance and reconnaissance (ISR), Air Force is working on a project to expand MILSATCOM bands with new up-link bands allocated near 51 and 86 GHz. Hittite Microwave Corporation has beeninvolved in development of millimeter wave (MMW) MMICs for many years and introduced novel products for amplifiers, converters, and sources using GaAs PHEMT technology. Recent advances in the semiconductor technology have brought the indium-phosphide(InP) MHEMT (metamorphic high electron mobility transistor) technology to the forefront as the promising technology for the next generation of MMW MMICs. A recent survey of technologies available for MMW low-noise amplifiers (LNA), for example, showedthat LNAs made of MHEMT process have lower noise figure and consume a fraction of the prime power compared to GaAs devices. The reduced power consumption is a critical factor in space-borne platforms with limited prime power resources. This proposaladdresses the prospect of expanding capabilities of LNAs to cover the full range of millimeter wave frequency bands for the projected MILSATCOM applications. LNAs operating over a wide band would provide the flexibility of multi-band operation of futurecommunication links. The proposed program will lead to development of MMW LNAs operating at satellite up-link frequencies of 30 GHz, 44 GHz, 51 GHz, and ultimately at 86 GHz. As an example a 49-52 GHz 2-stage LNA design presented in this proposalexhibits a gain of 12 dB, a noise figure of 1.8 dB, a return loss of 10 dB achieved with only 6 mW of DC power dissipation. These LNAs offer significant advantages over the current industry standards and will impact the market for LNAs in both militaryand commercial communications terminals. The MHEMT technology is the most promising technology for millimeter wave RF LNAs. The low-noise and low-power capabilities of MHEMT will have an impact of replacing GaAs devices in all MMW systems that includecommercial radios, satellite receivers, and sensors. The LNAs will have applications in commercial VSAT/USAT receivers operating in the frequency bands between 30 and 100 GHz.