Trends and challenges in mmwave/THz systems for sensing, space and communication
Electromagnetic waves in the atmosphere feature maximum transmission in the frequency bands around 94, 140, 220, 340, 410, 480, 660, and 850 GHz, predestining them for millimeter-wave high-speed data links and long-distance, high-resolution radar and imaging systems. High operating frequencies allow for precise geometrical resolution due to high absolute bandwidth and small wavelength, simultaneously reducing the size of components and antennas, a prerequisite for lightweight space-borne and air-borne systems. In comparison to visible/infrared radiation, a particular benefit of mmwave applications is the penetration of dust, fog, rain, snow, and textiles for imaging and sensing.
This talk covers a variety of MMICs and modules developed at the Fraunhofer IAF for manifold applications in the frequency range up to 1 THz, exploiting the advanced MHEMT (metamorphic high electron mobility transistor) technology based on the InGaAs/InAlAs material system. To enable highest operating frequencies, the transit frequency of transistors was boosted to over 600 GHz by utilizing up to 100 per cent indium content in the MHEMT channel and a gate length down to 20 nm. These MMICs represent key components in wireless communication systems (satellite and mobile communication links), sensor systems (atmospheric sensors, non-destructive materials testing, collision avoidance radar), as well as radio astronomic receivers (cryogenic ultra-low-noise amplifiers).
A variety of high-performance MMICs, such as ultra-low-noise amplifiers, mixers, oscillators, frequency multipliers, transmitters, receivers, as well as complete transmit/receive and radar circuits will be presented, as well as different approaches for module packaging and system realization. As an example, transmitter and receiver chip sets for high-speed data links and active imaging systems up to 350 GHz will be discussed.