Earth observation and Climate research
Due to Climate change within last decades this topic became extremely important. Earth Climate is researched by several possible approaches:
Ground-based
as an example here are cloud radars. These can determine speed of wind and cloud density, allowing for Climate investigation and prediction of local weather. Such radars usually use FMCW-radars but require very high-power of the transmitter at mm-waves and a sensitive coherent receiver.
ACST offers high-power transmitter front ends in for of AMC-s and heterodyne receivers in form of MixAMC-s for this technology. Various WG Components are always required for customized system assembly. Moreover, ACST offers a service for development customized functional modules and sub-systems based on ACST high-power multiplier technology and film-diode technology, both aiming at ultimate performance at mm-waves and THz frequencies.
Airplane based
as an example here is NASA/ESA/DLR SOPHIA project, which placed mm-wave/THz radiometers on an airplane. This approach allows investigation of Earth atmosphere in the height of up to 20km. These instruments usually use passive radiometers in mm-wave and THz frequency range. A passive radiometer at THz frequencies usually uses a high-sensitive heterodyne receiver, which, however, requires a powerful Local Oscillator (LO) for optimal operation. ACST offers LO-sources in form of AMC-s and heterodyne receivers up to THz frequencies as MixAMC-s but also service for development of dedicated Receivers at frequencies up to 1.5THz and beyond. Various WG Components are always required for customized system assembly.
Balloons
Helium-filled balloons can bring mm-wave/THz instruments to the height of several tens of km above the Earth surface to allow for investigation of upper layers of Earth atmosphere. Similarly to Airplane-based, these instruments also typically use passive radiometers. Like the item above, ACST can offer service for development of dedicated Transmitters and Receivers at frequencies up to 1.5THz and beyond.
Space satellites
Several Space Agencies, like ESA and NASA are running space missions for Earth observation and Climate research based on space satellites. This approach allows for investigation of dynamics of Climate processes on Earth surface and atmosphere on large surfaces. Obtained results are of great importance for Climate research but also for weather forecast. Satellite-based instruments are usually using highly sensitive passive receivers. These may be either direct-detection radiometers or heterodyne based radiometers. Direct detection radiometers are preferred for use on a satellite because of low complexity, low weight, and low power consumption. However, this technology requires Low Noise Amplifiers (LNA) in the receiver front-end. Current LNA technology is limited in frequency to mm-waves. Therefore, for sub-mm-wave and THz frequencies heterodyne receivers must be employed.
With more than 15 space-related R&D projects within last 15 years ACST became a strong partner in development mm-wave /THz components, functional modules, and systems for aero-space applications. ACST has been involved in several space missions for Earth observation and climate research. Among them are ESA space missions MetOp-SG and AWS. ACST provides Schottky diodes for several frequency channels, including the ever-highest frequency instrument among space-based instruments ICI. Apart of Schottky diode components, ACST supplies recognized best detector worldwide for 89GHz direct detection radiometer for ESA MetO-SG space mission. In another ESA space mission called AWS. ACST supplies the whole 89GHz receiver system.
ACST is ready for collaboration in future missions for planetary research and climate control by providing service for development, manufacturing, and qualification of components, functional modules, and sub/systems at mm-waves and THz frequencies.
