Advanced RF sensors for SAR earth observation using high precision T/R-Modules

Radar sensors are of increasing importance for all kind of scientific, commercial and security related tasks. Modern AESA (Active Electronically Scanned Array) Radars and their related operational benefits use as Key Technology T/R Modules to form the Antenna Aperture. This paper will discuss design issues, main features and measured performance of a T/R-Module for Synthetic Aperture Radar. The applied internal temperature drift compensation over a wide temperature range as well as low noise amplification during receive operation are key features of the module including polarization agility and high gain - and phase accuracy. The module is a qualified product and in orbit since 2007 without sound performance lacking any failure or degradation. The so called `Standardized Modular T/R-Module´ (SMTR-Module) forms the core unit together with two further physical building blocks `Front-end Electronics Unit´ and `Control Electronics´, all of them assembled in a common housing. The Built Standard of the Module based on qualified processes and the Module´s Technology itself were derived by a more than twenty years of effort now leading to powerful cutting edge and competitive products. Current applications are not only in Space like TerraSAR-X or TanDEM-X (Space), but also Tactical Ground Based Systems (BÜR) or Air Defense (NATO-MEADS) Systems, or Airborne based Fighter e-scan Antenna demonstrators (CAESAR). C-Band, X-Band and Ku-Band are applicable frequencies for these products combining High Quality up to space level grades and quantities up to some 50k Modules were built. Besides the results out of the successful Mission TerraSAR-X and TanDEM-X, future designs and the use of advanced technologies, like GaN, will improve operational performance even further, e.g. bandwidth, power, efficiency. The planned missions require high resolution designs and short revisit times resulting in Wide Band designs even at a Reasonable Cost level.