KERAMIS is the acronym of a German research and development project funded by the German Space Agency (DLR) and the Federal Ministry of Economics and Technology (BMWI). The consortium is developing an RF circuit technology for Ka band multimedia satellite applications. A set of modules has been designed, manufactured, and tested by the partners of the consortium. The goal of this effort is to qualify the KERAMIS technology for space applications and to participate in an on-orbit-verification (OOV) program of the DLR. The launch of the technology verification satellite (TET) is scheduled for late 2010. This paper will give an overview of innovative circuit and module designs as well as the assembly, integration, and test results of the project. The authors will present a modular circuit concept for state-of-the-art transmitters and receivers in space at around 20 GHz. Selected modules are a 4 × 4 switch matrix, two synthesizers, and other RF modules. All circuits are based on multilayer ceramic (LTCC) including passive components, transitions, housings, and DC supply.
Moving targets induce unique micro-Doppler signatures. After conducting several measurements with human, vehicle, UAV and animal as targets using a 24 GHz radar, the micro-Doppler signatures are observed through time-velocity diagrams. A simple set of micro-Doppler features are then selected and extracted from the measurement data. Results show the potential of radar as a ground surveillance applications, which can operate under wide range of weather and lighting conditions with high privacy standards and low false alarm rate. This paper also indicates that with I/Q modulation in radar, the direction of the target's motion can be preserved, thus provides a more detailed description of the measured moving target.
Conventional communications satellites operate with fixed frequency, polarisation and coverage plans that are drawn up years before their launch during the payload definition phase. The satellite will typically be designed for a lifetime of more than fifteen years. During this operating period, changes in bandwidth requirements and the distribution of the service across its geographic coverage are more than likely. A new generation of communication satellites is expected to respond flexibly to these regional and temporal fluctuations in demand. The concept of cellular division of the coverage area and the coverage of these cells with spot beams in connection with the reuse of frequency bands enables this flexibility. The satellite's frequency plan has to be redefined throughout the mission lifetime via commands from the ground. The Flexible Down-Converter DOCON is one of the new components that allow satellite signals to be redistributed between service areas to flexibly reallocate the most critical spectrum resources as needed. DOCON is a flexible Ka-band down-converter from RF = 27.5 ... 30.0 GHz to IF = 17.7 ... 20.2 GHz designed for GEO communication satellites. The device includes the housing, DC-, RF-, and telemetry / tele-command interfaces. An Engineering Model (EM) in form, fit and function was successfully built and tested. The next stage, the Engineering Qualification Model (EQM), is currently in fabrication and will be qualified until end of 2019. The modular concept comprises hermetically sealed LTCC microwave modules as key building blocks. There are three of these LTCC-modules: the Local Oscillator Module (LOM), the Mixer Module (MXM), and the Variable Gain Module (VGM). Their function and realization shall be discussed in this paper.
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