No abstract

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.

Low Temperature Cofired Ceramics (LTCC) technology is increasingly used for creating high-rel solutions, especially in class S products deployed in space. Current research, executed by the german and european space agencies, focuses inter alia on new, compact beam forming networks for Ka-band multiple feed per beam antennas. These networks consist of a high number of dividers and must provide a high isolation between neighbouring cells to ensure compliance with frequency plan regulations. While the LTCC process brings a number of advantages, its thick film printing process and the tolerances of available resistive paste systems introduce difficulties in implementing typical Wilkinson divider networks. This paper presents a novel concept to implement tolerance-optimized dividers, taking special focus on the properties of the LTCC process.

Low-Temperature Co-fired Ceramic (LTCC) is a well-established technology for microwave space products and RF structures and it is a good candidate for these new frequency bands. Embedded passives are available to increase the density of integration even more. At higher frequencies, structures become smaller and more prone to process tolerances. This challenge is addressed here with two novel mm-wave tolerance-optimized RF concepts in LTCC: load termination and Gysel power splitter. The concept presented here minimizes the effect of fabrication tolerances to provide stable RF response.

The complexity of today's satellite systems is ever-growing and system weight and size of the subcomponents are becoming even more critical as the number of channels increases. A possible solution for achieving small systems, while maintaining reliability, is the use of the LTCC process. The so-called Keramis technology is a modular concept, where a number of small, hermetically sealed LTCC modules are connected on a carrier substrate. For these systems, the interconnect technology that connects the different LTCCs is of high importance. This paper presents a novel BGA interconnect for high frequency operation up to 40 GHz.