Power-Divider-Networks with Integrated Antennas on Multilayer LTCC
a German BMBF/DLR Project (FKZ 50 YB 0007)

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Power Divider Network
2 Wilkinson power divider networks (1-to-4) buried in LTCC and 4 microstrip (MS) through lines on top of the circuitry have been designed in one compact mulitlayer module for space applications at 20GHz. The figure below shows an exploded view of the ground (green) and signal (yellow) layers. Via connections have been eliminated to simplify the graphic. The input ports of the 2 divider networks are on the left hand side of the module in the same level. All 12 output ports (4 for each divider network and 4 for each microstrip through line) are in the rear of the picture, while the 4 MS-line input ports can bee seen in the foreground. Each network consists of 3 Wilkinson power dividers, which have been optimized with the in-house EM-simulation tool EMPIRE. The final divider module is illustrated in in the photohraph inside a DISPAL housing. (further results: see References or Examples/Dividers)

Power divider networks in DISPAL housing

Exploded view of buried dividers in LTCC

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LTCC-RF-Benchmark
The goal of this workpackage was to compare the RF properties of different LTCC material systems. Test patterns have been designed for a common layout. Microstrip (MS) and stripline (SL) ring resonators have been chosen to characterize the effective (MS) and relative (SL) permittivity, the quality factor and the line losses of the LTCC substrates. The conductor line width is equal for each LTCC system to ensure that the results are comparable. The substrates' heights vary depending on the dielectric constants and the available standard tape thickness'. The layout files have been offered to several LTCC suppliers and foundry services for manufacturing the parts. IMST has performed the characterization and evaluation. The MS patterns have been tested up to 40GHz and the SL parts up to 25GHz. The following companies have contributed to this RF-benchmarking initiative: (further results: see References)

Front view of test tile (DuPont 943)

Back view of test tile (DuPont 943)

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Patch Antenna for Circular Polarization
The goal of this workpackage was to investigate suitable antenna patches for linear and circular polarization on multilayer LTCC substrates. The setup for both circuits is illustrated in the grahics below. The linear polarized patch in microstrip configuration is fed by a buried stripline (in blue) and is connected with a filled via. Ground to ground via chains are shielding the feeding line. The circular polarization is achieved by feeding the rotated patch from 2 buried striplines. The signals on the striplines have a phase difference of 90-degree, coming from a branch-line coupler. The E-field of the feeding circuitry and the circular polarization of the far field is illustrated in the pictures below. The 3D field simulation and the animation has been made with IMST's Finite Difference Time Domain simulation tool EMPIRE^TM. (further results: see References)

Circular polarization of simulated E-field