Brother Joseph N. Streiff, S.M. 1918-1985

News release announces Brother Joseph M. Streiff, S.M., died at age 67 after suffering from leukemia

Detect and Avoid (DAA) Technologie für mittelgroße UAV

Dieser Vortrag fasst wichtige Konzepte und Ergebnisse des Projekts MasterUAS zur Integration unbemannter Luftfahrzeuge in kontrollierten Lufträumen zusammen. Insbesondere wird auf Anforderungen zu Detect-and-Avoid (DAA) eingegangen

Optimization of Uniplanar Multilayer Structures using Nonlinear Tunable Dielectrics

For an optimization of the tunability of coplanar waveguides (CPW) different geometries have been studied on Barium-Strontium-Titanate (BST) thick films. The presented measurement results show a strong dependency of tunability vs. geometry which can not be calculated using standard conformal mapping (CM) approaches. To calculate a cross section of a CPW, a FDTD (finite difference time domain) algorithm expanded to field strength dependent relative permittivities has been implemented. A geometry efficiency factor ? is introduced to review the effective tunability for different geometries

Passive Ferroelectric Phase Modulators for RFID Backscatter Transponders

Miniaturized, cost-effective reflection type phasemodulators for 2.45 GHz based on tunable ferroelectric thick films of Ba0.6Sr0.4TiO3 (BST) have been realized. Low cost screen printing technology is used for the substrate fabrication. The circuit area is below 2.4mm². The return loss of the first modulator is between 2.2 dB and 3.8 dB with a reflection phase shift of 72° and between 2.0 dB and 3.4 dB with a reflection phase shift of 71° for the second modulator. A third modulator design offers a DC-grounded RF port and a separate RF-decoupled modulation port

Suppression of Harmonic Radiation of Tunable PIFA by Thick-film BST Varactor Loading

Low-cost ferroelectric varactors based on Barium-Strontium-Titanate (BST) thick-film technology have been implemented in a tunable Planar Inverted-F Antenna (PIFA). A prototype is realized and measured. The harmonic radiation is evaluated in detail. It is shown that considerable RF voltage detunes the varactor and stimulates harmonic radiation in the varactor-loaded PIFA. It is discussed how such radiation can be suppressed by choosing the varactor?s tuning behavior. The passive BST thick-film varactors are proven to have advantages in reducing the harmonic excitation. When compared to a reference design using a silicon diode, the prototype shows suppressions on the second harmonic radiation up to 35.7 dB at -10 dBm input power. Possible suppression by BST thin-film varactors which are featured of low tuning voltages is also discussed