X/Ka-Band Dual-Polarized Digital Beamforming Synthetic Aperture Radar

This paper presents a digital beamforming (DBF) synthetic aperture radar (SAR) for future spaceborne earth observation systems. The objective of the DBF-SAR system is to achieve a low cost, lightweight, low-power consumption, and dual-band (X/Ka) dual-polarized module for the next-generation spaceborne SAR system in Europe. The architectures and modules of the proposed DBF-SAR system are designed according to a realistic mission scenario, which is compatible with the future small/microsatellites platforms. This system fills an important gap in the conception of the future DBF-SAR, facilitating a high level of integration and complexity reduction. The proposed system is considered not only the first demonstrator of a receive-only spaceborne DBF system, but also the first X/Ka-band dual-polarized SAR system with shared aperture. This paper presents a description of the proposed instrument hardware and first experimental validations. The concept and design of the DBF multistatic SAR system are discussed and presented first, followed by the design of subsystems such as DBF networks, microwave integrated circuit, and antennas. Simulated and measured results of the subsystems are presented, demonstrating that the proposed SAR instrument architecture is well-suited for the future SAR applications

The advanced model definition and analysis of orthodontic parameters on 3D digital models

Introduction/Objective Digital 3D modeling is slowly becoming an everyday orthodontic practice, and after two decades of research and development it is a basic element of e-orthodontics. The aim of this study was development and use of geometric entities on 3D digital models for diagnosing, planning and monitoring of orthodontic therapy, by using CAD (computer aided design) systems. Methods Statistical analysis and synthesis of 54 orthodontic parameters (28 in the upper and 26 in the lower jaw), defining three hypotheses and their testing, the application of the t-test. Results All three hypotheses are confirmed, convenience of using geometric entities, higher accuracy of 3D digital models, and more substantial displacement of teeth in the first six months of therapy (Student's t-test). After the first six months, distances in the x-y plane (occlusal plane) were bigger in both the upper and the lower jaw; additionally, the distances in the y-z plane (medial plane) decreased on the left and right side, so we can say that the first phase of therapy had success and that both jaws are wider. At the next four controls, parameters showed slight progress that was not statistically significant. Overall, after 11 months of therapy, there was a considerable improvement in the x-y plane, while changes in distances of clinical crown heights were very small. This could be explained by the fact that, during therapy, by using different arches, upper molars were pushed inside, toward the palate. Analyzing 3D computer models, we could notice that in this plane displacement of the upper left first molar was larger. Conclusion The use of geometric entities for defining orthodontic parameters gives us new possibilities for accurate and reliable analysis of patient's orthodontic condition.Uvod/Cilj 3D modeliranje postaje sve više svakodnevna ortodontska praksa, koja posle dve decenije istraživanja i razvoja biva bazni element e-ortodoncije. Cilj rada je bio da se izvrši razvoj i pokaže primena geometrijskih entiteta (GE) na 3D modelima za dijagnozu, planiranje i praćenje ortodontske terapije primenom opštih kompjuterski dizajniranih sistema. Metode Statistička analiza i sinteza 54 ortodontska parametra (28 za gornju vilicu i 26 za donju vilicu), definisanje tri hipoteze i njihovo testiranje, primena t-testa. Rezultati Potvrđene su sve tri hipoteze: pogodnost za primenu GE, veća tačnost 3D modela i veće pomeranje zuba u prvih šest meseci terapije (t-test). Posle prvih šest meseci uočeno je da su vrednosti rastojanja u x-y ravni (okluzalna ravan) u gornjoj i donjoj vilici veće, a da je pored toga došlo do smanjenja rastojanja u y-z ravni (medijalna ravan) i sa leve i sa desne strane, što znači da je prva faza terapije uspešno okončana i da je došlo do proširenja obe vilice u širini. U naredne četiri kontrole parametri su uglavnom pokazivali blagi rast, koji nije bio statistički toliko značajan. Sveukupno kad se sagleda, nakon jedanaest meseci terapije vidljiv je napredak u x-y ravni, dok su najmanja pomeranja viđena kod kliničkih visina krunica zuba. Ovo se objašnjava činjenicom da su tokom terapije, primenom određenih lukova, gornji molari uvučeni unutra, tj. pomereni prema nepcu. Analizom 3D digitalnih modela moguće je uočiti da je nastalo veće pomeranje kod gornjeg levog molara u ovoj ravni. Zaključak Primena GE za definisanje ortodontskih parametara daje nove mogućnosti za tačnu i pouzdanu analizu ortodontskog stanja pacijenta

60-GHz-Multimode-Chip-Satz und Demonstrator (EASY-A/IHP) : Schlussbericht

[no abstract available

A fully integrated fully differential low-noise amplifier for short range automotive radar using a SiGe:C BiCMOS technology

A fully integrated fully differential low-noise amplifier for 79 GHz short range radar applications using a high-speed SiGe:C BiCMOS technology is presented. The integrated circuit uses thin-film microstrip lines and exhibits compact design (530 x 690 um2), low power consumption (90 mW at 3 V supply voltage), high gain (13 dB gain at 81 GHz), good linearity and reverse isolation. In order to ease the measurements of the circuit, a simple technique was used to measure single-ended the differential amplifier. To overcome possible inaccuracy of the line model, shorting bars are placed along these elements to allow easy correction and to avoid redesign

Digital Beamforming Space-Borne Synthetic Aperture Radars

This workshop will present the most recent results of the European consortium project (funded by EU FP7) titled as DIFFERENT ((DIgital beam Forming For low-cost multi-static spacE-boRnE syNthetic aperTure radars). This is an ambitious multi-disciplinary project aiming to develop the next-generation high-performance low-cost digital beamforming space-borne multi-static synthetic aperture radars for small-satellite constellations in the Europe. Speakers will consist of leading researchers from each partners in the project, including German Aerospace Centre (DLR), Germany, Silicon Radars, Germany, University of Kent, UK, University of Calabria, Italy, IHP, Germany, EVATRONIX SA, Poland, and ISIS - Innovative Solutions In Space BV, Netherlands. The topics will cover millimeter-wave antennas and arrays, digital beamforming techniques, synthetic aperture radars, signal processing, FPGA, MMIC circuits designs, SiGe technologies and processes, small satellite platforms, etc

SiGe millimeter-wave dynamic frequency divider with enhanced sensitivity incorporating a transimpedance stage

A Si/SiGe bipolar dynamic frequency divider designed for 77 GHz/79 GHz automotive radar is presented, which uses a transimpedance amplifier topology to improve sensitivity and operational bandwidth. Capable of operation for input frequencies from 25 GHz up to 93 GHz, the divider consumes only 35 mA at 5 V supply voltage and has a very compact die area of 295 x 475 um2. In addition, measurements show that the divider operates in the full radar frequency band (76 GHz - 81 GHz) up to a temperature of 100 °C

Highly Integrated Dual-Band Dual-Polarized Antenna Tile for SAR Applications

The experimental assessment of a highly integrated dual-band (9.6 and 35.75 GHz) dual-polarized antenna tile designed for Synthetic Aperture Radar (SAR) Digital Beam Forming (DBF) satellite applications is presented. Antennas, transitions and down-conversion chips are integrated in the same board fabricated using a customized 15 layer PCB. The experimental assessment proves the validity of the proposed manufacturing and integration approaches, a good agreement between the performance of the individual blocks and of the integrated system has been demonstrated