Browsing Articole ştiinţifice by Author "OPREA, I."

Sort by: Order: Results:

  • 183 GHz Mixer on InGaAs Schottky Diodes 
    OPREA, I.; WALBER, A.; COJOCARI, O.; GIBSON, H.; ZIMMERMANN, R.; HARTNAGEL, H. L. (Oxford, 2010)
    This work reports on experimental results of a 183 GHz sub-harmonically pumped mixer based on InGaAs antiparallel diode pair. The diode structure provides extremely low parasitic capacitance of about 2.5 fF. Roughly estimated ...
  • Effect of Si-doping of the GaN barrier on the internal quantum efficiency of InGaN/GaN light-emitting diodes 
    SIRKELI, Vadim; YILMAZOGLU, Oktay; AL-DAFFAIE, S.; OPREA, I.; ONG, Duu Sheng; KUPPERS, Franko; HARTNAGEL, Hans Ludwig (Institutul de Fizică Aplicată al AŞM, 2016)
    In the past decade the AlInGaN-based light-emitting diodes (LEDs) have attracted attentions of most researchers as promising candidates to replace conventional lamps in lighting applications including general illuminations, ...
  • European Schottky-Diode Based Receiver Technology 
    COJOCARI, O.; HOEFLE, M.; MORO-MELGAR, D.; OPREA, I.; RICKES, M. (IEEE, 2019)
    This contribution summarizes recent achievements of European MM- and SubMM-Wave receiver technology using Schottky diodes and THz-MICs fabricated by so-called Film-Diode (FD) process. The FD-process has particularly been ...
  • Experimental validation of thermal model of MM-Wave frequency multipliers 
    OPREA, I.; COJOCARI, O.; SOBORNYTSKYY, M.; HARTNAGEL, H. L. (IEEE, 2013)
    This paper presents a method for estimation of junction temperature of a Schottky diode used in a recently developed frequency doubler to 332 GHz. Our particular interest was the validation of the thermal model of the diode ...
  • Heterostructure equivalence of step-recovery diodes for ballistic and diffusive electron resonance - a new concept for THz signal generation 
    HARTNAGEL, H. L.; SCHMIDT, L.-P.; NICOLAE, B.; OPREA, I.; SCHONHERR, D.; ONG, D. S.; SCHUR, J.; RUF, M. (IEEE, 2008)
    A heterostructure equivalent to the well-known step recovery diode principle, arranged as a double structure gives a new nonlinear device for highly efficient harmonic THz signal generation. Like in the case of step recovery ...
  • High Power Discrete Schottky Diodes Based 275-305 GHz Transceiver for FMCW-Rada 
    MORO-MELGAR, D.; COJOCARI, O.; OPREA, I.; HOEFLE, H.; RICKES, M. (IEEE, 2018)
    A heterodyne 275-305 GHz transceiver intended for frequency modulated continuous wave radar applications is presented here. A commercial E-band active multiplication chain is used to provide the required power and frequency ...
  • High Power High Efficiency 270-320 GHz Source Based on Discrete Schottky Diodes 
    MORO-MELGAR, D.; COJOCARI, O.; OPREA, I. (IEEE, 2018)
    A 300 GHz source based on discrete Schottky diodes technology is reported in this work. The high frequency part developed by ACST consists of two high power and high efficiency doublers, one at 135-160 GHz and a second one ...
  • High-Power MM-Wave Frequency Multipliers 
    COJOCARI, O.; MORO-MELGAR, D.; OPREA, I. (IEEE, 2019)
    A novel approach has been developed on monolithic integration of Schottky diodes with CVD diamond substrate for improved thermal dissipation. This allowed development of mmwave frequency multipliers with unmatched ...
  • Highly responsive planar millimeter wave zero-bias Schottky detector with impedance matched folded dipole antenna 
    HOEFLE, M.; HAEHNSEN, K.; OPREA, I.; COJOCARI, O.; PENIRSCHKE, A.; JAKOBY, R. (IEEE, 2013)
    A compact highly responsive planar zero-bias Schottky detector is proposed for uni-planar and low-cost fabrication. Various zero-bias Schottky diodes are investigated, in particular the optimization of impedance matching ...
  • Internal quantum efficiency enhancement of InGaN/GaN LEDs with Mg-Si pin-doped GaN quantum barrier 
    KÜPPERS, F.; SIRKELI, V. P.; YILMAZOGLU, O.; AL-DAFFAIE, S.; OPREA, I.; ONG, D. S.; HARTNAGEL, H. L. (Institutul de Fizică Aplicată al AŞM, 2018)
    In this work we study numerically the effect of Mg-Si pindoping of GaN quantum barrier within InGaN/GaN multi quantum wells (MQWs) on the internal quantum efficiency (IQE) of LEDs in comparison with LED devices with undoped, ...
  • Millimeter-wave receiver based on a folded dipole antenna and Schottky diode for maximum power transfer 
    MONTERO-de-PAZ, J.; UGARTE-MUÑOZ, E.; GARCIA-MUÑOZ, L. E .; SEGOVIA-VARGAS, D.; SCHOENHERR, D.; OPREA, I.; AMRHEIN, A.; COJOCARI, O.; HARTNAGEL, H. L. (IEEE, 2012)
    In this article a millimeter-wave (mm-wave) receiver based on a folded dipole antenna, zero bias Schottky diode and silicon (Si) lens is presented. The antenna is designed in such a way that its input impedance is equal ...
  • Single-Chip 135-160 GHz Doubler with more than 150 mW Output Power based on Discrete Schottky Diodes 
    MORO-MELGAR, D.; COJOCARI, O.; OPREA, I.; RICKES, M.; HOEFLE, H. (IEEE, 2018)
    Single chip doubler based on novel diamond-based discrete Schottky diodes is presented here. CVD Diamond technology has been integrated by ACST GmbH in the discrete diode structure to implement in high power multipliers ...
  • THz Schottky diodes on epitaxial AlGaAs-membrane 
    COJOCARI, O.; OPREA, I.; SYDLO, C.; ZIMMERMANN, R.; WALBER, A.; HENNEBERGER, R.; HARTNAGEL, H.-L. (IEEE, 2005)
    Schottky structures based on quasi-vertical diode (QVD) design concept are essentially improved by optimization of the GaAs/AlGaAs wafer layout and fabrication process. Insertion of a 4 mum-thin epitaxial AlGaAs layer ...

Search DSpace


Browse

My Account