Tailoring of the nonlinear optical rectification in vertically and laterally coupled InxGa1-xAs/GaAs quantum dots for Tera-hertz applications: Under In/Ga inter-diffusion, indium segregation, and strains effects

We numerically investigate the Nonlinear Optical Rectification (NOR) of two laterally coupled lens-shaped InxGa1-xAs/GaAs quantum dots and two layers of InxGa1-xAs/GaAs coupled QDs along the growth axis. In addition, we have examined the impact of applying an external electric field, hydrostatic pressure, and temperature on the NOR under indium segregation inside the wetting layer (WL) and In/Ga inter-diffusion in the QD region. The three-dimensional Schrödinger equation (3D) is solved numerically using the finite difference method (FDM) within the framework of the effective mass. We have used the compact density matrix formalism to compute the NOR coefficient. Our findings reveal that the indium segregation and inter-diffusion phenomena significantly affect the NOR coefficient and should be considered appropriately. It is also found that the lateral and vertical coupling thicknesses significantly impact the NOR coefficient, and the structure under investigation has a resonant behavior in the terahertz domain (0.1–10 THz). Moreover, obtained results reveal that the applied electric field orientation and intensity significantly affect the NOR magnitude. Therefore, the NOR intensity reaches the maximum value, χ(0)(2)=50.10-7m/V, for a negative applied electric field, F = −10 kV/cm. Additionally, it was shown that the increase in the hydrostatic pressure shifts the NOR spectrum to higher energies (blue-shift), whereas increasing temperature has the contrary effect. It is worth noting that the NOR magnitude and its attributed resonance energy can be adjusted for THz devices with a good choice of the external factors mentioned above

Grey Box Non-Linearities Modeling and Characterization of a BandPass BAW Filter

In this work, the non-linearities of a 3G/UMTS geared BandPass Bulk Acoustic Wave ladder filter composed of five resonators were modeled using non-linear modified Butterworth-Van Dyke model. The non-linear characteristics were measured and simulated, and they were compared and found to be fairly identical. The filter's central frequency is 2.12 GHz, the corresponding bandwidth is 61.55 MHz, and the quality factor is 34.55

Grey Box Non-Linearities Modeling and Characterization of a BandPass BAW Filter

In this work, the non-linearities of a 3G/UMTS geared BandPass Bulk Acoustic Wave ladder filter composed of five resonators were modeled using non-linear modified Butterworth-Van Dyke model. The non-linear characteristics were measured and simulated, and they were compared and found to be fairly identical. The filter's central frequency is 2.12 GHz, the corresponding bandwidth is 61.55 MHz, and the quality factor is 34.55

Design of Frequency-Reconfigurable Triband Dipole Antenna Using Capacitive Loading

International audienceIn this work, a novel frequency-reconfigurable printed dipole antenna is reported. By embedding a capacitor in the capacitively loaded loop (CLL), we can easily generate and control an additional resonant frequency F3 besides the main resonant frequency of the basic dipole antenna F1= 2.3GHz (LTE band) and the CLL element F2 = 1.51GHz (GPS band). The proposed antenna achieves a frequency reconfigurable band with tuning range from 1.7 to 2.03 GHz (AWS, DCS and UMTS bands) when varying the capacitance values from 2 to 8pF with good gain and efficiency. The presented antenna has a compact size of 40 × 70 mm2. The proposed design is validated by simulations, displaying good results of impedance mismatch, gain pattern and radiation efficiency. The reconfigurability, range tuning and compact size makes the presented antenna well suitable for the future 5G systems to achieve dynamic spectrum access and deal with the spectrum shortage problem. © 2020 IEEE

Microstrip Stop-band RF Filter at Microwave Frequencies Using CLLs Elements

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