References of "Moonshiram, Anusha 50002691"
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See detailNano-light-emitting-diodes based on InGaN mesoscopic structures for energy saving optoelectronics
Mikulics, Martin; Winden, Andreas; Marso, Michel UL et al

in Applied Physics Letters (2016), 109

Vertically integrated III-nitride based nano-LEDs (light emitting diodes) were designed and fabricated for operation in the telecommunication wavelength range in the (p-GaN/InGaN/n-GaN/sapphire) material ... [more ▼]

Vertically integrated III-nitride based nano-LEDs (light emitting diodes) were designed and fabricated for operation in the telecommunication wavelength range in the (p-GaN/InGaN/n-GaN/sapphire) material system. The band edge luminescence energy of the nano-LEDs could be engineered by tuning the composition and size of the InGaN mesoscopic structures. Narrow band edge photoluminescence and electroluminescence were observed. Our mesoscopic InGaN structures (depending on diameter) feature a very low power consumption in the range between 2 nWand 30 nW. The suitability of the technological process for the long-term operation of LEDs is demonstrated by reliability measurements. The optical and electrical characterization presented show strong potential for future low energy consumption optoelectronics. [less ▲]

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See detailPhased Array Antenna with Dielectric Phase Shifters
Moonshiram, Anusha UL

Doctoral thesis (2016)

This PhD Thesis entitled, “Phased Array antenna with Dielectric Phase Shifters” presents a candidate for a planar, elegant and simple alternative to replace the parabolic antenna on the roof of your house ... [more ▼]

This PhD Thesis entitled, “Phased Array antenna with Dielectric Phase Shifters” presents a candidate for a planar, elegant and simple alternative to replace the parabolic antenna on the roof of your house and that of your neighbours. A parabolic antenna is bulky, has an average weight of 25 kg, and it is usually attached with an arm fixture of an average depth of 30 cm. Unlike the parabolic antenna which represents a large unsightly looking necessity on your roof, or balcony of your house, the planar antenna presented here is elegant and discrete. It is cheaply made with simple lightweight dielectric sheets and is mounted directly as a planar surface on the wall of your house oriented towards the satellite Astra 1M and requires no extra mount fixture. The planar antenna is less subjected to environmental conditions such as wind or hail and must not be constantly readjusted to optimize TV reception. The proposed antenna is made of 32 by 32 elements of a length and a spacing of half wavelength λ/2 with dielectric phase shifters to orient the main lobe with a 3° beamwidth by 45° in azimuth and from 23° to 43° in elevation. The dielectric phase shifters use a high dielectric constant of εr 10.2 on top of an antenna array with a substrate of εr 2.2. The difference between the high and the low dielectric value on a coplanar waveguide (CPW) feedline requires a maximum length of 18.7 cm for the 32nd antenna element in order to move the main lobe by a maximum of 45°. The CPW feedline is ideal to minimize mutual coupling among antenna elements. The antenna gain is 32 dBi and the beamwidth is 3°. It occupies a total size of 72.25 cm x 40.96 cm x 6.22 cm. The antenna presented here is targeted for the reception of satellite television in Europe broadcasting from 10.7 to 12.7 GHz. As it consists of frequency independent antenna elements, it can be resized for any desired frequency range in any part of the world. In short, it is a cheap, light, adaptable and discrete design and especially convenient in regions where unsightly parabolic antennas are prohibited. [less ▲]

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See detailDirect electro-optical pumping for hybrid CdSe nanocrystal/III-nitride based nano-light-emitting diodes
Mikulics, Martin; Arango, Y.C.; Winden, Andreas et al

in Applied Physics Letters (2016), 108

We propose a device concept for a hybrid nanocrystal/III-nitride based nano-LED. Our approach is based on the direct electro-optical pumping of nanocrystals (secondary excitation) by electrically driven ... [more ▼]

We propose a device concept for a hybrid nanocrystal/III-nitride based nano-LED. Our approach is based on the direct electro-optical pumping of nanocrystals (secondary excitation) by electrically driven InGaN/GaN nano-LEDs as the primary excitation source. To this end, a universal hybrid optoelectronic platform was developed for a large range of optically active nano- and mesoscopic structures. The advantage of the approach is that the emission of the nanocrystals can be electrically induced without the need of contacting them. The proof of principal was demonstrated for the electro-optical pumping of CdSe nanocrystals. The nano-LEDs with a diameter of 100 nm exhibit a very low current of 8 nA at 5V bias which is several orders of magnitude smaller than for those conventionally used. The leakage currents in the device layout were typically in the range of 8 pA to 20 pA/cm2 at 5V bias. The photon-photon down conversion efficiency was determined to be 27%. Microphotoluminescence and microelectroluminescence characterization demonstrate the potential for future optoelectronics and highly secure “green” information technology applications. [less ▲]

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See detailHigh Gain Patch Antenna for Broadband Applications from 10.1 to 14.2 GHz
Moonshiram, Anusha UL; Marso, Michel UL

in NNGT International Journal on Networking and Communication (2015), 4

This paper reveals a patch antenna with a large bandwidth of 34% and a high gain of 8 dBi in the frequency range from 10.1 to 14.2 GHz. The patch antenna is a four layer design comprising of a superstrate ... [more ▼]

This paper reveals a patch antenna with a large bandwidth of 34% and a high gain of 8 dBi in the frequency range from 10.1 to 14.2 GHz. The patch antenna is a four layer design comprising of a superstrate dielectric layer of εr 10.2 on top of a metal layer with six small simply designed parasitic H-shaped elements, which are optimized using CST Microwave Studio. The six H-shaped parasitic elements are centrally located on the metal layer. On the same layer, the antenna is fed through a coupled feedline so as to reduce mutual coupling and the antenna is thus a perfect candidate to preserve its wideband feature in an antenna array. Right underneath the metal layer is the substrate dielectric layer of εr 2.2 with two strategically placed slots underneath the metal layer in order to decrease the back radiation of the H-shaped parasitic elements. The whole design is terminated with a final metal layer to act as a conductor backed antenna to push most radiation out. The final antenna occupies a volume of 25 mm x 25 mm x 2.56 mm. The design has a high gain of 8 dBi in both the φ = 0° plane and the φ = 90° plane with a large beamwidth of 77° in the φ = 0° plane and 83° in the φ = 90° plane in the farfield. [less ▲]

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See detailUltra-Broadband Bow-tie Antenna
Moonshiram, Anusha UL; Marso, Michel UL

in NNGT International Journal on Networking and Communication (2015), 4

An ultra-broadband bow-tie with a VSWR < 2 from 5 to 60 GHz is revealed. The bow-tie antenna shows frequency independence properties and resonates periodically at multiples of its resonance frequency of 7 ... [more ▼]

An ultra-broadband bow-tie with a VSWR < 2 from 5 to 60 GHz is revealed. The bow-tie antenna shows frequency independence properties and resonates periodically at multiples of its resonance frequency of 7.7 GHz with the return loss always less than -10 dB. The antenna is linearly polarized and has a maximum directivity of 6 dBi in both the elevation and azimuth planes in the farfield. The antenna is a symmetrical design with straight ends and a flare angle of 90°. It is a simple metal layer on top of a substrate layer which is fed on the metal layer right at the center with closely spaced coplanar striplines. The flare angle and the straight-end of the bow-tie antenna are varied and the 90° straight-end bow-tie antenna is compared with three other bow-tie antennas with flare angle of 60° and round-ends. All four bow-tie antennas have a low VSWR. The E-fields, H-fields and impedance plots of the ultra-broadband bow-tie antenna are shown. The impedance plot is in fact the impedance of frequency independent antennas of 189Ω or 60π across all frequencies. [less ▲]

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See detailA Novel Stacked Slotted Bow-Tie Antenna Element at 11.7 GHz
Moonshiram, Anusha UL; Marso, Michel UL

in NNGT International Journal on Networking and Communication (2015), 4

This paper reveals a novel stacked slotted bow-tie antenna element with a large bandwidth resonating at 11.7 GHz for satellite TV broadcasts. The simple, cost effective antenna is built on common ... [more ▼]

This paper reveals a novel stacked slotted bow-tie antenna element with a large bandwidth resonating at 11.7 GHz for satellite TV broadcasts. The simple, cost effective antenna is built on common dielectrics and is a layered version of the popular patch antenna. It is shaped in a bow-tie and converted into the slotted version in order to increase the antenna radiating surface. The dual polarized antenna element offers a large directivity of 7.2 dBi in the farfield direction. It is terminated with a coplanar waveguide feedline which is ideal to preserve its large bandwidth in an antenna array configuration. In order to appreciate its results and its design simplicity, a comparison of its S-parameters, radiation patterns, E-fields and H-fields are made with five other popular elements at the center frequency of 11.7 GHz. [less ▲]

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