References of "Juul, Lars 40021114"
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See detailNumerical simulation of high impedance T-match antennas for terahertz photomixers
Juul, Lars UL; Mikulics, Martin; Marso, Michel UL et al

in Proc. SPIE 9585, Terahertz Emitters, Receivers, and Applications VI, 95850K (August 31, 2015); (2015, August)

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See detailNumerical study of high impedance T-match antennas for terahertz photomixers
Juul, Lars UL; Mikulics, Martin; Pereira, Mauro F. et al

in Optical and Quantum Electronics (2015), 47

This paper outlines an efficient numerical method to design terahertz photomixers. The simulations are benchmarked using measured power levels from results published in the literature. Next, the method is ... [more ▼]

This paper outlines an efficient numerical method to design terahertz photomixers. The simulations are benchmarked using measured power levels from results published in the literature. Next, the method is applied to two new photomixer designs based on the high impedance T-match antenna with bias supply DC-blocking structures for either a uniplanar layout or amultilayer structure for improved device reliability. Manufacturability is favoured by avoiding the use of airbridges, substrate thinning or under-etching. The estimated output power of the improved design is 9.0μW, which is an improvement of three times over the reference photomixer. [less ▲]

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See detailReduction of skin effect losses in double-level-T-gate structure
Mikulics, Martin; Hardtdegen, Hilde; Arango, Y. C. et al

in Applied Physics Letters (2014), 105

We developed a T-gate technology based on selective wet etching yielding 200 nm wide T-gate structures used for fabrication of High Electron Mobility Transistors (HEMT). Major advantages of our process ... [more ▼]

We developed a T-gate technology based on selective wet etching yielding 200 nm wide T-gate structures used for fabrication of High Electron Mobility Transistors (HEMT). Major advantages of our process are the use of only standard photolithographic process and the ability to generate T-gate stacks. A HEMT fabricated on AlGaN/GaN/sapphire with gate length Lg=200 nm and double-stacked T-gates exhibits 60 GHz cutoff frequency showing ten-fold improvement compared to 6 GHz for the same device with 2 um gate length. HEMTs with a double-level-T-gate (DLTG) structure exhibit up to 35% improvement of fmax value compared to a single T-gate device. This indicates a significant reduction of skin effect losses in DLTG structure compared to its standard T-gate counterpart. These results agree with the theoretical predictions. [less ▲]

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See detailOptimisation of Terahertz Photomixer Layout
Juul, Lars UL

Doctoral thesis (2014)

This thesis examines ways to improve the output power of LT GaAs terahertz photomixer circuits, by focusing on the large impedance mismatch between photoconductor and antenna which gives rise to loss of a ... [more ▼]

This thesis examines ways to improve the output power of LT GaAs terahertz photomixer circuits, by focusing on the large impedance mismatch between photoconductor and antenna which gives rise to loss of a large fraction of power, which could potentially have been absorbed by the antenna. Impedance matching is a known problem in the microwave domain, and in this work such approaches were implemented in the terahertz domain and evaluated using a commercial numerical simulation tool with measured material properties. ?e aim was to provide cost effective design suggestions which are easily integrated into existing single layer technologies. Evaluation of high impedance antennas with integrated DC-blocking showed improvements ranging from 1.5 to 3 times the output power compared to the 3.0 µW reference case at 0.85 THz. A quarterwave transformer with an added shunt capacitance shows a 4 times improvement over the reference case. Adding a multilayer DC-block structure yields a 5 times improvement. Corrugated high impedance wire structures were evaluated for suitability in terms of radiative and transmission properties, in search for improved matching elements. Furthermore, a mechanically tunable resonant photomixer has been proposed, which yields significant improvement in output power over existing tunable broadband photomixers. Finally, a modulation scheme is proposed for binary ASK-modulation in the gigabit per second range of a terahertz photomixer, using an off the shelf 10 Gbps output driver. [less ▲]

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See detailImproving output power of terahertz heterodyne photomixer by impedance matching
Juul, Lars UL; Mikulics, Martin; Marso, Michel UL

in ASDAM 2012, The Ninth International Conference on Advanced Semiconductor Devices and Microsystems (2012)

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See detailGaAs nanowhiskers for femtosecond photodetectors and THz emitters
Mikulics, Martin; Zhang, J.; Sobolewski, Roman et al

in ASDAM 2012, The Ninth International Conference on Advanced Semiconductor Devices and Microsystems (2012)

Detailed reference viewed: 132 (0 UL)