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A sinusoidally corrugated periodic Bull's-Eye leaky wave antenna operating at 77 GHz is numerically and experimentally analyzed. Gain enhancement and bandwidth narrowing are observed as the number of periods is increased. Numerical and experimental results are in good agreement for the fabricated 20 period sinusoidal structure, showing a 28.9 dB gain with less than −20 dB side lobe level and a very...
In this work, a pulse shaper in coplanar technology intended for the unlicensed band up to the THz region is designed, fabricated, and measured. This broadband frequency range is of great interests as it offers very high data rate communication in local area networks. The technique employs tailored coplanar lines that have been designed using an exact analytical series solution of the synthesis problem...
In this communication, we study the effect of the position of SRR on the resonance frequency of the planar circuit. The idea is to better control the position of SRR along the Planar Goubau Line (PGL) in order to attain maximum rejection. This result is important for the design of terahertz circuits. As a demonstration of the flexibility and scalability of the designs, we show experimental results,...
For terahertz microscopy, we propose an original approach with Planar Goubau Lines (PGL) by taking advantage of the confinement around the metallic strip. The idea is to obtain an alternative to the illumination by free space wave. The structure is fabricated on a thin high resistivity silicon substrate and it is composed of two CPW-PGL transitions, two bendings and a coupling region between the two...
Leaky wave antennas have been studied since 1940s (C.H. Walter, Traveling Wave Antennas, Peninsula Pub., 1990). They have become a promising type of antenna for applications requiring low-profile antennas such as automotive radars (M. Ettorre, R. Sauleau, L. Le Coq, and F. Bodereau, IEEE Antennas Wirel. Propag. Lett. 9, 859, 2010). Unfortunately, pure broadside radiation cannot be achieved due to...
Low loss broad band transmission lines are of great interest for terahertz applications. To overcome high losses, Planar Goubau Lines (PGL) have been designed and fabricated on high resistivity silicon substrate. The measured loss level is typically 1dB/mm around 250GHz. The transitions are also extremely efficient for CPW-to-PGL conversion. The loss level depends on certain parameters such as length...
The electromagnetic field around Planar Goubau transmission Line (PGL) offers the possibility of tailoring the response of metamaterials components such as single or multi-micro resonators type. In this paper, we suggest a novel design of filter based on PGL coupled with micro split rings resonators (SRR). The frequency selectivity of resonant-type metamaterial transmission lines suggests their application...
By combining a UTC-PD as a THz emitter and a 400 GHz Schottky-based heterodyne detection, we realized an indoor THz link working up to 22 Gbps at 400 GHz carrier frequency with ultra-low THz power. The eye diagram at receiver is clearly opened are the system is working with only 1 µW received THz power.
Plasmonic metamaterials based on assemblies of metallic nanoparticles (MNPs) have finely tunable optical properties, which can be tailored for different applications, from sensing to waveguiding [1], [2]. Nanorods and nanorod arrays have been widely studied both theoretically and experimentally. In addition to the transverse and longitudinal localised surface plasmon resonances (LSPR), when arranged...
A dual-frequency laser coupled to a unitravelling carrier photodiode is used to produce a highly coherent THz wave. THz signal is detected by a subharmonic mixer coupled to an electrical spectrum analyzer. All components involved in this experiment operate at room temperature and no active stabilization is used. The measured linewidth is better than 30 kHz and tunable from DC to 1 THz. The dynamic...
It is shown that a continuous wave output power of 0.35 mW at 305 GHz can be generated by photomixing in a low temperature grown GaAs photoconductor using a metallic mirror Fabry-Pérot cavity. The output power is improved by a factor of about 100 as compared to the previous works on GaAs photomixers.
It is shown from on-wafer measurement that a continuous wave output power of 0.35 mW at 305 GHz can be generated by photomixing in a metal-metal Fabry-Pérot GaAs photoconductor.
The main properties of planar Goubau waveguides in the THz range are reported. Attenuation, dispersion and electric field confinement are measured using a guided-wave spectroscopy system based on a freely positionable electro-optic detector, and simulated using 3D electromagnetic field solver.
A novel transition has been conceived from microstrip (MS) to rectangular metallic waveguide (WG) with good matching over a broad band. Electromagnetic (EM) simulations confirm these properties and the actual fabrication has been shown feasible. S-Parameters measurements are underway.
Using a dual frequency Brillouin fiber laser and a 1.55 μm photomixer, we report the generation of a highly coherent kilo-Hertz level sub-millimeter wave emission. This system does not require any electrical synthesizer, and low cost telecom components are used to achieve very simple source architecture. The THz photomixer is composed of a uni-travelling carrier photodiode integrated with an antenna...
In this presentation advances on metallic lenses based on extreme electromagnetic parameters will be shown: either epsilon near zero or epsilon and mu near zero simultaneously. The former is generated by an array of continuous waveguides at cutoff, whereas the latter is composed of stacked subwavelength hole arrays that can be understood as discontinuous waveguides operating below cutoff.
Several flat antennas consisting of a central slot surrounded by a metallic periodic structure are proposed to enhance the radiation of quantum cascade laser terahertz sources. A simulation study of the optimal profile for high gain and radiation efficiency is done. Prototypes are being fabricated.
Quantum Cascade Lasers (QCL) are probably the most promising sources for Terahertz wave generation. The key issue especially for double metal QCLs is the extraction and the beam shaping of the emitted power. Several solutions have been proposed as possible antennas QCL.
We report the continuous wave generation delivered by on ion-irradiated In0.53Ga0.47As photomixers coupled to transverse-electromagnetic-horn antenna using two lasers operating at ~1.55 μm wavelength. Output powers up to 0.1 μW at 700 GHz have been achieved. The output power in a regime of Ohmic transport or recombination-limited transport is analyzed.
An AlGaN/GaN based field effect transistor (FET) has been designed, fabricated, and used as a resistive mixer for heterodyne detection in the 140-220 GHz frequency range. A double VNA heterodyne measurement setup has been used in an on-wafer configuration to accurately quantify the incident radiation absorbed by the device. The appropriate selection of optimum biasing conditions for minimum conversion...
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