Optimization of photomixers and antennas for continuous-wave terahertz emission

Gregory, I. S.; Baker, Colin; Tribe, W. R.; Bradley, I. V.; Evans, Michael J.; Linfield, E. H.; Davies, A. G.; Missous, M.

doi:10.1109/jqe.2005.844471

Cited by 190 publications

(112 citation statements)

References 42 publications

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“…The latter is particularly interesting since THz photomixers generally show a very high and real output impedance. 15,16 It is noticeable that placing the source in an asymmetric position (closer to one extremity than the other) provides an additional degree of freedom for Z in . However, this leads in general to lower Z in .…”

Section: Thz Antennas Based On Graphenementioning

confidence: 99%

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets

Tamagnone

Gómez‐Díaz

Mosig

et al. 2012

Journal of Applied Physics

244

120

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The analytical basis for the resonances and anti-resonances of loop antennas and meta-material ring resonators J. Appl. Phys. 112, 094911 (2012) A metamaterial antenna with frequency-scanning omnidirectional radiation patterns Appl. Phys. Lett. 101, 173501 (2012) A leaky-wave groove antenna at optical frequency J. Appl. Phys. 112, 074320 (2012) An alternative method for the measurement of the microwave temperature coefficient of resonant frequency (τf) J. Appl. Phys. 112, 074106 (2012) Additional information on J. Appl. Phys.

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Section: Thz Antennas Based On Graphenementioning

confidence: 99%

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets

Tamagnone

Gómez‐Díaz

Mosig

et al. 2012

Journal of Applied Physics

244

120

View full text Add to dashboard Cite

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“…6 where it can observed that there is a slight variations in the resonance resistance as well as frequency using a cavity size of 10 ≤ w ≤ 14 µm. It should be noted that the minimum slot's size is limited by the required size of the photomixer, w p , which is in the order of 5 µm [5]. However, using a smaller slot may result in creating a short circuit between the ground plane and the photomixer's electrodes as well as with the vertical feeding probes in addition to creating stronger capacitive coupling between the photomixer and the ground plane.…”

Section: Resultsmentioning

confidence: 99%

“…The difference between the frequencies of the laser beams should be in the THz range. As a result a photocurrent will be induced between the photomixer metal electrodes, which can be transferred into a radiated THz wave using a properly designed antenna [5]. However, the photomixer presents a considerably high output impedance that is typically in the order of 10 kΩ [5].…”

Section: Introductionmentioning

confidence: 99%

“…As a result a photocurrent will be induced between the photomixer metal electrodes, which can be transferred into a radiated THz wave using a properly designed antenna [5]. However, the photomixer presents a considerably high output impedance that is typically in the order of 10 kΩ [5]. In addition, the photomixer is usually grown on a type III-V semiconductor substrate with a considerable thickness and a dielectric constant of ε r ≈ 12.9.…”

Section: Introductionmentioning

confidence: 99%

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A Photomixer Driven Terahertz Dipole Antenna With High Input Resistance and Gain

Yin¹,

Kennedy²,

Sarma³

et al. 2015

PIER M

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Abstract-A terahertz (THz) antenna is proposed that offers high input resistance and gain in the presence of an electrically thick GaAs substrate. The antenna is centrally fed using two vertical probes connected to a photomixer on a thin low temperature grown gallium arsenide (LTG-GaAs) film which is supported by the GaAs substrate. An input impedance of ∼ 3.3 kΩ has been achieved using a dipole antenna that is printed on a thin dielectric slab, and isolated from the supporting substrate using a metal ground plane. A square aperture has been introduced to facilitate the illumination of the photomixer with two laser beams. Furthermore, a frequency selective surface (FSS) has been incorporated in the configuration, which results in a broadside gain of ∼ 19 dBi at a resonance frequency of 0.97 THz.

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“…The terahertz radiation is of critical importance in the spectroscopy evaluation of airport security screening, medical imaging, polar liquids, industrial systems and composites as well [1]. Also the terahertz time domain spectroscopy (TDz-TDS) is leading noncontact accurate detection of flaws and impact damages in composites, in which the TDz-TDS is based on photoconductive switches, which rely on the production of few-cycle terahertz pulses using a femtosecond laser to excite a photoconductive antenna [2][3][4][5]. This can generate sub-picosecond bursts of THz radiation, and subsequently detect them with high signal-to-noise.…”

Section: Introductionmentioning

confidence: 99%

Influence of terahertz waves on the fiber direction of CFRP composite laminates

Hsu

Chiou

et al. 2013

AIP Conference Proceedings

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The importance of Carbon-fiber reinforced plastics (CFRP) are widely utilized due to more high performance in engineering structures. It was well known that a nondestructive technique would be very beneficial. A new terahertz radiation has been recognized for their importance in technological applications. Recently, T-ray (terahertz ray) advances of technology and instrumentation has provided a probing field on the electromagnetic spectrum. The THz-TDS can be considered as a useful tool using general non-conducting materials; however it is quite limited to conducting materials. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configuration using the terahertz time domain spectroscopy. However, the T-ray is limited in order to penetrate a conducting material to some degree. Here, the T-ray would not go through easily the CFRP composite laminates since carbon fibers are electrically conducting while the epoxy matrix is not. So, investigation of terahertz time domain spectroscopy (THz TDS) was made and reflection and transmission configurations were studied for a 48-ply thermoplastic PPS (poly-phenylene sulfide)-based CFRP solid laminate. It is found that the electrical conductivity of CFRP composites depends on the direction of unidirectional fibers. Also, the T-ray could penetrate a CFRP composite laminate a few ply based on the Efiled (Electrical field) of carbon fibers. The terahertz scanning images were made at the angles ranged from 0°t o 180° with respect to the nominal fiber axis. So, the images were mapped out based on the electrical field (Efield) direction in the CFRP solid laminates. Also, using two-dimensional spatial Fourier transform, interface C-scan images were transformed into quantitatively angular distribution plots to show the fiber orientation information therein and to predict the orientation of the ply. (2012) A mathematical proof of the zeroth "law" of thermodynamics and the nonlinear Fourier "law" for heat flow J. Chem. Phys. 137, 194109 (2012) Additional information on AIP Conf. Proc. ABSTRACT. The importance of Carbon-fiber reinforced plastics (CFRP) are widely utilized due to more high performance in engineering structures. It was well known that a nondestructive technique would be very beneficial. A new terahertz radiation has been recognized for their importance in technological applications. Recently, T-ray (terahertz ray) advances of technology and instrumentation has provided a probing field on the electromagnetic spectrum. The THz-TDS can be considered as a useful tool using general non-conducting materials; however it is quite limited to conducting materials. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (Į) are derived in reflective and transmission configuration using the terahertz time domain spectroscopy. However, the T-ray is limited in order to penetrate a conducting material to some degree. Here, the...

show abstract

Optimization of photomixers and antennas for continuous-wave terahertz emission

Cited by 190 publications

References 42 publications

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets

A Photomixer Driven Terahertz Dipole Antenna With High Input Resistance and Gain

Influence of terahertz waves on the fiber direction of CFRP composite laminates

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