THz fractal antennas for electrical and optical semiconductor emitters and receptors

Abstract

THz waves have recently attracted considerable interest mainly because of their various applications. Efficient and compact CW sources are currently under development. Their optimization requires the most efficient coupling of THz radiation from the intrinsic inner semiconductor source to the outside world. In terms of compactness and planarity, this is best achieved using antennas that are fabricated using common processes in semiconductor technology. Although most antennas are narrow band devices, wide bands are expected from fractal 2D geometries like the Sierpinski gasket. Original results are presented on the design, fabrication and THz transmission of 2D metallic fractal deposited on highly resistive GaAs substrate as well as on thin SiNx membranes. Experimental transmission measurements are compared to theory.

Multispectral Cesaro-Type Fractal Plasmonic Nanoantennas

“…Multifrequency fractal antenna designs have a long history in electrodynamics that dates back to the pioneering works of Jaggard, Puente-Baliarda and Pous, and Cohen, who systematically investigated the diffraction and radiation properties of a number of fractal antenna structures and demonstrated multiband and frequency-independent operation in the radio frequency (RF) regime. At present, the “fractal paradigm” has led to the engineering of a large number of devices that operate in the RF, such as miniaturized multiband patch antennas and radio frequency identification (RFID) tags, multispectral components in the microwave and THz frequencies, − and plasmonic nanoantennas in the optical spectrum. − In the context of multispectral plasmonics, prior work has focused on nanoantenna geometries based on Sierpinski carpets, H-tree fractal shapes, , Minkowski fractals, and Peano–Hilbert space-filling curves . Additionally, fractal structures based on the Cayley-tree geometry have also been recently investigated, and multiresonant behavior extending from near-infrared (NIR) to mid-infrared (MIR) spectral regions has been demonstrated …”

Refractive index sensing characteristics of dual resonances in rectangular fractal nano-apertures

“…Enhanced transmission from nanoscale fractal apertures [17,31] and molecular vibration mode sensing system have been demonstrated for infrared wavelengths [32,33]. Due to their extraordinary characteristics, fractal micro-and nano-structures have been used in many applications such as optical semiconductor emitters and receptors [34], frequency-selective surfaces [35], split ring resonators (SRRs) [36], compact photovoltaic devices [37], plasmonic metamaterials [33,38,39] and terahertz devices [40][41][42] In this study, we investigate the refractive index sensing characteristics of dual resonances in rectangular fractal (RF) nanoapertures. The spectral response and near field distributions are obtained for both x-and y-polarized illumination sources by using finite difference time domain (FDTD) method.…”

Transmission enhancement of the ellipse gold split rings

“…Due to its strong transmission phenomenon is widely used in various fields [3][4][5], many periodic [6][7][8][9] and aperiodic [10][11][12] metal structure have been discovered. Metamaterials have every electromagnetic property with needed at any frequency band in principle, but the design of high quality special matter remains challenging [13][14][15].…”