Experimental Confirmation of Design Techniques for Effective Bow-Tie Antenna Lengths at THz Frequencies

Abstract

We present on the relationship between the bow-tie antenna length and its THz spectral emission response. Three well-known approaches for predicting accurate antenna length for a given central frequency were utilized and their validity was experimentally tested. It is shown that the simple quasi-static approach compare to other approximations is valid for frequencies up to~1.5 THz. The bow-tie THz photoconcudtive (PC) emitter designed using this approximation exhibits THz radiation having the most accurate central frequency compared to the design frequency. Interestingly, the THz PC emitter utilized from this design technique also possesses the optimum radiation bandwidth.

Effects of Antenna Design Parameters on the Characteristics of a Terahertz Coplanar Stripline Dipole Antenna

“…Various antenna designs, such as bow-tie [12], logarithm spiral [13], strip line [14], strip line dipole [15,16], and fractal-based antennas [17,18], have received significant attention for better generation and detection of THz radiation [19]. One of the most popular designs is the one that involves the use of a stripline dipole antenna, in which a center dipole is connected to coplanar striplines and forms an H-shaped electrode structure.…”

Impact of varying the DC bias stripline connection angle on terahertz coplanar stripline dipole antenna characteristics

“…[1][2][3][4][5] Various antenna geometries that implement the photoconductive antenna have received much attention as proven by the numerous theoretical and experimental studies in the literature. [6][7][8] The most popular design is the coplanar stripline dipole in which a center dipole is connected to a coplanar stripline and forms an Hshaped electrode structure patterned on a high-mobility semiconductor substrate. This design is the well-known Grischkowsky antenna and has received the most attention in the past decades because of its simple structure and the most successful commercial applications.…”

The Role of Self-Similarity in Fractal Photoconductive THz Emitters

“…The THz antennas and their biasing voltage electrodes were photolithographically patterned on thin metallic layers (20 nm/100 nm) of Cr/Au, forming bow-tie antennas of a 60°flare angle and an end-to-end length of 95 μm. Such an antenna length and the GaAs substrate ensures that the THz emitters operate at a peak frequency of 0.5 THz [8]. Electric field bias is provided to the antenna arms by means of two 10 μm wide transmission lines attached to the fractal bow-tie antenna elements to ensure that the biasing electric field at the optically-excited antenna feed point is the same for all of the THz emitters.…”

“…Accordingly, various PC THz emitters have incorporated surface antennas, such as strip-line dipole [1], bow-tie dipole [2,3], radially symmetric antenna [4], Schottky PC antenna and the multi-contacts PC antenna [5]. Specifically, the relationship between the geometric design parameters of different antennas and their emitted THz radiation properties has been investigated [1,[6][7][8][9]. Smith et al studied the spectral response of THz dipole antennas of different lengths [1].…”

“…More recently, Miyamaru et al [6] and Ezdi et al [7] reported on the relationship between the geometric parameters of a dipole antenna design and the temporal characteristics of the transient THz radiation emission. Moreover, Maraghechi et al [8] investigated the relationship between the THz radiation emitted from a bow-tie antenna and its geometrical scale. For a THz dipole-type PC emitter, the THz radiation feed point is comprised of an optically-excited semiconductor region, and the antenna arms serve as a means of distributing a biasing electric field necessary for the acceleration of the photogenerated electrons and holes.…”