Modulated scattering technique in the terahertz domain enabled by current actuated vanadium dioxide switches

Abstract

The modulated scattering technique is based on the use of reconfigurable electromagnetic scatterers, structures able to scatter and modulate an impinging electromagnetic field in function of a control signal. The modulated scattering technique is used in a wide range of frequencies up to millimeter waves for various applications, such as field mapping of circuits or antennas, radio-frequency identification devices and imaging applications. However, its implementation in the terahertz domain remains challenging. Here, we describe the design and experimental demonstration of the modulated scattering technique at terahertz frequencies. We characterize a modulated scatterer consisting in a bowtie antenna loaded with a vanadium dioxide switch, actuated using a continuous current. The modulated scatterer behavior is demonstrated using a time domain terahertz spectroscopy setup and shows significant signal strength well above 0.5 THz, which makes this device a promising candidate for the development of fast and energy-efficient THz communication devices and imaging systems. Moreover, our experiments allowed us to verify the operation of a single micro-meter sized VO2 switch at terahertz frequencies, thanks to the coupling provided by the antenna.

3D Smith charts scattering parameters frequency-dependent orientation analysis and complex-scalar multi-parameter characterization applied to Peano reconfigurable vanadium dioxide inductors

“…Because of its ease of integration, reversible insulator to metal transition (IMT), low transition temperature and fast switching time, the employment of VO 2 as a reconfigurable radio frequency (RF) material has been just recently investigated for a variety of RF-reconfigurable devices 37,38,40,44,45 . Still, much of existing studies are carried out in the frequency range of terahertz or far-infrared 41,43,46,48 , leaving (RF) VO 2 a largely uncharted area for exploration in development. The conductivity levels of VO 2 in its insulating (off) state and in its conductive (on) state vary over a wide range depending on the substrate 37,38,40–49 causing limitations in the RF devices performances (being below 50,000 S/m for SiO 2 /Si depositions in the on state).…”

Dynamic Terahertz Plasmonics Enabled by Phase‐Change Materials

“…[63,[74][75][76][77][78][79][80] For example, a 1 mm by 1 mm sized array of gold slot nanoantennas resonating at ≈0.5 THz can be switched by a 500 V DC bias, with a 98% transmission tuning range (Figure 3a,b). Although electrical bias application is not considered a pure electrical process, it can still show a sufficiently fast switching speed (≈ns).…”

“…[77] The application of a continuous DC current to a few µm-sized gap of a bowtie antenna can control the scattering properties of the underneath VO 2 layer (Figure 3e,f). [77] The application of a continuous DC current to a few µm-sized gap of a bowtie antenna can control the scattering properties of the underneath VO 2 layer (Figure 3e,f).…”

“…While bare VO 2 film does not show any appreciable difference in the thermal IMT even under the intense THz field of 680 kV cm -1 , a THz field strength of less than 100 kV cm -1 is sufficient to observe a shift of the thermal hysteresis curve of THz transmission on nanoantenna-patterned VO 2 film. [77] Copyright 2017, The Author(s). One recent Adv.…”

Shunt capacitive switches based on VO2 metal insulator transition for RF phase shifter applications

“…Strongly correlated functional oxides exhibiting metal to insulator transition have recently emerged in research as promising materials for a large number of applications, including steep transistors [1], RF switches [2,3], reconfigurable filters [4,5] and antennas [6,7]. Vanadium Oxide (VO 2 ) has proven to be one of the most interesting among these materials thanks to its large change in conductivity between its two states and the possibility of achieving the phase transition by electrical excitation [8].…”