Abstract-A 90°-Inclined Linearly Polarized Probe for Terahertz Mueller Imaging

Xuexuan Ruan,  Kung Bo Ng, Huan Yi, Shi-Wei Qu, Chi Hou Chan, 

https://ieeexplore.ieee.org/document/8740178

A novel terahertz (THz) probe, consisting of a 90°-inclined linearly polarized (LP) component incorporated with a pyramidal-shaped TE 10 mode rectangular open-ended waveguide (OEWG), is introduced in this paper. The pyramidal feed, located beneath the substrate, is made of brass plated with gold. The radiation component, placed on tip of the OEWG, is achieved by standard printed-circuit and plated-through-hole techniques. Measurement results demonstrate that the proposed probe possesses an impedance bandwidth (VSWR ≤ 2) of better than 18.5% from lower than 270 to higher than 325 GHz. In the impedance bandwidth, the measured gain is from 7.2 to 8.2 dBi and all radiation patterns are relatively symmetric with relatively small back radiation and cross-polarization levels. The proposed probe is a potential component for Mueller imaging at THz frequencies.

Abstract-Flat Terahertz Reflective Focusing Metasurface with Scanning Ability

Huan Yi, Shi-Wei Qu, Bao-Jie Chen, Xue Bai, Kung Bo Ng,  Chi Hou Chan

https://www.nature.com/articles/s41598-017-03752-3

The ability to manipulate the propagation properties of electromagnetic waves, e.g., divergence, focusing, holography or deflection, is very significant in terahertz applications. Metasurfaces with flat structures are attractive for achieving such manipulations in terahertz band, as they feature low profile, lightweight, and ease of design and installation. Several types of terahertz reflective or transmitting metasurfaces with focusing function have been implemented recently, but none of them can provide scanning ability with controllable focus. Here, a flat reflective metasurface featuring controllable focal shift is proposed and experimentally demonstrated. Furthermore, the principle of designing a focus scanning reflective metasurface is presented and the focusing characteristics are discussed, including focus scanning along a line parallel or orthogonal to the metasurface with a large bandwidth. These interesting properties indicate that this flat reflective metasurface could play a key role in many terahertz imaging and detection systems.

Abstract-Terahertz Reflecting and Transmitting Metasurfaces

Shi-Wei Qu,  Huan Yi,  Bao Jie Chen,  Kung Bo Ng, Chi Hou Chan,

http://ieeexplore.ieee.org/document/7918550/

Bridging the terahertz gap requires synergism between the microwave and photonic communities. Advances in each of these two communities are often complementary but sometimes overlooked. One example is the manipulation of waves, known as anomalous diffraction via the use of metamaterials. This is achieved by controlling the surface impedance of each pixel at the interface of two different materials or alternately the phase and magnitude of the wave diffracted off the pixel. In this paper, a review of developments in wave manipulation from microwave to optical frequencies is presented, together with our new results in the terahertz regime. Generation of phase curves for pixel design requires a priori information on material properties at terahertz frequencies. Fabrication of terahertz devices entails micromachining in the clean room while their experimental validation demands both amplitude and phase information. Through judicial selection of practices in microwave and photonic communities, we can further the exploration of wave phenomena at terahertz frequencies.

Abstract-Controlling Dispersion Characteristics of Terahertz Metasurface

• • 
    
• • 
    
  • 
    
  • 
    
  • 
    
  • 
    
  Shi-Wei Qu,
• Wei-Wei Wu,
• Bao-Jie Chen,
• Huan Yi,
• Xue Bai,
• Kung Bo Ng
• & Chi Hou Chan

• Affiliations
• Contributions
• Corresponding author

Scientific Reports

 

http://www.nature.com/srep/2015/150323/srep09367/full/srep09367.html

Terahertz (THz) metasurfaces have been explored recently due to their properties such as low material loss and ease of fabrication compared to three-dimensional (3D) metamaterials. Although the dispersion properties of the reflection/transmission-type THz metasurface were observed in some published literature, the method to control them at will has been scarcely reported to the best of our knowledge. In this context, flexible dispersion control of the THz metasurface will lead to great opportunities toward unprecedented THz devices. As an example, a THz metasurface with controllable dispersion characteristics has been successfully demonstrated in this article, and the incident waves at different frequencies from a source in front of the metasurface can be projected into different desired anomalous angular positions. Furthermore, this work provides a potential approach to other kinds of novel THz devices that need controllable metasurface dispersion properties.

Subject terms:

• Electrical and electronic engineering
• Metamaterials
• Surfaces, interfaces and thin films
• Terahertz optics

At a glance

Figures

First | 1-2 of 6 | Last

View all figures

left

1. 

   Figure 1

2.