Showing posts with label terahertz antennas. Show all posts
Showing posts with label terahertz antennas. Show all posts

Tuesday, April 21, 2020

NSF Funds Multidisciplinary U of A Team to Improve Imaging Technology


From left: Magda El-Shenawee, principal investigator and professor of electrical engineering; Hugh Churchill, assistant professor of physics; and Robert Coridan, assistant professor of chemistry.
https://news.uark.edu/articles/52782/nsf-funds-multidisciplinary-u-of-a-team-to-improve-imaging-technology

University of Arkansas researchers received funding from the National Science Foundation to advance imaging technology that could help improve breast cancer treatment, protect airline travelers and advance the nation's 5G network.
Three professors were awarded $456,070 from the NSF to support their research into high-frequency antennas, which are a critical part of imaging technology. The team is composed of Magda El-Shenawee, principal investigator and professor of electrical engineering, Hugh Churchill, assistant professor of physics, and Robert Coridan, assistant professor of chemistry.
Researchers are working to create more effective terahertz photoconductive antennas by using a new material — black phosphorus. The research includes three main components, modeling, fabrication, and measurements.
Terahertz radiation falls between infrared and microwave radiation on the electromagnetic spectrum. It is useful for a variety of applications because it can penetrate non-conductive materials like clothing, cardboard and wood, however, its penetration of body tissue is in micrometers.
El-Shenawee's research has been focused for years on terahertz technology to improve imaging for use in identifying breast cancer tumor margins to help doctors make better decisions when assigning treatments. She previously developed terahertz antennas based on plasmonic nano-disks using low temperature Gallium Arsenide (GaAs). The idea to use black phosphorous in this new project came from Churchill, a physicist whose research interests include 2-D semiconductors, like black phosphorous. The collaboration began through a project made possible by the Chancellor's Fund for Innovation and Collaboration.
That collaboration allowed the pair to examine whether black phosphorous would work as a component of terahertz antennas, and computer simulations suggested it could be 10 times more effective than current technology. They'll also work with dielectric nanoparticle coatings, which Coridan uses in his solar cell research, to increase the efficiency of the new antenna.  
"We want to maximize the fraction of the incident light that is absorbed in the black phosphorous layer," Coridan said. "Adding a layer of nanoparticles will scatter light in directions that will make the black phosphorous seem to be thicker than it is. This passive structure increases the light absorption in the black phosphorous layer, while reducing reflection or absorption of other parts of the device."
Black phosphorous could also increase the speed of communication between devices on the 5G network, which has a wide variety of applications. 
"If your car has 5G technology, it has an antenna to communicate with other vehicles to detect its location. This detection allows the vehicle to stop automatically when it needs to, so improving the signal speed between these devices can help vehicles sense objects faster, reducing the chances of an accident," El-Shenawee said.
El-Shenawee said the project is a unique collaboration.
"This is my first time working with three different disciplines on a promising idea like this one," El-Shenawee said. "The three of us think differently, but it is quite interesting."
Churchill said the team is excited and grateful for the support they have received.
"I would like to express our team's gratitude for the phenomenal institutional boost our team received to catalyze this interdisciplinary effort, which included Chancellor's Fund support to obtain preliminary data and Arkansas Biosciences Institute support to obtain crucial equipment to test our novel devices," he said.

OUTREACH TARGETING UNDERREPRESENTED STUDENTS

The NSF funding will also support outreach initiatives geared toward underrepresented K-12 students and their teachers in Arkansas.
"When we presented the concepts of antennas and wave traveling to students in K-12 summer camps, they were very excited," El-Shenawee said. 
The camps are coordinated by Amy Warren, assistant director of outreach and summer programs in the College of Engineering.
El-Shenawee said the team will work with Warren on creating unique opportunities and activities for underrepresented students in Arkansas.
"Even the youngest students are familiar with technologies that utilize antennas, but most do not gain any understanding of the concepts underlying this technology until high school," Warren said. "The outreach initiatives will give K-8 teachers and students the tools needed to teach these complex concepts earlier."
El-Shenawee, Churchill and Coridan said they hope this will encourage students to consider majoring in science and engineering-based fields.
The team hopes to have the project completed by 2023.

Monday, February 18, 2019

Abstract-Active Thermal Control of 5 nm Gap Terahertz Antennas



Hyeong Seok Yun  Jeeyoon Jeong,   Dasom Kim,   Dai‐Sik Kim,

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adom.201800856

Metallic nanostructures are combined with various active materials for electrical, optical, and thermal modulations of their optical properties. In particular, for the thermal modulation, deformation of metallic nanostructures at high temperatures limits the applications to relatively low temperatures, where thermal expansion of metals is negligible. Here, a unique regime is reported where terahertz (THz) waves transmitting through 5 nm wide slot antennas can be significantly modulated via controlled thermal expansion of metals without active materials. The normalized amplitude is modulated by 20% and the resonant frequency by 22% at an elevated temperature of 150 °C, indicating a decrease in the gap width by 50%. The extreme width‐to‐length ratio of the THz slot antennas compensates the small thermal expansion coefficient of metals, enabling the gap width to be considerably changed. COMSOL simulation and coupled‐mode method (CMM) calculation quantitatively support the experimental data. This works suggests a new possibility of thermally active metallic nanostructures.

Wednesday, November 21, 2018

Abstract-Design and analysis of a terahertz antenna for wireless body area networks


Qudsia Rubani, Sindhu Hak Gupta, Shuchismita Pani, Arun Kumar,

Fig. 1. Illustration of a WBAN

https://www.sciencedirect.com/science/article/pii/S0030402618317285

This paper has been formulated with an idea where we are considering the needs and demands of high data rates, due to the scarcity of spectrum available for wireless communication. Therefore the time has come when the higher frequency levels of the electromagnetic spectrum for wireless communications should be seriously looked forward to. For that the use of higher bands (terahertz frequency band) in future convincing systems and devices, has been considered and analysed in this paper. A microstrip patch antenna at THz frequency has been designed and analysed in this paper which is supposed to be implemented in Wireless Body Area Networks for the signal transmission. Further the amount of power transmission at varying distance between transmitter and receiver in WBAN has been analysed at different modulation schemes

Sunday, February 4, 2018

Abstract- Dual slot-superstrate terahertz antenna without Si-lens


Jiri Frydrych,  Jiri Petrzela, Kamil Pitra

http://ieeexplore.ieee.org/document/7932357/

Design study is presented concerning the structure of dual slot - superstrate antennas operating at 1 THz for signal sources LT-GaAs photomixer. The antenna directivity is strong enough to remove Si lens from the conventional THz emitter. The input impedance of the antenna was matched to the impedance of the photomixer to achieve high output power. The designed structure was verified by simulations in CST Microwave Studio.

Thursday, December 21, 2017

Abstract- Low-cost wideband low-THz antennas for wireless communications and sensing



Chao Gu,   Steven Gao,  Benito Sanz-Izquierdo

http://ieeexplore.ieee.org/document/8068470/

Terahertz technology is expected to provide a significant improvement in wireless system performance. A common assumption is that traditional microwave devices can be scaled down to operate at higher frequency bands. However, it can be a challenge to directly transfer the design methodology from microwave to THz band as the size of the devices becomes a few millimeter large. The reduced antenna size at the THz band limits the suitable fabrication processes. This paper reviews a wide range of THz antennas and their fabrication methodology. Then based on the resonant cavity antenna concept, an all-metal 300 GHz wideband high-gain antenna is designed and simulated. The presented metallic antenna is suitable to be fabricated using 3D printing techniques, which can lead to a low-cost, reliable solution for the emerging THz applications.

Sunday, November 5, 2017

Abstract-High impedance monopole antenna for indoor terahertz wireless communication systems


Ayhan Yazgan,  Jordi Romeu,  Lluis Jofre,

http://ieeexplore.ieee.org/document/8076103/

In this study, a wideband terahertz antenna for indoor wireless communication systems is proposed. Antenna has high input impedance which is reasonable for terahertz systems due to the high output impedance of terahertz sources. Proposed antenna has been designed to operate in 0.67 THz which is one of the appropriate frequencies considering the atmospheric attenuation conditions for short range indoor terahertz wireless communication systems. Designed antenna has 0.8 kohm input impedance at the center of the band and approximately 100 GHz −10 dB bandwidth at 0.67 THz.

Tuesday, October 17, 2017

Abstract-IR-Fresnel zone plate lens acting as THz antenna



Alicia E. Torres-Garcia.  Bakhtiyar Orazbayev,  Inigo Ederra, Ramon Gonzalo,


http://ieeexplore.ieee.org/document/7970309/

A Fresnel Zone Plate Lens designed for the Mid-IR is modified for acting as a THz Antenna. This proposal is the base for a dual band detector consisting of a Silicon (Si) substrate with a quasi-spiral antenna detector working at THz frequencies which acts also as a modified Fresnel Zone Plate Lens for an IR detector. The focal properties of the proposed lens have been studied numerically, and its behavior as a submillimeter wave receiver has been demonstrated by a 3D full-wave simulator.

Monday, February 27, 2017

Abstract-CMOS Integrated Lock-in Readout Circuit for FET Terahertz Detectors


    Suzana Domingues, Daniele Perenzoni, Matteo Perenzoni, David Stoppa, 
https://link.springer.com/article/10.1007/s10762-017-0372-3

In this paper, a switched-capacitor readout circuit topology integrated with a THz antenna and field-effect transistor detector is analyzed, designed, and fabricated in a 0.13-μm standard CMOS technology. The main objective is to perform amplification and filtering of the signal, as well as subtraction of background in case of modulated source, in order to avoid the need for an external lock-in amplifier, in a compact implementation. A maximum responsivity of 139.7 kV/W, and a corresponding minimum NEP of 2.2 nW/√Hz, was obtained with a two-stage readout circuit at 1 kHz modulation frequency. The presented switched-capacitor circuit is suitable for implementation in pixel arrays due to its compact size and power consumption (0.014 mm2 and 36 μW).

Monday, March 7, 2016

Abstract-Accurate equivalent circuit model for millimetre-wave UTC photodiodes



Michele Natrella, Chin-Pang Liu, Chris Graham, Frederic van Dijk, Huiyun Liu, Cyril C. Renaud, and Alwyn J. Seeds
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-5-4698

We present a comprehensive study of uni-travelling carrier photodiode impedance and frequency photo-response supported by measurements up to 110 GHz. The results of this investigation provide valuable new information for the optimisation of the coupling efficiency between UTC-PDs and THz antennas. We show that the measured impedance cannot be explained employing the standard junction-capacitance/series-resistance concept and propose a new model for the observed effects, which exhibits good agreement with the experimental data. The achieved knowledge of the photodiode impedance will allow the absolute level of power emitted by antenna integrated UTCs to be predicted and ultimately maximized.
© 2016 Optical Society of America
Full Article  |  PDF Article

Monday, December 21, 2015

Book-Terahertz Antenna Technology for Space Applications


By Balamati Choudhury, Aniruddha Sonde, Rakesh Mohan Jha

http://ebookde.com/terahertz-antenna-technology-space-applications.html

This book explores the terahertz antenna technology towards implementation of compact, consistent and cheap terahertz sources, as well as the high sensitivity terahertz detectors. The terahertz EM band provides a transition between the electronic and the photonic regions thus adopting important characteristics from these regimes. These characteristics, along with the progress in semiconductor technology, have enabled researchers to exploit hitherto unexplored domains including satellite communication, bio-medical imaging, and security systems. The advances in new materials and nanostructures such as graphene will be helpful in miniaturization of antenna technology while simultaneously maintaining the desired output levels. Terahertz antenna characterization of bandwidth, impedance, polarization, etc. has not yet been methodically structured and it continues to be a major research challenge. This book addresses these issues besides including the advances of terahertz technology in space applications worldwide, along with possibilities of using this technology in deep space networks.

Wednesday, December 3, 2014

University of Birmingham -Research Fellow on an EPSRC-funded project Terahertz Technology for Future Road Vehicles

University of Birmingham
http://brightrecruits.com/job/6889/research-fellow-on-an-epsrc-funded-project-terahertz-technology-for-future-road-vehicles

Research Fellow on an EPSRC-funded project Terahertz Technology for Future Road Vehicles

£28,695 to £39,685 per annum | Central England | 03 Dec 2014
Starting salary for this post is between £28,695 and £37,394 per annum with potential progression up to £39,685 a year once in post subject to satisfactory performance.

The post is a Fixed Term Contract - Post is available for up to 36 months.
Applications are invited for a three-year full-time research position in the School of Electronic, Electrical and Computer Engineering at the University of Birmingham, to undertake research in the area of mm-wave and Terahertz antennas and beamformers. The large-scale four year project is funded by EPSRC and addresses the different aspects of antenna technologies, fabrication procedures and systems integration aspects for use in vehicles and unmanned mobile platforms using sub-mm or low THz waves (300 GHz to 1 THz).
The overall aim of this cutting edge project is to lay the fundamental scientific foundations and develop new antenna technologies for automotive radar imaging systems. This will require undertaking theoretical and applied research, involving experimental studies, simulation and modelling. The research aims to determine suitable antenna and beamformer structures for a range of automotive applications of low THz imaging systems, based on cost effective fabrication processes, which will lead to prototype demonstrators and testing in representative systems.
The Research Fellow will work closely with other Research fellows focusing on micromachining fabrication processes and on radiowave propagation and remote sensing. In addition, the post requires close liaison with prestigious industrial partners for integration of the research results and prototypes with existing state of the art sensing technologies.
The project will take place in the Wireless Communications, Remote Sensing and Emerging Device Technologies research groups, where the underlying science, the new technologies and the applications of low THz EM waves are an increasingly important part of the research strategy, which is strongly backed by UK and EU funding. The involvement of major international companies further highlights the importance of the research and the potential impact that can be generated by cooperative work on fundamental research questions.
Person Specification:
The post is available for both UK/EU and international candidates (subject to work permit approval), who should have, or expect soon to obtain, a PhD degree in electronic engineering or physical sciences, ideally with previous experience of conducting research in antenna design, microwave engineering or computational electromagnetics. A mixture of theoretical, experimental and computational skills, as well as mm-wave related expertise will place an applicant in a particularly strong position.
How to apply: 
To download the details of this position and submit an electronic application online please visit hr.bham.ac.uk/jobs, quoting Job Ref in all enquiries. The applicant is required to upload a covering letter, a brief statement of research interests (describing how past experience and future plans fit with the advertised position), CV and the details of two referees as part of his or her online application.
Informal enquiries may be addressed to the project leader Dr. Peter Gardner (p.gardner@bham.ac.uk), or, specifically to the work package investigators Dr. Alex Feresidis (a.feresidis@bham.ac.uk).
Closing date:  5th January 2015