International Journal of Terahertz Science and Technology
Vol.5, No.4, December 2012. PP.153-200 (7)--Special Issue for UCMMT2012
date2012-12-31 11:51:08 Click No.3428

Special Issue for the 5th UK/Europe-China Workshop on Millimeter Waves and Terahertz Technologies UCMMT2012

The editorial office would to extend appreciation to Prof. Xiaodong Chen and Prof. Wei Hong, the Co-Chairs of the 5th UK/Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT2012), for their great support to this special issue.


TST, Vol. 5, No. 4, PP. 153-162

Self-consistent analysis of the IV characteristics of resonant tunnelling diodes

Jue Wang* and Edward Wasige
School of Engineering, University of Glasgow,
76 Oakfield Avenue, Glasgow, G12 8LT, United Kingdom
* Email:
j.wang.2@research.gla.ac.uk

(Received September 19, 2012)

Abstract: A self-consistent model for double barrier Resonant Tunnelling Diodes (RTD) has been investigated. The model involves using the Airy function to obtain an accurate transmission coefficient for electrons tunnelling through the barrier and the consideration of potential shift due to free charge distribution. It will serve to optimize the RTD structure for terahertz applications. A good agreement has been achieved between computed and measured IV characteristics of RTDs.

Keywords: Resonant tunnelling diode, Self-consistent, Airy function, Quantum well

doi: 10.11906/TST.153-162.2012.12.14

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TST, Vol. 5, No. 4, PP. 163-168

Development of a 105-130 GHz subharmonic mixer utilizing planar schottky diodes

Zhe Chen *, Bo Zhang and Yong Fan 
School of Electronic Engineering, University of Electronic Science and Technology of China
Chengdu, Sichuan, 611731, China
* Email:
zhechen_uestc@126.com

(Received September 19, 2012)

Abstract: The paper presents the design, fabrication and measurement of a low-loss fixed tuned 105-130 GHz subharmonically pumped mixer, utilizing planar GaAs Schottky barrier diodes flip-chipped onto a suspended microstrip circuit. The substrate material is 0.127-mm-thick RT/duriod-5880 instead of expensive quartz. The measurement performance of the mixer exhibits a conversion loss below 10 dB over the range of 105-130 GHz, with a fixed local oscillator (LO) frequency of 59 GHz and its power of 5 mW.

Keywords: Terahertz, Schottky diodes, Sub-harmonic mixer

doi: 10.11906/TST.163-168.2012.12.15

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TST, Vol. 5, No. 4, PP. 169-174

Dual-band terahertz metamaterial absorbers using two types of conventional frequency selective surface elements

Weiping Qin 1*, Jianhua Wu 1, Mingxun Yu 2, and Shibing Pan 2
1
School of Electronic Science and Engineering
Nanjing University of Posts and Telecommunications, Nanjing 210003 P.R. China
2 Shandong Nonmetallic Material Institute, Jinan 250031 P.R. China
*1 Email:
qinwp@njupt.edu.cn

(Received September 19, 2012)

Abstract: A simple means to obtain the performance of dual-band terahertz metamaterial absorber was demonstrated with numerical approaches in this paper. The dual-band absorbance of a single-layer nearly perfect absorber has been realized by employing the two conventional FSS single frequency resonant elements with different geometry shapes in single periodic cell, which can provide two tunable resonant frequencies independently for terahertz application.

Keywords: Terahertz, Metamaterial absorber, Dual band, Frequency selective surface.

doi: 10.11906/TST.169-174.2012.12.16

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TST, Vol. 5, No. 4, PP. 175-181

Design of an integrated THz electromagnetic crystals (EMXT)  cavity filter

Kai Zhou *, Yong Liu and Chao Zheng
School of Information and Electronics, Beijing Institute of Technology
South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China
* Email:
zkbit1227@163.com

(Received September 19, 2012)

Abstract: An electromagnetic crystals (EMXT) cavity filter with photonic band gap (PBG) structure is analyzed and a narrowband filter operating at around 0.5 THz is designed. The filter is simulated using the finite element method and it can be fabricated by micro-electromechanical systems (MEMS) technology, due to its low cost, high performance and high processing precision. The simulation results show the filter has a good performance. The passband bandwidth is 7%, the rejection at one time bandwidth out of the passband is larger than 30 dB, and the insertion loss in the passband is less than 1 dB.

Keywords: Terahertz, Cavity filter, PBG Structure

doi: 10.11906/TST.175-181.2012.12.17

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TST, Vol. 5, No. 4, PP. 182-188

Application of the diffracted gaussian beam analysis method in terahertz

Nan Chen 1*, Yuan Yao 1, Junsheng Yu 1, Xiaodong Chen 2, Zejian Lu 1, and Cheng Yang 1
1
School of Electronic Engineering, BeijingUniversity of Posts and Telecommunications
279Box, 10 Xi Tu Cheng Road, Haidian District, 100876, Beijing, China
2 School of Electronic Engineering and Computer Science, Queen Mary University of London,
Mile End Road, London El 4NS
*1 Email:
nanchen88@sina.com

(Received September 19, 2012)

Abstract:The use of millimeter and sub-millimeter wave antenna systems for the studies of space is of great significance to astronomy. This paper presents the application of Diffracted Gaussian Beam Analysis method (DGBA) in Terahertz. And a three dimensional visual software based on DGBA is used for the simulation of a single-channel quasi-optical system at 325GHz. The simulation results and comparison analysis between Simatrix and GRASP, which proves the accuracy of DGBA and the simulation by Simatrix in Terahertz are also presented.

Keywords: Terahertz, DGBA, Quasi-optical system

doi: 10.11906/TST.182-188.2012.12.18

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TST, Vol. 5, No. 4, PP. 189-195

A new approach to determinate parasitic elements of GaN HEMT by COLD FET S-Parameter

Min Han 1*, Yongsheng Dai 1, 2, Jianjun Zhou 2, Chao Liu 3, Xu Li 1
1
School of Electronic and Optical EngineerNanjing University of Science and Technology
Xiaolingwei 200, Nanjing, China
2 Nanjing Electronic Devices Institute
3 College Of Physics Engineering, Qufu Normal University
*1 Email:
hanzhenru@163.com

(Received September 19, 2012)

Abstract: A simplified approach to the parasitic elements of 2-gate figures GaN HEMT is introduced by pinch-off COLD FET S-Parameter. When extracting the parasitic parameter at pinch-off state, intrinsic circuit can be ignored as no current flows through it. As a result, if only taking extrinsic part into account, equivalent circuits constructed at different frequencies can extract different parasitic elements. With parasitic parameters from this approach, the simulation result of equivalent circuits agrees very well with experiments.

Keywords: Parasitic elements, GaN HEMT, COLD FET S-Parameter.

doi: 10.11906/TST.189-195.2012.12.19

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TST, Vol. 5, No. 4, PP. 196-200

Design and simulation of a 0.42 THz complex-cavity gyrotron

Xiang Li * , Xiaodong Chen
School of Electronic Engineering and Computer Science,
Queen Mary University of London, London E1 4NS, UK
* Email:
hj520beyond@gmail.com

(Received September 19, 2012)

Abstract: In this paper, the design parameters of a 0.42 THz, complex-cavity gyrotron are given in detail and the beam-wave interaction results are presented. It could be seen that an output power of 62.48 kW, 28.4% efficiency could be obtained with a 40 KV, 5.5 A electron beam(The grammar needs to be improved) when the operating magnetic is 7.95 T and the beam velocity ratio is 1.6.

Keywords: Complex-cavity, Gyrotron, THz

doi: 10.11906/TST.196-200.2012.12.20

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