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Title: Efficient power combiner for THz radiation

Abstract

Most dangerous explosive materials, both toxic and radioactive, contain nitrogen salts with resonant absorption lines in the frequency range 0.3-10 THz. Therefore, there has been growing interest in remotely detecting such materials by observing the spectrum of reflected signals when the suspicious material is interrogated by THz radiation. Practical portable THz sources available today generate only 20–40 mW output power. This power level is too low to interrogate suspicious material from a safe distance, especially if the material is concealed. Hence, there is a need for sources that can provide greater power in the THz spectrum. Generating and extracting high output power from THz sources is complicated and inefficient. The efficiency of vacuum electronic microwave sources is very low when scaled to the THz range and THz sources based on scaling down semiconductor laser sources have low efficiency as well, resulting in the well known “THz gap.” The reason for such low efficiencies for both source types is material losses in the THz band. In this article an efficient power combiner is described that is based on scaling to higher frequencies a microwave combiner that increases the output power in the THz range of interest in simulation studies. The proposedmore » power combiner not only combines the THz power output from several sources, but can also form a Gaussian wavebeam output. A minimum conversion efficiency of 89% with cophased inputs in a lossy copper power combiner and maximum efficiency of 100% in a Perfect Electric Conductor (PEC)-made power combiner were achieved in simulations. Also, it is shown that the TE{sub 01} output mode is a reasonable option for THz applications due to the fact that conductive loss decreases for this mode as frequency increases.« less

Authors:
; ; ;  [1]
  1. Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, 87131-0001 (United States)
Publication Date:
OSTI Identifier:
22611376
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; CONVERSION; COPPER; EFFICIENCY; ELECTRIC CONDUCTORS; EXPLOSIVES; LOSSES; MICROWAVE RADIATION; NITROGEN; SEMICONDUCTOR LASERS; SEMICONDUCTOR MATERIALS; SIMULATION; SPECTRA; THZ RANGE; TOXICITY

Citation Formats

Seidfaraji, Hamide, E-mail: hsfaraji@unm.edu, Fuks, Mikhail I., Christodoulou, Christos, and Schamiloglu, Edl. Efficient power combiner for THz radiation. United States: N. p., 2016. Web. doi:10.1063/1.4962150.
Seidfaraji, Hamide, E-mail: hsfaraji@unm.edu, Fuks, Mikhail I., Christodoulou, Christos, & Schamiloglu, Edl. Efficient power combiner for THz radiation. United States. doi:10.1063/1.4962150.
Seidfaraji, Hamide, E-mail: hsfaraji@unm.edu, Fuks, Mikhail I., Christodoulou, Christos, and Schamiloglu, Edl. Mon . "Efficient power combiner for THz radiation". United States. doi:10.1063/1.4962150.
@article{osti_22611376,
title = {Efficient power combiner for THz radiation},
author = {Seidfaraji, Hamide, E-mail: hsfaraji@unm.edu and Fuks, Mikhail I. and Christodoulou, Christos and Schamiloglu, Edl},
abstractNote = {Most dangerous explosive materials, both toxic and radioactive, contain nitrogen salts with resonant absorption lines in the frequency range 0.3-10 THz. Therefore, there has been growing interest in remotely detecting such materials by observing the spectrum of reflected signals when the suspicious material is interrogated by THz radiation. Practical portable THz sources available today generate only 20–40 mW output power. This power level is too low to interrogate suspicious material from a safe distance, especially if the material is concealed. Hence, there is a need for sources that can provide greater power in the THz spectrum. Generating and extracting high output power from THz sources is complicated and inefficient. The efficiency of vacuum electronic microwave sources is very low when scaled to the THz range and THz sources based on scaling down semiconductor laser sources have low efficiency as well, resulting in the well known “THz gap.” The reason for such low efficiencies for both source types is material losses in the THz band. In this article an efficient power combiner is described that is based on scaling to higher frequencies a microwave combiner that increases the output power in the THz range of interest in simulation studies. The proposed power combiner not only combines the THz power output from several sources, but can also form a Gaussian wavebeam output. A minimum conversion efficiency of 89% with cophased inputs in a lossy copper power combiner and maximum efficiency of 100% in a Perfect Electric Conductor (PEC)-made power combiner were achieved in simulations. Also, it is shown that the TE{sub 01} output mode is a reasonable option for THz applications due to the fact that conductive loss decreases for this mode as frequency increases.},
doi = {10.1063/1.4962150},
journal = {AIP Advances},
number = 8,
volume = 6,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}