Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

An Automatic Real Time Impedance Matching System for Use in an RF Electrostatics Accelerator Ion Source

Document Type : Research Paper

Authors

H Azizi
M Jafarzadeh Khatibani
J Rahighi

Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 11365-3486, Tehran - Iran

Abstract
This paper presents the design and construction of an apparatus in an RF ion source for automatic impedance matching between variable impedance environment (plasma) and fixed impedance system (an RF power generator) in order to transfer a maximum power to the plasma. The apparatus includes a matching box, a directional coupler and a balanced antenna associated with a transmission line transformer (TLT). The constructed automatic matching system is very simple and at the same time is capable of functioning under different conditions of the gas pressure to ensure a good performance. The matching network is mainly designed in order to be used in the first electrostatic accelerator designed and constructed in NSTIR, where the RF ion source is placed in the HV terminal, where there is no access to a manual matching box during the operation. The measured output current of the ion source is about 700µA with 200W RF power input in the working frequency of 70MHz. The output current of the previous ion source current could not exceed 200µA under the same condition (10-2 Torr) without employing the present matching system. The system is capable of reaching an optimum VSWR point of about 1.2 in the pressure range of 10-1 to 10-4 Torr. This can be realized in a short matching convergence time (i.e., couple of seconds).
 

Highlights

  1. M. Spencer, S. Saddow. “An automatic RF tuner for RIE applications,” Department of Electrical and Computer Engineering, Mississippi State University, January 24 (2000).

     

  2. Carl A. Sorensen, Wandell blonigan, John white, United states patents, Patent No. 5815047, Sep. 29, “Fast transition RF impedance matching network for plasma reactor ignition,” (1998).

 

  1. David Armitag “Automatic impedance matching,” United States patent, Patent No. 4356458, Oct. 26 (1982).

 

  1. Daisuke Matsuno, “Impedance matching apparatus,” United States patent, Publication No.: US2006/0151591 A1, (Jul.13, 2006).

 

  1. Richard N. Arounly, “Solid state plasma chamber tuner,” United States patent, Patent No. 5473291, (Dec. 5, 1995).

 

  1. Antone Marretic, Andrew Ciszek, Joseph Stach, “Apparatus for matching available load impedance with an RF power generator impedance,” United States Patent, Patent No. 5654679, (Aug. 5, 1997).

 

  1. Pil Jae park, Cheon Soo Kim, Mum Yang Park, “Variable impedance matching circuit,” United States Patent, Publication No.: US2004/0104785 A1, (Jun. 3, 2006).

 

  1. Jun Zhao, Kennet Smyith, Wiliam Nikson Taylor, Gerald McNut, “Plasma chamber with fixed RF matching,” United States Patent, Patent No. 5643364, (Jul. 1, 1997).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Advanced Energy Indusrties, Inc. Application note on Impedance matching, http: //www. advanced-energy.com/upload/File/White _papers/ EnG-WHITE18-270-02.pdf (2006).

 

  1. Chris Bowick, “RF circuit design,” Newnes Publication (1982).

 

  1. A.J. Bayly, A.G. Ward: Can. J. Res. 26A, 69 (1948).

 

  1. C.D. Moak, H. Reese, Jr., W.M. Good: Nucleonics 9, 21 (1951).

 

  1. John D. Swank, “VSWR monitor and alarm,” United States Patent, Publication No.: US2002/ 0113, 601, A1, (Aug. 22, 2002).

 

  1. David M. Pozar, “Microwave Engineering,” John Wily and Sons, Inc. (2005).

 

  1. Dominique-f1frv, “All powers SWR bridge and power meter,” (2006).

 

  1. Chris Trask, “Transmission line transformers: theory, design and applications,” Sonoran radio research. (January 2006) http: //www. highfrequencyelectronics. com/ Archives/ Jan06/ HFE0106_Traskpart2.pdf.

 

Keywords

RF Ion Source
Impedance Matching
Accelerator
VSWR
Plasma
Power Amplifier

  1. M. Spencer, S. Saddow. “An automatic RF tuner for RIE applications,” Department of Electrical and Computer Engineering, Mississippi State University, January 24 (2000).

     

  2. Carl A. Sorensen, Wandell blonigan, John white, United states patents, Patent No. 5815047, Sep. 29, “Fast transition RF impedance matching network for plasma reactor ignition,” (1998).

 

  1. David Armitag “Automatic impedance matching,” United States patent, Patent No. 4356458, Oct. 26 (1982).

 

  1. Daisuke Matsuno, “Impedance matching apparatus,” United States patent, Publication No.: US2006/0151591 A1, (Jul.13, 2006).

 

  1. Richard N. Arounly, “Solid state plasma chamber tuner,” United States patent, Patent No. 5473291, (Dec. 5, 1995).

 

  1. Antone Marretic, Andrew Ciszek, Joseph Stach, “Apparatus for matching available load impedance with an RF power generator impedance,” United States Patent, Patent No. 5654679, (Aug. 5, 1997).

 

  1. Pil Jae park, Cheon Soo Kim, Mum Yang Park, “Variable impedance matching circuit,” United States Patent, Publication No.: US2004/0104785 A1, (Jun. 3, 2006).

 

  1. Jun Zhao, Kennet Smyith, Wiliam Nikson Taylor, Gerald McNut, “Plasma chamber with fixed RF matching,” United States Patent, Patent No. 5643364, (Jul. 1, 1997).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Advanced Energy Indusrties, Inc. Application note on Impedance matching, http: //www. advanced-energy.com/upload/File/White _papers/ EnG-WHITE18-270-02.pdf (2006).

 

  1. Chris Bowick, “RF circuit design,” Newnes Publication (1982).

 

  1. A.J. Bayly, A.G. Ward: Can. J. Res. 26A, 69 (1948).

 

  1. C.D. Moak, H. Reese, Jr., W.M. Good: Nucleonics 9, 21 (1951).

 

  1. John D. Swank, “VSWR monitor and alarm,” United States Patent, Publication No.: US2002/ 0113, 601, A1, (Aug. 22, 2002).

 

  1. David M. Pozar, “Microwave Engineering,” John Wily and Sons, Inc. (2005).

 

  1. Dominique-f1frv, “All powers SWR bridge and power meter,” (2006).

 

  1. Chris Trask, “Transmission line transformers: theory, design and applications,” Sonoran radio research. (January 2006) http: //www. highfrequencyelectronics. com/ Archives/ Jan06/ HFE0106_Traskpart2.pdf.

 

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