Development of local oscillator integrated antenna array for microwave imaging diagnostics

Kuwahara, D.; Ito, Naoki; Nagayama, Y.; Takahashi, Hayato; Yoshikawa, M.; Kohagura, J.; Yoshinaga, T.; Yamaguchi, S.; Kogi, Y.; Mase, A.; Shinohara, Shunjiro

doi:10.1088/1748-0221/10/12/c12031

Cited by 11 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The finline transmitter enables installation of the front-end LNA in the HMID. Figure 9 shows an assembly drawing of a 2 channel LIA [44,45]. The LIA consists of 6 important elements: horn antennas, waveguides (WG) to microstrip line (MSL) transmission, mixer, LO module, LO power divider, and IF transmission line.…”

Section: System Developmentmentioning

confidence: 99%

Development and application of radar reflectometer using micro to infrared waves

Mase

Kogi

Kuwahara

et al. 2018

Advances in Physics: X

Self Cite

View full text Add to dashboard Cite

Section: System Developmentmentioning

confidence: 99%

Development and application of radar reflectometer using micro to infrared waves

Mase

Kogi

Kuwahara

et al. 2018

Advances in Physics: X

Self Cite

View full text Add to dashboard Cite

“…The frequency resolution is Δ f = 1 GHz, and the observed frequencies of each channel are integers from 50 to 57 GHz, with eight channels in total. The detailed technical information regarding the LIA was described previously [14].…”

Section: View Area On Lhdmentioning

confidence: 99%

“…A microwave-imaging reflectometer was employed with ECEI on LHD until 2016 [8][9][10][11][12][13][14]. At the beginning of the D-D plasma experiment of LHD, we refined the receiving antennas called as Horn-antenna Millimeter Imaging Device (HMID) [13], which was originally developed by the LHD group.…”

Section: Introductionmentioning

confidence: 99%

Installation of New Electron Cyclotron Emission Imaging in LHD

Takahashi

Kuwahara

Tokuzawa

et al. 2018

Plasma and Fusion Research

View full text Add to dashboard Cite

A new electron cyclotron emission imaging antenna was designed and installed outside the torus on LHD. To improve the signal quality, we developed a local oscillator integrated antenna array (LIA), in which each channel has an internal local oscillation supply from a frequency-multiplier-integrated circuit. The labyrinth structure of the optical system comprises five mirrors to protect the LIA from plasma neutron emission. The initial results were obtained from the 2017 LHD experimental campaign. The MHD fluctuations and their fluctuation profiles were observed.

show abstract

“…This was enabled by a breakthrough regarding millimeter-wave components. By replacing the method of local oscillator (LO) signal supply from the conventional Horn antenna Mixer Array (HMA) by the Local Oscillator Integrated Antenna Array (LIA), we could solve issues described in references [5,6]. In addition, we have made some improvements to enhance the quality of the measurement signal.…”

Section: Introductionmentioning

confidence: 99%

Development of the Q-band ECE imaging system in the large helical device

Goto¹,

Tokuzawa²,

Kuwahara³

et al. 2022

J. Inst.

Self Cite

View full text Add to dashboard Cite

In this study, we developed the Electron Cyclotron Emission Imaging (ECEI) system with the Q-band in the Large Helical Device (LHD). ECEI measurement makes it possible to obtain the spatiotemporal structure of magnetohydrodynamics (MHD) instabilities in the high-β plasma. Although there were several difficulties for realizing the multi-channelization, such as local oscillator (LO) optics and an expensive high-power LO source, we have solved these problems by developing a Local Integrated Antenna array (LIA) which has an internal LO supply, using a frequency doubler integrated circuit on each channel, instead of a conventional Horn-antenna Mixer Array (HMA) with common LOs. In addition, we have made some improvements to enhance the quality of the measurement signal. First, we developed and introduced notch filters that prevent the strong Electron Cyclotron Resonance Heating (ECRH) stray signal from being mixed into the measurement circuit. Second, the position of the doubler built in the printed circuit board was reconsidered to prevent the mixing of higher harmonic components into the mixer. Also, we have adopted the Logarithmic detector (LOG detector) to deal with the wide dynamic range of the plasma fluctuation. After these improvements, for the first time, we could successfully obtain the initial results of the two-dimensional temperature distribution and its fluctuation distribution in the LHD.

show abstract

Development of local oscillator integrated antenna array for microwave imaging diagnostics

Cited by 11 publications

References 12 publications

Development and application of radar reflectometer using micro to infrared waves

Development and application of radar reflectometer using micro to infrared waves

Installation of New Electron Cyclotron Emission Imaging in LHD

Development of the Q-band ECE imaging system in the large helical device

Contact Info

Product

Resources

About