• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2289-2295
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• 2006

In this paper, We have proposed an Heterodyne technique to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase-array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of 300GHz.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.357-363
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• 1999

A frequency domain spectroscopic system was constructed to investigate the optical properties of multiple scattering media. The alternating current (AC) and phase lag components of backscattered light were measured by using the heterodyne detection method. Absorption and transport scattering coefficients were computed from the values based on diffusion theory. Predictions showed excellent matches in comparison with actual values of absorption and scattering. Predictable ranges of the optical coefficients were analyzed in terms of the distance between light source and detector, and modulation frequencies. A proposed compact experimental set-up using laser diodes can be utilized to estimate non-invasively the optical properties of multiple scattering media such as biological tissues.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.659-665
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• 2008

We demonstrate experimentally that the method of Two-pupil optical scanning technique with PAL-spatial light modulator is capable of performing real-time joint transform correlation(JTC) optical system. Optical addressing is achieved by the use of a photosensitive layer of $\alpha$ - Si which controls the electric field across the liquid crystal The demonstrated technique is based on two-pupil optical heterodyne scanning. The method is independent of a spatial light modulator (SLM) in the Fourier plane. We develop the theory of the technique and evaluate a performance of the method by experimentally estimating the correlation between the target image and the reference image.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.530-536
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• 2002

The accurate measurements of thermal expansion coefficients is one of the most important techniques required not only in material science but also in industries. A high precision interferometric dilatometer, using acoustic optical modulator, has been constructed and its performance has been tested. The system consists of a double-path optical heterodyne interferometer and a radiant heating furnace. This provides highly accurate length measurement, and allows rapid heating and cooling method for the specimen. A three longitudinal mode frequency stabilized He-Ne laser, using the secondary beat frequency, is constructed. Its stability is found to be $5{\times}10^{-9}$. The uncertainty in the length measurement is estimated to be of nanometer order in the range between room temperature to 1100 K.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2769-2774
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• 2010

In this paper, we have proposed sideband injection locking method, heterodyne technique, to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase-array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of tens of GHz applicable to LMDS. We experimented and analysed the generation of millimeter wave signal.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.210-219
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• 2005

We report on a low-cost V-band wireless transceiver with no use of any local oscillator in the receiver block using a self-heterodyne architecture. V-band millimeter-wave monolithic IC (MMIC) modules were developed to demonstrate the wireless transceiver using coplanar waveguide (CPW) and GaAs PHEMT technologies. The MMIC modules such as the MMIC low noise amplifier (LNA), medium power amplifier (MPA) and the up/down-mixer were installed in the transceiver system. To interface the MMIC chips with the component modules for the transceiver system, CPW-to-waveguide fin-line transition modules of WR-15 type were designed and fabricated. The fabricated LNA modules showed a $S_{21}$ gain of 8.4 dB and a noise figure of 5.6 dB at 58 GHz. The MPA modules exhibited a gain of 6.9 dB and a $P_{1dB}$ of 5.4 dBm at 58 GHz. The conversion losses of the up-mixer and the down-mixer module were 14.3 dB at a LO power of 15 dBm, and 19.7 dB at a LO power of 0 dBm, respectively. From the measurement of V-band wireless transceiver, a conversion gain of 0.2 dB and a $P_{1dB}$ of 5.2 dBm were obtained in the transmitter block. The receiver block showed a conversion gain of 2.1 dB and a $P_{1dB}$ of -18.6 dBm. The wireless transceiver system demonstrated a successful data transfer within a distance of 5 meters.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.1-6
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• 2011

In this paper, an 1.5Gbit/s wireless data transmission system using the carrier frequency of 300 GHz band was implemented. The RF front-end was composed of schottky diode sub-harmonic mixer, frequency tripler, and horn antennas for transmitter and receiver, respectively. The LO frequencies of sub-harmonic mixer are 150GHz for transmit chain and 156GHz for receive chain. The ASK(Amplitude Shift Keying) modulation was used in the transmitter and the envelope detection method was used in the heterodyne receiver. The conversion loss of sub-harmonic mixer and implementation system loss were measured to be 9.8dB and 1.2dB, respectively. The 1.5Gbit/s video signal with HD-SDI format was transmitted over wireless distance of 40cm without optical lens(4.2m with optical lens) and displayed on HDTV at the transmitted average output power of $20{\mu}W$.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.240-246
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• 2012

The Hilbert transform, which has been hitherto discussed in coherent imaging, is for the first time investigated in the context of incoherent imaging. Because the Hilbert transform of the information is superposed coherently with the original light field. We present a two-pupil optical heterodyne scanning system and analyze mathematically the design of its two pupils such that the optical system can perform the Hilbert transform on incoherent objects. In this paper, we review and formulate the definition of an analytic signal of a function and from which we can obtain the Hilbert transform of the function. and we analyze the design of pupils so as to obtain the Hilbert transform and show some 2-D simulations. Computer simulation results of the idea clarify the theoretical results.

• Journal of Astronomy and Space Sciences
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• v.27 no.2
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• pp.145-152
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• 2010

In this paper, we developed a local oscillator (LO) system of millimeter wave band receiver for radio astronomy observation. We measured the phase and amplitude drift stability of this LO system. The voltage control oscillator (VCO) of this LO system use the 3 mm band Gunn oscillator. We developed the digital phase locked loop (DPLL) module for the LO PLL function that can be computer-controlled. To verify the performance, we measured the output frequency/power and the phase/amplitude drift stability of the developed module and the commercial PLL module, respectively. We show the good performance of the LO system based on the developed PLL module from the measured data analysis. The test results and discussion will be useful tutorial reference to design the LO system for very long baseline interferometry (VLBI) receiver and single dish radio astronomy receiver at the 3 mm frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1013-1022
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• 2010

In this paper, we propose a C-band radiometer for remote sensing of land surface temperature and present its experiment results using asphalt as target. Total power type is selected for high sensitivity and low power consumption, super-heterodyne type is selected for stable high gain. A radiometer designed at 5.1 GHz to have operating bandwidth of 110 MHz has system gain of 59 dB, noise figure of 2.7 dB and receiving sensitivity of 0.45 K. We have measured surface temperature on asphalt by using implemented system and thermometer. Analysis data of each measurement results show that a radiometer operates linearly with output voltage variation rate of 6 $mV/^{\circ}C$. As a result, we verified validity of a developed C-band radiometer for remote sensing of land surface temperature.