• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.182-185
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• 2003

Error performance of two modulation schemes of millimeter-wave over fiber (MMoF) system i.e., optical double side band (ODSB) and optical single side band (OSSB) modulations is analyzed under Rician fading. Bit error rates (BER) of two detection techniques i.e., coherent and noncoherent detection are also compared in Rician fading. In aspect of error performance, ODSB modulation scheme has better BER than OSSB modulation scheme has under Rician fading. On the other hand, OSSB modulation scheme is advantageous in case of considering high bandwidth efficiency and small power degradation. Coherent detection technique is proper in Rician fading, because coherent detection provides more SNR gain whether fading is serious or not. Noncoherent detection can be applied when we need a simple receiver structure.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.417-420
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• 2001

In this paper, a transceiver using waveguide modules for 60 GHz band wireless LAN is implemented and analyzed. The characteristics of millimeter-wave transmitter are 0 dbm output power, 10.5 dB gain and 38 dBc spurious emition. The receiver's are 3.16 dB noise figure, 8.8 dB gain, -86dBm sensitivity. Maximum communication distance is more than loom. Intermediate frequency comply with IEEE 802.11b. The transfer of multimedia files is performed. The transceiver's data rate can vary with intermediate frequency bandwidth and the transceiver is designed more than 200 Mbps.

• Journal of Advanced Navigation Technology
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• v.2 no.1
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• pp.11-21
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• 1998

There have been active research efforts in the development of a dual-use millimeter-wave radiometer as an aircraft landing aid in low visibility conditions. In this paper, we constructed a radiometer operating at the Ka-band where it is relatively easy to build RF components. The radiometer is used to collect radiometric signatures of some vehicles and land surfaces. Measured signatures suggest that vehicles with metallic surfaces yield signatures markedly different from nearby land surfaces so that they can easily be detected by a simple radiometer.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.77-80
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• 2003

We design the local oscillator system of the 100 GHz band radio receiving system for a cosmic radio observation. We use the YIG oscillator with digital driver which is the main oscillator. This oscillator has a good frequency and phase stability at some temperature variation, and the easy computer aided control characteristics. This total system designed to two subsystem, first is the oscillator system include YIG oscillator, tripler, harmonic mixer and triplexer etc., second is the PLL system to supply the precise and stable local oscillator frequency to mixer. The proposed local oscillator system in this paper can be use a single or multi pixel receiver because this system can be lock the local oscillator frequency automatically using PC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.1057-1062
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• 2000

Allow me to introduce the development of an FM transmitter. The transmitter uses millmeter waves at the frequency of 60 GHz, and it can produce as much as 20 mW power with the band width of 1 GHz. The great feature of the FM transmitter is that it has been created by the special technique of utilizing the NRD (non radiative dielectric) waveguide. The advantage of adopting the NRD waveguide is that it can significantly reduce transmission loss. We can construct a small-size NRD guide transmitter in a simple way that has superb transmission performance. The NRD guide transmitter is very useful for CATV transmission or transmission over a wide range. In addition, the transmitter has almost the same band width as optical communication, and the data transmission speed of the transmitter is faster than that of optical communication. A transmitter with these merits would be highly appreciated as a way of ultra-highspeed communication network over short distances.

• Vacuum Magazine
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• v.4 no.4
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• pp.4-13
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• 2017

Quantum structures containing nanoparticles have attracted much attention because of their promising potential applications in electronic and optoelectronic devices operating at lower currents and higher temperatures. The quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. The Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimeter. The emission and absorption spectra corresponding to the energy band gap of the quantum dot is governed by quantum confinement principles in an infinite square well potential. The energy band gap increases with a decrease in size of the quantum dot. In this review paper, we will discuss the quantum dot and their application.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.64-72
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• 2005

In this paper, we propose a design method of the millimeter-wave(W-Band) waveguide cavity harmonic voltage controlled oscillator(VCO) using a Gunn diode for the armor sensor. Using the 3-dimensional simulation tool(Ansoft $HFSS^{TM}$), we were able to find the impedance matching point between waveguide and Gunn diode and estimate the oscillation frequency. A varactor diode is used for the frequency tuning, and we find out the equation for the calculation of the tunable frequency range. The designed VCO shows good performances; 17dBm output power at 94GHz center frequency, 520MHz frequency tuning range similar to the estimated value(480MHz).

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.345-353
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• 2013

A W-band Orthomode Transducer (OMT) has been developed for Korean VLBI Network (KVN) polarization observation. The OMT design was based on E-plane split-block technique using septum structure. 3-dimensional electromagnetic simulation was fully employed to optimize the performance of the OMT. Measurements of the fabricated OMT show that the return losses for the vertically and horizontally polarized modes are better than -20 dB across 80 ~ 108 GHz and the insertion losses for the both modes are less than 0.47 dB. The cross-polarization level of the OMT is less than -30 dB. The bandwidth of the developed OMT is estimated as around 30%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.883-889
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• 2006

In this paper, parasitic resonance modes generated in a conductor backed coplanar wave guide(CBCPW) and stripline band pass filter(BPF) and the oscillation phenomena of a 40 GHz power amplifier module(PAM) are analyzed and several methods to suppress them are presented for low-temperature co-fired ceramic(LTCC) based millimeter-wave RF System-in-Package(SiP) applications. Parasitic rectangular wave guide(RWG) modes of the CBCPW structure are completely suppressed in the operation frequency band by decreasing the distance between its vias and by increasing the mode frequency. In the stripline structure, RWG resonance modes are clearly eliminated by removing some vias facing each other and by placing them diagonally. In the case of the 40 GHz PAM, in order to reduce a cross talk due to radiation that is generated from interconnection discontinuities, high isolation structures such as embedded DC bas lines and CPW signal lines are used and then the oscillated PAM is improved.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.261-268
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• 2016

In this paper, dual-polarized monopulse cassegrain antenna for W-band millimeter-wave seeker was proposed and the performances were verified by the measured results of the fabricated antenna. Dual-polarized monopulse Cassegrain antenna consists of main/subreflector, dual-polarized feed horn and monopulse comparator. The proposed feed horn has $2{\times}2$ array square waveguide feeding structure to make monopulse signals and it was designed using 90 degree rotational symmetric structure to receive dual-polarized signals. At the sum and difference channel, the measured vertical and horizontal polarization radiation pattern were similar. Measurement gains are 35.1 dBi for v-pol. and 35.6 dBi for h-pol. at the center frequency with 0.5dBi difference between each polarization and the side lobe level is below -21.6 dB.