• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.653-658
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• 2015

In this paper, the Square Split Ring Resonator(: SRR) of Defected Ground Structure(: DGS), applicable to MMIC(: Monolithic Microwave Integrated Circuit) design, is proposed. The mathematical method to solve the equivalent parameter of the resonator from the measured results of resonator is introduced in this paper. To verify the method, SRR-DGS resonator with 2.95 GHz center frequency is fabricated, for measuring characteristics and calculating the equivalent parameter. The result from this process is compared with the data of the ADS simulation, and as a result both were identical.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.6
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• pp.1-4
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• 1975

This paper dells with the impedance variations of the IMPATT diode depending upon the small a.c. coomponent superimposed on the d.c. bias. The frequency deviation of the modulated wave is measured using a carrier null method on microwave spectrum analyser. Frequency modulation is achieved by the weack a.c. signal superimposed on the d.c. bias. The bandwidth rapidly increase with increasing modulation signal magnitude for constant modulation frquency and slightly decrease with decreasing modulation frequency for constant modulation signal magnitude.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.729-736
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• 2011

In this paper, we propose a varactor-diodeless voltage-controlled oscillator operating at X-band, and verify the possibility of applying to a receiver for microwave radar signal detection applications. The proposed VCO is realized by only single RF BJT device as a varactor diode is substitued by a intrinsic collector-base PN-junction of the active device which is used to generate negative resistance. The fabricated VCO meets the specification of the receiver, which has a 11.20~11.75 GHz tuning bandwidth with respect to the tuning voltage, 1.0~7.0 V, output power of 9.0~12.0 dBm and linear frequency tuning performance.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1219-1229
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• 2016

The present paper reports on a trial to shed further light on the characterization, applications, and operation of radar speed guns or Gunn diodes on different radiation environments of neutron or g fields. To this end, theoretical and experimental investigations of microwave oscillating system for outer-space applications were carried out. Radiation effects on the transient parameters and electrical properties of the proposed devices have been studied in detail with the application of computer programming. Also, the oscillation parameters, power characteristics, and bias current were plotted under the influence of different ${\gamma}$ and neutron irradiation levels. Finally, shelf or oven annealing processes were shown to be satisfactory techniques to recover the initial characteristics of the irradiated devices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2227-2235
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• 2009

This paper describes the system configuration and measured performances of a wireless power transmission system which utilizes microwave. The technically final target of this system is to provide DC power to various mobile terminals within limited spaces such as buildings, conference rooms, and so on. The prototype system is built using in-house designed and fabricated circuits such as microwave oscillator, high power amplifier, microstrip patch antenna, low pass filter, and detector/rectifier. The fixed RF power of 29.3dBm at 2.4GHz is produced from the high power amplifier and transmitted through the transmitting antenna, while the received RF power at the receiving antenna is transformed into DC power through the detector/rectifier. The measured change of DC voltage according to the distance between transmitting and receiving antenna is described.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.369-372
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• 2000

본 논문에서는 P-HEMT Gate-바이어스 튜닝에 의한 위상동기 마이크로파 발진기를 설계하였다. 설계된 유전체 발진기는 병렬궤환공진 형태로서 P-HEMT의 게이트단에서 전압을 제어하여 전압제어발진기 형태로 주파수를 가변시키므로서 안정된 위상동기신호를 나타나도록 하였다. 위상동기방식은 외부에서 제공되는 125㎒의 기준주파수를 SRD로 체배시켜 하모닉 신호를 이용한 마이크로파 샘플링 위상검파 방식으로 설계하였으며, 유전체 발진기의 자유발진신호와 샘플링 신호사이의 위상비교에 의하여 ±1㎒ 범위의 고안정 특성을 갖는 13.25㎓대역의 위상고정 발진기의 동기화와 저 위상잡음을 나타내었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.677-684
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• 2004

This paper presents direct T $M_{01}$-T $E_{11}$ small mode converter using circular waveguide with tilted structure for X-band high power system. It is designed to transmit microwave energy from Relativistic Backward-Wave Oscillator(RBWO) source to hem antenna effectively, with optimized geometry a parameter study The simulated and measured results of return loss, fractional power of each mode, impedance bandwidth and mode pattern are provided.d.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.861-863
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• 2003

In this work, the preparations and characteristics of capacitors and inductors for RF IC as a integrated devices are investigated. These kinds of capacitors and inductors can be applicable to the passive components utilized in voltage controlled oscillator(VCO), low noise amplifier(LAN), mixer and synthesizer for mobile telecommunication of radio frequency band(900 MHz to 2.2GHz), and in a library of monolithic microwave integrated circuit(MMIC). The results show that these inductors and capacitors array for RF IC may be applicable to the RF IC passive components for mobile telecommunication.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.139-144
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• 2009

A Doppler radar is a radar using the doppler effect of the returned echoes from targets to measure their radial velocity. To be more specific the microwave signal sent by the radar antenna's directional beam is reflected toward the radar and compared in frequency, up or down from the original signal, allowing for the direct and highly accurate measurement of target velocity component in the direction of the beam. In this paper, we designed the doppler radar composed of 10.5 GHz band DROs(Dielectric Resonator Oscillator), $90^{\circ}C$ branch line coupler, single balanced mixer and $4{\times}4$ array antenna of high gain, high directivity, for non-contact type hydrometer. Fabricated Doppler radar can detect slow moving objects.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.1
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• pp.74-81
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• 2004

We propose a novel scheme to transmit high center frequency RF signals using electroabsorption devices (EADs) as frequency converters at the transmitter and the receiver. In this approach frequency heterodyning is employed for obtaining high center frequency. With the EAD as a detector/mixer at the receiver we demonstrated a smaller conversion loss than that of the conventional modulator/mixer. With EAD as a modulator/mixer at the transmitter and with two heterodyned lasers to generate an optical local oscillator (LO), we demonstrated a large reduction (${\sim}23dB$) in conversion loss, and the transmission is not limited by the optical saturation of the EAD. This transmission scheme has optical single-side-band transmission feature which greatly relieves the fiber dispersion effect.