• Journal of electromagnetic engineering and science
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• v.17 no.3
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• pp.138-146
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• 2017

A phase-locked dielectric resonator oscillator (PLDRO) is an essential component of millimeter-wave communication, in which phase noise is critical for satisfactory performance. The general structure of a PLDRO typically includes a dual loop of digital phase-locked loop (PLL) and analog PLL. A dual-loop PLDRO structure is generally used. The digital PLL generates an internal voltage controlled crystal oscillator (VCXO) frequency locked to an external reference frequency, and the analog PLL loop generates a DRO frequency locked to an internal VCXO frequency. A dual loop is used to ease the phase-locked frequency by using an internal VCXO. However, some of the output frequencies in each PLL structure worsen the phase noise because of the N divider ratio increase in the digital phase-locked loop integrated circuit. This study examines the design aspects of an interconnected PLL structure. In the proposed structure, the voltage tuning; which uses a varactor diode for the phase tracking of VCXO to match with the external reference) port of the VCXO in the digital PLL is controlled by one output port of the frequency divider in the analog PLL. We compare the proposed scheme with a typical PLDRO in terms of phase noise to show that the proposed structure has no performance degradation.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.8-13
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• 2005

The InGaP/GaAs hetero-junction bipolar transistor(HBT) monolithic voltage-controlled dielectric resonator oscillator(VCDRO) is first demonstrated for a Ku-band low noise block down-converter(LNB) system. The on-chip voltage control oscillator core employing base-collector(B-C) junction diodes is proposed for simpler frequency tuning and easy fabrication instead of the general off-chip varactor diodes. The fabricated VCDRO achieves a high output power of 6.45 to 5.31 dBm and a wide frequency tuning range of ]65 MHz( 1.53 $\%$) with a low phase noise of below -95dBc/Hz at 100 kHz offset and -115 dBc/Hz at ] MHz offset. A]so, the InGaP/GaAs HBT monolithic DRO with the same topology as the proposed VCDRO is fabricated to verify that the intrinsic low l/f noise of the HBT and the high Q of the DR contribute to the low phase noise performance. The fabricated DRO exhibits an output power of 1.33 dBm, and an extremely low phase noise of -109 dBc/Hz at 100 kHz and -131 dBc/Hz at ] MHz offset from the 10.75 GHz oscillation frequency.

• ETRI Journal
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• v.30 no.2
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• pp.268-274
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• 2008

This paper proposes an open-loop clock recovery circuit (CRC) using two high-Q dielectric resonator (DR) filters for 39.8 Gb/s and 42.8 Gb/s dual-mode operation. The DR filters are fabricated to obtain high Q-values of approximately 950 at the 40 GHz band and to suppress spurious resonant modes up to 45 GHz. The CRC is implemented in a compact module by integrating the DR filters with other circuits in the CRC. The peak-to-peak and RMS jitter values of the clock signals recovered from 39.8 Gb/s and 42.8 Gb/s pseudo-random binary sequence (PRBS) data with a word length of $2^{31}-1$ are less than 2.0 ps and 0.3 ps, respectively. The peak-to-peak amplitudes of the recovered clocks are quite stable and within the range of 2.5 V to 2.7 V, even when the input data signals vary from 150 mV to 500 mV. Error-free operation of the 40 Gb/s-class optical receiver with the dual-mode CRC is confirmed at both 39.8 Gb/s and 42.8 Gb/s data rates.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.931-935
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• 2003

A multilayer two-stage LC bandpass filter using low-temperature cofired-ceramic(LTCC) is proposed in this paper. The proposed bandpass filter is composed of two ceramic substrates with different dielectric constant instead of single ceramic material from top to bottom layer. Inductive elements are designed in a low permitivity ceramic layer to reduce parasitic effects and loss, while capacitive elements are designed in a high permitivity ceramic layer for size reduction. The proposed filter has 950 MHz center &equency, 118 MHz tractional bandwidth, and 3.5 dB insertion loss. And, the total size of this filter is 2.5${\times}$2.5${\times}$l.4mm$^3$. The performance of filter is analyzed by changing coupling capacitance between each resonator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.492-498
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• 2003

In this paper, We analyze the optimum bias conditions of cascode coupled microwave mixer for maximum conversion gain mixer. Microwave self-oscillating mixer by two GaAs MESFET cascode coupled, to upper GaAs MESFET operating as a oscillator with high Q dielectric resonator and the lower GaAs MESFET operated as a mixer with low noise and high conversion characteristics. As a result of experiments, cascode coupled microwave self oscillating mixer according to optimun bias shows an 5.92 dBm oscillating power, -132.0dBc/Hz @ 100KHz at 5.15GHz and 3dB conversion loss.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.261-266
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• 2017

This study describes the design and implementation of SHF band Upconverter Digital Satellite Communication. The SHF band Upconverter unit consists of PLDROand frequency converter. In frequency converter, microstripBPF and LPF designed through the pre EMsimulation are implemented to minimize the unwanted spurious in frequency converter. Through the pre-simulation analysis ofspace environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Upconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Upconverter after production.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.283-287
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• 2003

Crystal structure of $(Ba_{1-x}La_x)[Mg_{(1+x)/3}Nb_{(2-x)/3}]O_3$ (BLMN) ceramics with $0{\leq}x{\leq}1$ was investigated using synchrotron X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). When La content, x, is above 0.1, the 1:2 ordered hexagonal structure found in $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BMN) was transformed into 1:1 ordered cubic structure. The 1:1 ordered cubic structure was maintained up to x=0.7. However, when x exceeded 0.7, BLMN was transformed 1:1 ordered structure which has cation displacement and in-phase and anti-phase tilt of octahedra.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.74-79
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• 2002

The EM(Engineering Model) VCO(Voltage Controlled Oscillator) is nonlinear designed for LO(Local Oscillator) of Ka-band satellite transponder. The microstripline coupled with dielectric resonator is implemented as a high impedance inverter to improve the phase noise, and the quality factor of resonant circuit can be transferred to active device with the enhanced loaded quality factor. The developed VCO has the oscillating tuning range of 9.7965~9.8032 GHz for the control voltage range of 0~12 V. This VCO requires the DC power of 8 V and 17 mA. The phase noise characteristics are -96.51 dBc/Hz @10 KHz and -116.5 dBc/Hz @100 KHz, respectively. And, the output power of 7.33 dBm is measured.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.103-109
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• 2004

In this paper, a new modeling methodology of thin film bulk acoustic resonator(TFBAR) is presented and the formulations of each lumped element in the model are also introduced. The new model is based upon the Mason model that is a reasonable model to explain the physical characteristics of unit TFBAR. After simplifying the modified Mason model with an additional dielectric loss term, the new model similar to Modified Butterworth-Van Dyke(MBVD) model is complete. The proposed model has three optimization variables which is half of the MBVD model. As a result, the curve fittings for the measured data are much faster and more accurate than any other conventional models. Moreover, it is very useful to design the bandpass filters or voltage controlled oscillators due to the design parameters, such as resonant and anti-resonant frequency, which can reflect the intentions of designer in the model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1313-1321
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• 2000

This paper presents a novel HTS microstrip pseudo-lumped element resonator for the compact and simple filter design. A 7-pole bandpass filter with quasi-elliptic response is designed and fabricated using non-adjacent couplings between resonators. A seven-pole quasi-elliptic filter is fabricated using double sided YBCO on a LaAlO$_3$ substrate with thickness of 0.5 mm and dielectric constant of 23.5. The filter has an insertion loss of 0.8 dB at 20K, a bandwidth of 8 MHz at the center frequency of 1774 MHz, and an attenuation of 33 dB for the cut-off-band of 1 MHz.