• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.38-46
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• 1996

The purpose of this study is to develop the miniaturized duplexer filter for mobile communications using high dielectric constant (${\varepsilon}$r > 100, 180) ceramic resonators. Duplexer filter was ocmposed of ceramic resonators which has been developed using BNT system and SCT system, respectively. Developed duplexer filter was formed to have Tx frequency band at 836.5 (($\pm$12.5)MHz and Rx frequency band at 881.5 ($\pm$12.5)MHz. Insertion loss at Tx frequency band was 1.41dB and 1.46dB, insertion loss at Rx frequency band was 3.49dB and 3.65dB, respectively. Especially, duplexer filters using dielectric cermaics with ${\varepsilon}$r = 180 were 8% smaller than commercially manufactured duplexer filters using dielectric ceramics with ${\varepsilon}$r = 90 by murata.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.78-83
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• 1996

A timing recovery circuit of 10 Gbit/s optical receiver is described. The circuit consists of a passive NRZ-to-PRZ circuit, a dielectric resonator filter (DRF) and a narrow band amplifier, which for the first time adopted a temperature compensation technique using the tempareature characteristics of DR. The experimental results showed an output clock phase variation of less than ${\pm}$6 degree over the operating temperature range form 0$^{\circ}C$ to 75$^{\circ}C$ and measured maximum rms jitters of less than 2 phs with the resonance detunings of up to ${\pm}$10 MHz. These experimental results show that the circuit is a suitable for 10 Gbit/s lightwave transmission system.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.128-132
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• 2017

In this thesis, a BPF(band-pass filter) at the center frequency of 2.14GHz, and bandwidth of 20MHz is designed and implemented using high Q dielectric resonators with ${\varepsilon}_r=38$. The DR(dielectric resonator) is resonated by $TE_{01{\delta}}$-mode and it has a hole in the center of DR. The BPF consists of 6-poles dielectric resonators and the characteristic of elliptic function is obtained by non-adjacent coupling. It has the average insertion loss of 0.97dB and the return loss over 25dB in its passband. In this thesis, the frequency selectivity is more improved by the coupling characteristics between non-adjacent resonators than that of dielectric resonator filters with a Chebyshev response.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.613-619
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• 1994

Dielectric properties of Ba(ZnS11/3TTaS12/3T)OS13T+x ZnO(x=0, 0.4, 0.8, 1.0 wt%) ceramics have been investigated at microwave frequencies. With excess ZnO, the sinterability was improved and the dielectric constant($\varepsilon$S1rT) and the unloaded quality factor(QS1UT) were increased. The structure changed into hexagonal from pseudocubic as being annealed at 140$0^{\circ}C$ in excess ZnO composition. Also, the temperature coefficient of the resonant frequency ($\tau$S1fT) turned into (-)ppm/$^{\circ}C$ when sintered at 155$0^{\circ}C$ for 2 hours. But the specimen sintered in ZnO muffling showed increased density and $\varepsilon$S1rT but lowerde QS1uT. Among the specimen investigated, expecially the composition added with 0.4wt% excess ZnO showed the most optimum dielectric values ($\varepsilon$S1rT=28, QS1uT x f=120000GHz) better than those of original Ba(ZnS11/2T TaS12/3T)OS13T ceramics.

• ETRI Journal
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• v.14 no.4
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• pp.217-227
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• 1992

최근 이동통신 및 위성통신 등 마이크로웨이브를 이용하는 통신분야의 시장이 급속히 신장됨에 따라 RF(Radio Frequency) 부품의 산업적 중요성이 부각되고 있다. RF 부품은 크게 능동부품과 필터로 대표되는 수동부품으로 대별되는데, duplexer나 필터는 현재 대부분 마이크로웨이브 세라믹유전체를 사용 제조하고 있다. 본 연구에서는 이들 부품들에 사용가능한 세라믹유전체를 개발하기 위한 연구의 일환으로 BaO-$Sm_2$$O_3$-$TiO_2$계 세라믹의 마이크로웨이브 유전특성과 여기에$La_2\$$O_3$를 첨가한 계인 BaO-($Sm_1$$-_X$$La_X$$)_2$$O_3$-$TiO_2$ 세라믹유전체를 제조하여 마이크로웨이브 유전특성을 살펴보았다. RF 부품에 사용되는 세라믹유전체는 높은 유전율$\varepsilon_r$높은 품질계수 (Q) 및 안정된 온도특성 $\tau_f$ 등의 조건을 충족시켜야한다. 본 연구에서는 유전체의 $\varepsilon_r$ 및 Q의 측정에 디스크형 유전체공진기와 두개의 도체평행판을 사용한 Hakki-Coleman법을 사용하였으며, $\tau_f$는 fixture를 항온조에 넣어서 측정하였다. BaO-$Sm_2O_3-TiO_2$계의 경우 소결온도 $1350^{\circ}C$까지는 $\varepsilon_r$및 Q가 증가하나 그 이상의 소결온도에서는 감소한다. 그리고 $\tau_f$는 $-35_{ppm}/^{\circ}C$에서 소결온도에는 거의 의존하지 않았다. $La_2O_3$를 첨가한BaO-($Sm_1$$-_X$$La_X$$)_2$$O_3$-$TiO_2$ 세라믹의 마이크로웨이브 유전특성은 $La_2O_3$의 첨가량이 많을수록 $\tau_f$값이 음에서 양으로 이동함이 관찰되었으며, x=0.15에서 $\tau_f$가 0이 되어 마이크로웨이브 부품용 마이크로웨이브 세라믹유전체를 얻을 수 있음이 확인되었다.

• Journal of Sensor Science and Technology
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• v.8 no.5
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• pp.407-413
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• 1999

The resonant frequency of dielectric rod resonator can be calculated very accurately by means of the concept of electric and magnetic walls from the symmetry. But in a real situation, when the supporter is placed in the cavity, asymmetry appears due to the supporter and its dielectric constant. Then we need research into the resonance characteristic of asymmetric dielectric resonator. In this paper, for the dielectric rod resonator which is placed in the asymmetric position in the conducting cavity, the equation for resonance characteristic was derived and the resonant frequency was calculated with the eigenfunction expansion method. We found that the calculated resonant frequency is very accurate when it was compared with the experimental result and that asymmetry affects the resonant frequency more in TM mode than in TE or in hybrid mode.

• 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.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.274-283
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• 1997

These days, according to surprising development of communication enterprises, every soft of devices is getting smaller and cheaper. Among these Devices, microwave dielectric ceramics are studied and progressed briskly as the materials of dielectric resonator. Dielectric properties of BaO-S $M_{2}$ $O_{3}$-Ti $O_{2}$, one of the BaO Lnsub 2/ $O_{3}$-Ti $O_{2}$ (Ln=La, Sm, Nd, Pr…) system, synthesized by solid-reaction and coprecipitation method were investigated. Disk-type samples were sintered at 1250-1400.deg. C for 2hrs. As a result, single phase was not synthesized in both method. First created the second phase of S $M_{2}$ $Ti_{2}$ $O_{7}$, and then the last phase of $Ba_{3.75}$S $m_{9.5}$ $Ti_{18}$ $O_{54}$, Ti $O_{2}$, and $Ba_{2}$ $Ti_{9}$ $O_{20}$. When the sample was sintered at 1280.deg. C (in solid reaction method) and at 1310.deg. C (in coprecipitation method), it obtained highest dielectric constant (72.96 and 71.70, respectively) and high Q value. Above that temperature, dielectric constant and Q value decreased because of lattice defect according to oxygen vacancies........

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.2 s.7
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• pp.81-87
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• 2005

In this paper, a VCDRO(Voltage Control Dielectirc Resonator Oscillator) for signal source of doppler radar system is designed and fabricated. The proposed VCDRO is made with new tuning mechanism using CPW line. The coplanar waveguide of $\lambda_{g}$/2 in length with varactor diode is placed on the metallization side under the dielectric resonator and coupled to it. Tuning varactor diode is mounted at one end of the CPW. The proposed circuit tuned by a CPW allows one more varactor diode to be mounted on the optimized CPW, where a greater sensitivity of frequency tuning is needed. With varying the biasing voltage for the varactor diode from 0 V to 15 V, output frequency tuning of 12 MHz is obtained. The PLDRO exhibits output power of 16.5 dBm with phase noise in the phase locked state characteristic of -115 dBc/Hz at 100 Hz, -105 dBc/Hz at the 10 kHz, and -102 dBc/Hz at 1 Hz offset from 10.525 GHz , respectively.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.147-155
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• 2005

In this paper, we propose that three uniform coplanar waveguides(CPWs), such as a conventional, finite grounded(FG), and grounded(G) CPWs, can be coupled with a $TE_{01{\delta}}$ mode dielectric resonator(DR) for a parallel resonant characteristic as a microstrip line coupled with the DR. Coupling characteristics have been investigated by placing the DR on a dielectric support above the CPWs and by moving the DR away from the center of a slot of the CPWs to the ground plane. FEM simulation(HFSS) results in terms of S-parameters agree well with measurement results. Finally, unloaded Q values of the DR coupled with the three uniform CPWs are compared with those of the DR coupled with a microstrip line. The comparison shows that the DR coupled with the three CPWs has higher unloaded Qs than that coupled with a microstrip line and that the GCPW case has the highest unloaded Qs.