• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.1048-1058
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• 1996

In this paper, a small duplexer is designed and implemented using a H-plane T-junction and Transmitting/Geceiving filte with a dual mode cavity resonator for Ku-band. Transmitting(TX) filter is designed at center frequeny 12.5 GHz and Receiving(RX) filter, at center frequency 14.5 GHz. Both filters have a 100 MHz bandwidth. This duplexer is reduced to about 40% by the conventional duplexer of cavity bandpass filter structure in size. Operating characteristics of duplexer is optimized in order not to distors matching characteristics of each filter when interfaced to a H-plane T-junction. Consequently, the responses of filter with H-plane T-junction nearly coincide with that of filter itself.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.83-90
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• 2001

Conventional SAW duplexer filters employ a 1/4 wavelength transmission line, which causes difficulty in fabrication of the strip line on the package. Its manufacturing process is also complicated, because it needs integrating process of the separate transmitting filter, receiving filter and isolation circuits. This paper concerns development of a new structure of the duplexer filter that has all the transmitting filter, the receiving filter and the isolation circuit as a one chip device. For composition of the duplexer, we design the component SAW ladder filters and the isolation network consisting of lumped inductor and capacitor elements. Performance of the whole duplexer is optimized by the nonlinear multivariable minimization of a proper target function, and the result is compared with that of commercial filters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.975-983
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• 1998

A duplexer filter operating at 1.9 GHz band for personal communication system is designed and fabricated using $lambada$/4 TEM mode dielectric resonator. The transmitting band pass filter is designed in the type of the elliptic function band rejection filter by 3 dielectric resonators with 5 additional capacitors and 3 inductors. The receiving band pass filter is designed by 3 dielectric resonators with 5 additional capacitors which give additional series resonance. The parameters which are evaluated by design theory are practically applied to the duplexer filter construction and the simulation.

• 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.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.202-206
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• 2001

In this paper a novel dielectric resonator (DR) bandpass filter (BPF) with flexible arrangement of attenuation poles is proposed. This DR filter is similar to a conventional DR filter except adding a microstrip line below a DR, which not only shifts the location of attenuation poles, but also improves skirt characteristics. The duplexer with the proposed DR BPF has been yielded better isolation and sharper skirt behavior than that with a conventional DR alter. The implemented duplexer has shown a good performance and been well agreed with the simulation.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.150-154
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• 2003

In this letter, a novel compact duplexer which consists of Tx and Rx Filter using microstrip line ${\lambda}/4$ resonators with a pair of tap-connected open-ended stepped impedance stubs is designed. The tapped open stubs not only work as K-inverters but also introduce attenuation poles, attenuation poles are located at upper and lower side of the passband by adjusting the open stub length and width. The result of measurement duplexer has been yielded better isolation and sharper skirt behavior than that with a conventional bandpass filter and similar to those of simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.10
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• pp.958-963
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• 2013

Ceramic dielectric waveguide duplexer was developed. Duplexer was designed in order to minimize the muture interferences between transmission port and receive port of bandpass filter. The design method for antenna port was determined by the transmission loss and calibrated the length of resonator of recriving filter. We used the ceramic powder of dielectric constant 9.46 and installed SMD type on PCB board.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.393-396
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• 2000

Repeater Duplexer of 800MHz band consists of 4pole transmitter band pass filter, receiver band pass filter and branch circuit. Circuit parameter of Duplexer such as coupled capacitance of equivalent circuit was drawn out and used to coupled line characteristics impedance (Zoo, Zoe) that satisfied resonator condition and attenuation condition. Simulation was carried out by the ADS(Advanced Design System) were obtained good attenuation characteristics (869~894MHz： 65㏈(Min.),824~349MHz： 65㏈(Min.)

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.3-14
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• 2003

광대역 초고속 통신의 필요성으로 밀리미터파 대역에서 사용 가능한 소자들에 대한 관심이 높아지고 있다. Nonradiative dielectric(NRD) 도파로는 밀리미터파 대역에서 마이크로스트립에 비하여 전파손실이 적고, 금속 도파관에 비하여 집적화에 유리한 장점을 가지고 있다. 이에 밀리미터파 대역의 각종 소자에 사용 가능한 NRD guide에 대한 관심이 높아지고 있다. 본 고에서는 이러한 NRD 도파로를 이용한 대역통과 여파기 및 duplexer의 설계 방법과 EM simulation을 이용한 보정 방법, 그리고 기본적인 형태로부터 응용된 여러가지 형태의 filter 및 duplexer의 특성을 보이고 비교하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.169-172
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• 2002

In this paper, the design formulas for bandpass filters using parallel coupled stepped impedance resonators(SIR) are derived. General content about basic feature of stepped impedance resonators(SIR) is represented. The filters and duplexer using stepped impedance resonators(SIR) have been designed and realized with the presented design method at IMT-2000 frequency band Simulations have used serenade circuit simulation and HFSS EM-simulation. We were showed excellent agreements between SIR design theory and simulation results on the multi-layer filter/duplexer.