• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.65-70
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• 2012

In this paper, a compact UWB (Ultra Wideband) BPF(Band-Pass Filter) with dual notched bands is proposed using a hybrid Composited Right-Left Handed (CRLH) and Defected Ground Structure (DGS). To avoid the interferences such as Wireless LAN (Center frequency: 2.4GHz and 5.8GHz), the CRLH is employed to obtain the dual notched bands and the DGS is used to obtain the wide stop-band above the pass-band. The fabricated filter has good performance and has more than 30dB rejection at the center frequency of 2.4 GHz and 5.8GHz. The dual notched bands are easily movable by changing the CRLH parameter. Also the insertion loss is less than 0.4dB in the lower pass-band and 0.7dB in the upper pass-band, and it has small group delay variation less than 0.6ns. The size of the fabricated filter is very compact (17mm*17mm).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.959-966
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• 2006

This paper proposes a new concept about dual band predistortion linear power amplifier(PD LPA) using diplexer for digital cellular ($f_o$=880 MHz) and IMT-2000($f_o$=2,140 MHz) base stations. The diplexer is composed of low pass filter having defected ground structure(BGS) microstrip line and high pass filter having high-Q lumped capacitors and distributed elements. The proposed predistorter adopts a reflection type intermodulation signal generator with 3 dB hybrid coupler for good reflection characteristic. for a forward link one carrier CDMA IS-95A 1FA and WCDMA 1FA signal, the proposed dual band PD LPA shows the adjacent channel leakage ratio(ACLR) improvement about 10 dB and 9.36 dB for digital cellular and IMT-2000 band, respectively.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1279-1280
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• 2015

본 논문은 저전력 센서를 위한 무선 전력 수신 시스템을 설계하여 Wake-up 회로에 응용함으로써, 유효 신호의 입사 시에만 동작되는 수신기 시스템을 제안하였다. 제안 된 시스템은 기존 여파기를 DGS(Defected Ground Structure) 형태로 설계하여 소형화에 기여하였으며 여파기는 다이오드에 의해 생성되는 고조파 신호의 제거와 DC 통과의 역할을 수행하게 된다. 설계된 Rectenna의 변활 전력을 이용하여 수신기 시스템 스위치의 온, 오프를 조절함으로써 저전력 센서 수신 시스템의 동작 여부를 평가하였다. 제안된 시스템은 신호 수신 여부에 따른 저 잡음 증폭기와 데이터 복조의 동작 여부로 성능이 평가되었으며 우수한 동작 성능을 나타내었다.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.100-105
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• 2016

We have designed a three-channel output multiplexer (OMUX) using a band-pass filter and an ultra-wideband (UWB) antenna. The proposed band-pass filter is composed of an inner rectangular loop, an outer open stub, and a defected ground structure. The outer open stub can be used to control the pass band, and the inner rectangular loop can improve the insertion loss characteristics of the band-pass filter. The proposed band-pass filter, UWB antenna, and OMUX are fabricated and measured. The designed OMUX can cover the band group 1 (3,168-4,752 MHz) of WiX system. The measured radiation patterns are close to those of a conventional dipole antenna and the measured antenna gain varies from 1.8 dBi to 3 dBi over the operating frequency range.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.11
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• pp.34-39
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• 2002

In this paper, we proposed novel photonic bandgap(PBG) structure using EGP(Elevated Ground Plane) and via in ceramic substrate of microstrip line. From analysis result, the proposed PBG structure is reduced 52.5% at size and increased 45 % at bandwidth compared to typical planar PBG structure. It is also reduced 32 % at size and improved more than 8 dB at power loss compared to typical multilayer DGS(Defected Ground Structure). The proposed PBG structure also can be used bandstop and lowpass filter and it will be useful for small microwave integrated circuit and module development.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.682-690
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• 2012

In this paper, a highly linear self oscillating mixers(SOM) using second harmonic injections are presented. The H-slot defected ground structure(DGS) is designed as a balanced resonator for oscillation in the proposed SOM. Since the H-slot DGS resonator achieves a high Q factor, it is a suitable structure to provide low phase noise for the oscillator. The single balanced mixer is utilized in this work and it provides good LO-RF isolation since balanced LO signals are suppressed at the RF input port. In order to inject the second harmonic of the IF, we propose two different methods using feedback loops. In the first method, IF achieves a 3.08 dB conversion gain at 226 MHz with input power of -20 dBm at 5 GHz RF input signal. The IF achieves 2 dB conversion gain at 423 MHz with the input power of -20 dBm at 5.2 GHz RF input signal in the second method. The measured IMD3s are 61.8 dB and 65 dB for the each method. These SOMs present improved linearity compared to that without the second harmonic injection because IMD3s are improved by 18. dB and 21 dB for each method.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.475-482
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• 2019

In this paper, we propose a triple band antenna for GPS / DCS / WLAN system. The proposed antenna has the characteristics required by considering the interconnection of two strip lines and various slits on the ground place. The total substrate size is $31mm(W1){\times}50mm(L1)$, thickness (h) 1.6 mm, and the dielectric constant is 4.4, which is made of $22mm(W7+W12+W8){\times}43mm(L4+L3)$ antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 340 MHz (1.465 to 1.805 GHz), 480 MHz (2.155 to 2.635 GHz) and 1950 MHz (4.975 to 6.925 GHz) were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency triple band as required.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.75-80
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• 2006

This paper has proposed a novel dual band transmitter module which can be operating either as an amplifier or as a frequency multiplier according to the input frequency. A conventional dual band transmitter consists of separate amplifiers operating at each frequency band, but the proposed dual band module operates as an amplifier for the IEEE 802.11b/g signal, and as a frequency doubler for the IEEE 802.11a signal according to input frequency and bias voltage. In this paper, we have obtained sharp stop band characteristics by using microstrip DGS(Defected Ground Structure) to suppress the fundamental frequency of the frequency doubler as well as the second harmonic of the amplifier. From measurement result, second harmonic suppression is below -59dBc in the amplifier mode, and fundamental suppression is below -35dBc in the frequency doubler mode. And the designed module has 17.8dBm output P1dB at 2.4GHz and 10.1dBm power for 5.8GHz output, and the output power in the two modes are 0.8dB and 2.8dB larger than the module with ${\lambda}g/4$ reflector, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2541-2548
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• 2010

This paper describes the calculation for characteristic impedance of transmission line with periodic structures such as defected ground structure (DGS) and photonic bandgap (PBG). The previous method which uses the ${\lambda}$/4 transmission line model is reviewed and its disadvantage that the calculated characteristic impedance is strongly dependent on the frequency is discussed. The characteristic impedance of transmission lines with periodic structures are calculated using the ${\lambda}$/4 transmission line model and analytic method. The calculated characteristic impedance by the latter method is an almost constant value while that from the first method depends on the frequency strongly. In addition, the characteristic impedance of the transmission line with PBG is calculated and proposed, while it has been rarely studied ever. S-parameters are obtained from the measurement using the fabricated sample as well as simulation, and used for calculating the characteristic impedances and comparison. The characteristic impedances calculated from the measured S-parameters agree well with the simulated results. It is well described that the analytic method to calculate the characteristic impedance of transmission lines on uniform dielectric structures can be applied successfully to the transmission lines with periodic structures such as DGS and PBG.