• 전자공학회논문지 IE
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• v.45 no.4
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• pp.1-6
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• 2008

A fast-hopping frequency synthesizer that reduces complexity and power consumption is presented for MB-OFDM UWB applications. The proposed architecture uses 3960 MHz LC VCO, 528 MHz ring oscillator, passive mixer and LC-tuned Q-enhancement BPF to generate Band Group 1 frequencies. The adjacent channel rejection ratio is less than -40 dBc for 3432 MHz and -H dBc for 4488 MHz. A fast switching SCL-tpre MUX is used to produce the required channel output signal and it takes less than 2.2 ns for band switching. The total power consumption is 47.9 mW from a 1.8 V supply.

• 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 electromagnetic engineering and science
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• v.17 no.1
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• pp.34-38
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• 2017

In this paper, we propose an active tunable bandpass filter (BPF) for efficient spectrum sensing in the TV White Space (TVWS) band. By designing a narrow bandwidth, it is possible to improve the sensing probability. The basic circuit configuration involves switching the PIN diode compromising capacitor bank to change the capacitance of the LC resonant circuit. To cover the whole TVWS band effectively, we add a varactor diode, and the bandwidth is set to 25-MHz. We improve the insertion loss by using the active capacitance circuit. The tunable BPF in the TVWS band with a 20-MHz interval is designed to have 11 channels with a bandwidth of 25 MHz and a low insertion loss of 1.7-2.0 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.76-80
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• 2011

This paper has proposed a 3~5 GHz low-power and wideband LNA(Low Noise Amplifier), which has been implemented in a 0.18-${\mu}m$ CMOS technology. The proposed LNA has basically the noise-cancelling topology to achieve a balun-function, wideband input matching, and relative low noise figure. In addition, it has utilized a 2nd-order LC-band-pass filter(BPF) as its output load to achieve higher power gain and lower noise figure with the lowest dc power consumption among previously reported works. The proposed amplifier consumes only 3.94 mA from a 1.8 V supply voltage. The simulation results show a power gain of more than +17 dB, a noise figure of less than +4 dB, and an input IP3 of -15.5 dBm.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.9-17
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• 1998

BiNbO$_{4}$ ceramics with 0.07wt% V$_{2}$O$_{5}$ and 0.03wt% CuO (BNC3V7) sintered at 900 .deg. C where it is possible for these to be co-fired with ag electronde. Dielectric constant of 44.3 TCF (Thermal Coefficient of resonance Frequency) of 2 ppm/.deg. C and Qxf value 22,000 GHz can be obtained from BNC3V7. the laminatedchip LC filter is indispensible to the minimaturization of PCS (Personal Communication System) terminals. Therefore, multilayer type BPF has been fabricated by screen-printing with silver electrode after tape casting. The simulated characteristics of the fabricated filters sintered at 900.deg. C werecomparedwith the designed ones. for Band Pass Filter widths was similar that ofdesigned ones. For Low Pass Filter (LPF), insertion loss value of band pass widths (2.4 dB) which is a few higher than that of designed (1dB), but characteristization of band pass widths was similar that of designed ones.s.of designed ones.s.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1666-1667
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• 2011

본 논문에서는 CSRR을 이용하여 0.5~1.5GHz 대역의 광대역 필터를 최적 설계 연구 하였다. Metamaterial의 일종인 CSRR은 LC 공진기 역할을 하며 전송선로와 결합하여 필터 특성을 나타낸다. 또한 높은 Q-factor의 특성을 갖기 때문에 협대역 대역통과 필터 특성을 갖는다. 이에 본 논문에서는 CSRR을 이용하여 광대역 대역통과 특성을 갑기 위해서 전송선로의 형태를 변형하고 진화알고리즘중 하나인 진화 전략기법을 이용하여 단일 셀의 최적 설계를 수행하였다. 이후 단위 셀을 다단으로 연결하여 최종 광대역 필터를 설계하였다. 본 논문에서 설계된 광대역 필터는 0.5~1.5GHz의 대역폭을 갖으며 00~00dB의 삽입손실을 갖는다. 그리고 저지대역에서 00~00dB의 저지 특성을 갖는다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.188-192
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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. The bandpass filter size is $2.0 mm{\times}1.2 mm{\times}0.8 mm$. Positioning of attenuation polefrequency, importance parameter for a performance of filter, is discussed using even-odd mode analysis by tuned capacitance of coupling capacitor and those results is implemented to LTCC filter circuit. Measured filter performances show that the insertion losses are -4.5dB, -4.1dB at 2.45GHz, 2.75GHz and the return losses are -8.5dB, 8.7dB.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.44-47
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• 2016

In these days, interest of systems and services using TVWS(TV White Space) are increased, communication systems and services for TVWS have been actively studied. The unoccupied frequency in TVWS is different according to the geographical location and the time of day. RF systems having a frequency tunable bandpass filter operated in TVWS could be efficiently used. In this paper, a frequency tunable bandpass filter operated in 470 ~ 698MHz is designed and implemented. In consideration of simple control and physical size, the tunable bandpass filter is designed with 2-pole. The implemented tunable bandpass filter has the operating frequency band of 470 ~ 698MHz with control voltages of 1.58 ~ 3.93V, the insertion loss of maximum 4.78dB and the return loss of below 10dB. The implemented frequency tunable bandpass filter can be directly used in the RF receiver for TVWS and the design procedures could be used for developing a high power tunable bandpass filter as the basic research data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.59-60
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• 2018

In this paper, we studied a design method for a band-pass waveguide filter with a modified H-type resonant iris (RI) placed in a thin transverse wall of a rectangular waveguide. The horizontal straight gap at the center of a conventional H-shaped iris is modified to a U-shaped one to increase the equivalent capacitance, and the equivalent inductance is improved by changing the vertical two straight slots into C-shaped ones. A third-order band pass filter using the proposed modified H-shaped iris was designed and, it was observed that the filter operated in the frequency range of 9.22-9.75 GHz with its insertion loss of 0.5 dB and return loss of 17 dB.