포크 형태의 개방형 스터브 및 SIR 구조를 이용한 이중대역 대역통과 여파기의 설계

이태현 한국ITS학회 2023 한국ITS학회논문지 Vol.22 No.1

This paper proposes a design of a dual-band band-pass filter that integrates a λg/2 open SIR structure, a transmission line, and a fork-type structure with symmetric and asymmetric open stubs. To obtain the dual-band effect, the proposed filter uses the SIR structure and adjusts the impedance ratio of the SIR structure. Therefore, the position of the harmonics of the filter is shifted through the adjustment of the impedance ratio, and this can obtain a double-band effect. In order to obtain the dual-band characteristics, the dual-band effect is obtained by inserting a open stub between the SIR structures with the SIR structure divided in half. In addition, the second frequency response is obtained by adjusting the length of the open symmetrical stub in the fork-shaped structure. The asymmetrical open stub in the fork form achieves optimum bandwidth by adjusting the length. Therefore, the first center frequency of the proposed band-pass filter is 5.896 GHz and the bandwidth is 13.6 %. At this time, the measurement results are 0.13 dB and 33.6 dB. The second center frequency is 5.906 GHz and the bandwidth is 13.6 %. At this time, the measurement results are 0.15 dB and 19.8 dB. The reason is that when the impedance ratio (Δ) is higher than 1, the position of the harmonic is shifted to a lower frequency band. However, if the impedance ratio (Δ) is lowered by one step, the position of harmonics will move to a higher frequency band. The function of the filter designed using these characteristics can be obtained from the measurement result. The proposed band-pass filter has no coupling loss and no via energy concentration loss because there is no coupling structure of input/output and no via hole. Therefore, system integration is possible due to its excellent performance, and it is expected that dedicated short-range communication (DSRC) system applications used in traffic communication systems will be possible. 본 논문은 λg/2 개방형 SIR 구조와 전송선로와 대칭 및 비대칭 개방형 스터브를 가진 포크- 형태의 구조를 일체화한 이중대역 대역통과 여파가 설계에 대해 제안을 한다. 이중대역 효과를 얻기 위해, 제안된 여파기는 SIR 구조를 이용했고, SIR 구조의 임피던스 비율을 조절한다. 그러므로 여파기의 고조파는 임피던스 비율의 조절을 통해 위치가 이동하게 되며 이는 이중대역 효과를 얻을 수 있다. 이중대역 특성을 얻기 위해 SIR 구조를 반으로 나눈 상태에서 SIR 구조 사이에 개방형 스터브를 삽입하여 이중대역 효과를 얻는다. 또한 포크 형태의 구조에서개방형 대칭 스터브의 길이를 조절함으로써 두 번째 주파수 응답을 얻는다. 포크 형태에서 비대칭 개방형 스터브는 길이의 조절을 통해 최적의 대역폭을 얻는다. 그러므로 제안된 대역통과 여파기의 첫 번째 중심 주파수는 5.896 GHz이며 대역폭은 13.6 % 이다. 이때, 측정 결과는0.13 dB 및 33.6 dB이다. 두 번째 중심 주파수는 5.906 GHz이며 대역폭은 13.6 % 이다. 이때, 측정 결과는 0.15 dB 및 19.8 dB이다. 그 이유는 임피던스 비율(Δ)이 1보다 높으면 고조파의위치는 낮은 주파수 대역으로 이동하게 된다. 그러나 임피던스 비율(Δ)이 1보 낮아지게 된다면고조파의 위치는 높은 주파수 대역으로 이동하게 될 것이다. 이러한 특징을 이용하여 설계된여파기의 기능은 측정 결과에서 얻을 수 있다. 제안한 대역통과 여파기는 입출력의 결합구조와 비아 홀이 없기 때문에 결합손실과 비아 에너지 집중 손실이 없다. 그러므로 성능이 우수하여 시스템 집적화가 가능하며 교통통신 시스템에서 활용되는 DSRC (dedicated short-range communication) 시스템 응용이 가능할 것으로 기대된다.

Simulation of band gap structures of 1D photonic crystal

R. L. Wang,J. Zhang,Q. F. Hu 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

We present a simple way to fabricate polyethylene methacrylate (PMMA) 1D periodic structures at the nanometer scale by using the calibrating sign of a digital scanning-electron microscope (SEM), and the transmission spectrum of a 1D photonic crystal consisting of PMMA layers and air layers with different incident angles of light was calculated by the transfer matrix method thus giving the photonic band- gap structures. It is found that the 1D photonic crystal appears to have a similar band gap structure both in TE and in TM mode, and the photonic band gap expands and the center wavelength of the forbidden bands blue-shifts with increasing incident angle of the light. This suggests that the larger the thickness of the medium layers forming the photonic crystal, the wider the photonic band gaps will be. We present a simple way to fabricate polyethylene methacrylate (PMMA) 1D periodic structures at the nanometer scale by using the calibrating sign of a digital scanning-electron microscope (SEM), and the transmission spectrum of a 1D photonic crystal consisting of PMMA layers and air layers with different incident angles of light was calculated by the transfer matrix method thus giving the photonic band- gap structures. It is found that the 1D photonic crystal appears to have a similar band gap structure both in TE and in TM mode, and the photonic band gap expands and the center wavelength of the forbidden bands blue-shifts with increasing incident angle of the light. This suggests that the larger the thickness of the medium layers forming the photonic crystal, the wider the photonic band gaps will be.

A 5kHz Bandwidth Low Noise Chopper-Stabilized Dual-Band Selective Filter SoC

김재빈,조종완,오태섭,이강윤 한국과학기술원 반도체설계교육센터 2021 IDEC Journal of Integrated Circuits and Systems Vol.7 No.2

In this paper, various blocks and structures applied to the low-noise 2 band selection band pass filter are described. In the proposed band pass filter when the frequency is input through the buffer, one of Band 1 or Band 2 can be selected using the switch, and the output goes through the buffer after the selected switch among Band 1 and Band 2. After the pre-amplifier, the low frequency band pass filter is used to secure -3 dB or more at 29.5 kHz (5 kHz range) and is used to secure -1 dB or more at 39.5 kHz (5 kHz range). The aim is to remove the interference between bands by -20 dB or more at the interference frequencies of 29.5 Hz and 39.5 Hz, which are the center frequencies of each band. Chopper structure was used to reduce noise, and it was designed to drop more than -21dB/√Hz in Band1,2.

Prediction of the Band Structures of Bi2Te3-related Binary and Sb/Se-doped Ternary Thermoelectric Materials

류병기,Bong-Seo Kim,이지은,Sung-Jae Joo,Bok-Ki Min,이희웅,Su-Dong Park,Min-Wook Oh 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.1

Density functional calculations are performed to study the band structures of Bi2Te3-related binary (Bi2Te3, Sb2Te3, Bi2Se3, and Sb2Se3) and Sb/Se-doped ternary compounds [(Bi1−xSbx)2Te3 and Bi2(Te1−ySey)3]. The band gap was found to be increased by Sb doping and to be monotonically increased by Se doping. In ternary compounds, the change in the conduction band structure is more significant as compared to the change in the valence band structure. The band degeneracy of the valence band maximum is maintained at 6 in binaries and ternaries. However, when going from Bi2Te3 to Sb2Te3 (Bi2Se3), the degeneracy of the conduction band minimum is reduced from 6 to 2(1). Based on the results for the band structures, we suggest suitable stoichiometries of ternary compounds for high thermoelectric performance.

절반의 X-슬롯을 가진 무선랜용 이중대역 모노폴 안테나

신동기 ( Dong-gi Shin ),이영순 ( Young-soon Lee ) 한국항행학회 2018 韓國航行學會論文誌 Vol.22 No.5

본 논문에서는 소형화를 위해 방사패치에 절반으로 절단된 X-슬롯을 가지며, WLAN 이중대역인 2.4 GHz 대역 (2.4 ~ 2.484GHz) 및 5 GHz 대역 (5.15 ~ 5.825 GHz)용 마이크로스트립 급전 모노폴 안테나를 제안하였다. 여러 파라미터들의 수치들을 최적화하여 주파수 특성을 만족하였으며, 5 GHz 대역의 반사손실 개선을 위해 DGS (defected ground structure)를 사용하였다. 제안된 안테나는 크기가 24 × 41 mm², 두께는 1.6 mm, 유전상수가 4.3인 FR-4 기판에 설계 및 제작 되었다. 제안된 안테나의 제작 및 측정결과, 임피던스 대역폭(S₁₁ ≤-10dB)이 2.4 GHz 대역에서는 약 450 MHz (2.27 ~ 2.72 GHz), 5 GHz 대역에서는 약 1340 MHz (4.79~ 6.13 GHz)인 대역폭을 얻어 제안한 두 대역의 IEEE 규격(IEEE 802. 11n)을 충분히 만족하는 안테나를 구현했다. 특히 두 대역에서 안정되고 비교적 좋은 무지향성 경향의 방사패턴을 얻을 수 있었으며, 각 대역에서의 안테나 이득은 각각 1.31, 1.98 dBi 임을 확인할 수 있었다. For the size reduction, we propose a microstrip-fed monopole antenna with half X-slot in the radiation patch and cover WLAN dual band 2.4 GHz band (2.4 ~ 2.484 GHz) and 5 GHz band (5.15 ~ 5.825 GHz). The frequency characteristics such as impedance bandwidth and resonant frequencies were satisfied by optimizing the numerical values of various parameters, while the reflection loss in 5 GHz was improved by using defected ground structure (DGS). The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 24 × 41 mm². The measured impedance bandwidths (S₁₁ ≤ -10 dB) of fabricated antenna are 450 MHz (2.27 ~ 2.72 GHz) in 2.4 GHz band and 1340 MHz (4.79 ~ 6.13 GHz) in 5 GHz band which sufficiently satisfied with the IEEE 802. 11n standard in dual band. In particular, radiation patterns which are stable as well as relatively omni-direction could be obtained, and the gain of antennas in each band was 1.31 and 1.98 dBi respectively.

Design of Grooved Microstrip Patch Resonator Filters for Mobile Communication

Vivek Singh Kushwah,Geetam Singh Tomar,Sarita Singh Bhadauria 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.5

In advanced communication technology the microstrip filter has an important job in terms of selectivity and elimination of the undesired signals. In microwave and RF frequency applications the design of filter is complex task as lumped components cannot be used in this range of frequency. Microstrip filters are always preferred over the lumped filters at larger frequency for their compact size, lighter weight, lower cost and higher performance. In this paper the design of grooved microstrip patch resonator band-pass filter is presented at mid-band frequency 1.8 GHz for L-Band applications. It also acts as a band-reject filter at center frequency 1.1 GHz, which is innovative concept in microstrip filter design. Band-pass filter has a high attenuation in stop band, small insertion loss of 0.5744 dB and high return loss of 26.52 dB in the pass band whereas Band-reject filter has a low attenuation, high insertion loss of 21.95 dB and low return loss of 0.2432 dB in the stop band. The result is encouraging and fabrication is also very easy.

Tuning the electronic band structure of PCBM by electron irradiation

Yoo, Seung Hwa,Kum, Jong Min,Cho, Sung Oh Springer 2011 NANOSCALE RESEARCH LETTERS Vol.6 No.1

<P>Tuning the electronic band structures such as band-edge position and bandgap of organic semiconductors is crucial to maximize the performance of organic photovoltaic devices. We present a simple yet effective electron irradiation approach to tune the band structure of [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) that is the most widely used organic acceptor material. We have found that the lowest unoccupied molecular orbital (LUMO) level of PCBM up-shifts toward the vacuum energy level, while the highest occupied molecular orbital (HOMO) level down-shifts when PCBM is electron-irradiated. The shift of the HOMO and the LUMO levels increases as the irradiated electron fluence increases. Accordingly, the band-edge position and the bandgap of PCBM can be controlled by adjusting the electron fluence. Characterization of electron-irradiated PCBM reveals that the variation of the band structure is attributed to the molecular structural change of PCBM by electron irradiation.</P>

재구성이 가능한 이중 대역 원형 편파기 설계

엄순영,이종문,신천식 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.7

In this paper, a reconfigurable dual-band circular polarizer structure is proposed. To implement the reconfigurable function of the circular polarizer, a pair of detachable cog-comb plates that determine circular polarization performance are attached to the outside of the circular waveguide. In order to verify the electrical performance of the proposed circular polarizer structure, a dual-band circular polarizer operated in Tx/Rx bands (Tx: 6.25~6.75 GHz, Rx: 3.70~4.10 GHz) is designed for application in the Korea augmentation satellite system Uplink Station (KUS) system. The axial ratio at the bore-sight of a conical horn antenna with an optimized dual-band circular polarizer in series shows good circular polarization performance of less than 0.99 dB at the Tx band and less than 1.50 dB at the Rx band. A lightweight manufacturing method for dual-band circular polarizers is also proposed.

LTE, ISM, WLAN에 적용 가능한 Arm 구조 삼중대역 안테나 최적 설계

이승제(Seung-Je Lee),오승훈(Seung-Hun Oh),이정혁(Jeong-Hyeok Lee),김형석(Hyeong-Seok Kim) 대한전기학회 2014 전기학회논문지 Vol.63 No.12

In this paper, we propose a design of a triple-band microstrip circular patch antenna. The proposed antenna generates the triple frequency resonance at 1.85GHz(LTE), 2.45GHz(ISM) and 5.5GHz(WLAN). Firstly, we design the dual-band antenna. The dual-band antenna consist of the circular patch, slits, and the slot. The circular patch and slot are designed for dual frequency of 2.45GHz and 5.5GHz, respectively. And then the dual-band antenna is combined with additional arm-shaped structure for the triple-band characteristic. The arm-shaped structure is operated as the dipole. It is designed for lowest frequency of 1.85GHz. Each part of the antenna unites to a new structure. In order to design the proposed antenna automatically and optimally, APSO algorithm is adopted. During APSO, the mismatch of the proposed antenna is resolved. The optimal designed antenna has an acceptable return loss(-10dB) at each bands(i.e, 1.85GHz, 2.45GHz and 5.5GHz).

Effects of crystal and electronic structures of ANb₂O₆ (A=Ca, Sr, Ba) metaniobate compounds on their photocatalytic H₂ evolution from pure water

Cho, I.S.,Bae, S.T.,Kim, D.H.,Hong, K.S. Pergamon Press ; Elsevier Science Ltd 2010 International journal of hydrogen energy Vol.35 No.23

Alkali-earth metaniobate compounds, ANb<SUB>2</SUB>O<SUB>6</SUB> (A = Ca, Sr, Ba), were prepared by the conventional solid-state reaction route and their electronic band structures and photocatalytic activities were investigated. The prepared powders were characterized using X-ray diffraction (XRD), field-emission electron microscopy (FE-SEM), UV-vis diffuse reflectance spectroscopy, and fluorescence spectroscopy. It was found that the particle sizes (∼1 μm) and BET surface areas (∼1 m<SUP>2</SUP>/g) of the metaniobate compounds were nearly identical. From the electronic band structure calculations, however, the band-gap energies of these metaniobate compounds were found to be in the order of CaNb<SUB>2</SUB>O<SUB>6</SUB> > SrNb<SUB>2</SUB>O<SUB>6</SUB> > BaNb<SUB>2</SUB>O<SUB>6</SUB>. These calculated band-gap energies were consistent with those estimated from the UV-vis diffuse reflectance spectra. Moreover, the conduction-band edge (reduction potential) of SrNb<SUB>2</SUB>O<SUB>6</SUB> calculated from the electronegativity data was higher than those of CaNb<SUB>2</SUB>O<SUB>6</SUB> and BaNb<SUB>2</SUB>O<SUB>6</SUB>. The photoluminescence spectra revealed that CaNb<SUB>2</SUB>O<SUB>6</SUB> exhibited a strong blue luminescence emission (at 300K), while no obvious emissions were observed in either SrNb<SUB>2</SUB>O<SUB>6</SUB> or BaNb<SUB>2</SUB>O<SUB>6</SUB>. The luminescence behaviors of these metaniobate compounds and their band structure variations originating from their crystal structures play an important role in their photocatalytic activity for the evolution of H<SUB>2</SUB> from pure water. SrNb<SUB>2</SUB>O<SUB>6</SUB>, which has a higher conduction-band edge potential than the other compounds, exhibited higher photocatalytic activity.