• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.9 no.3
• /
• pp.378-385
• /
• 1998

A three-dimensional finite difference time domain (3-D FDTD) algorithm of calculation for the characteristics of coaxial-to-cavity filter including a discended probe and a tuning post is presented. In the arrangement the inner coaxial conductor protrudes into the cavity and operates as a probe radiator. And the height of the rectangular tuning post determines the resonant frequency. The validation of this method is confirmed by comparing the calculated values with experimental results for the designed filter.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.7
• /
• pp.1032-1039
• /
• 2022

In this paper, we designed and implemented a cavity bandpass filter combined with a cross-coupling equalizer structure to enhance Group delay for 5G mobile network repeater, which can replace the SAW (Surface Acoustic Wave) type bandwidth filter used in the existing mobile communication system. Using the 3D EM simulation tool (HFSS), the resonance frequency, the coupling coefficient between resonators, and external quality coefficient between resonators were calculated. Based on this, a 12th bandpass filter was constructed to have attenuation characteristics of more than 20dB at the edge end of both sides of the band with a metal cavity structure with a frequency band of 3500MHz to 3600MHz and bandwidth of 97.85MHz. The designed bandpass filter satisfies the group delay time requirement for the 5G mobile communication standard and the in-band and out-band frequency responses.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.7
• /
• pp.26-31
• /
• 2005

In this paper, a small BPF(band pass filter) is designed using new probe type for wireless communication system. The dielectric resonator is used high Q ceramics for low loss characteristic. In order to provide a band pass filter which can be reduced in dimension, can be reduced in height, and can be surface-mounted. The filter was fabricated using $TE_{01{\delta}}$ mode dielectric resonator. The input/output probes are attached to coner portion of the rectangular metal cavity. Results of the manufactured filter($12{\times}12{\times}8[mm]$) show that the center frequency is 9.95358[GHz], the insertion loss is -1.9[dB], the 3[dB]_bandwidth is 14.9[MHz], and the loaf Q is 664.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1993.10a
• /
• pp.316-320
• /
• 1993

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.1
• /
• pp.49-60
• /
• 2017

In this paper, we presented the result of the study on high-power handling capability of the X-band circular waveguide cavity filter configured at the output of high power amplifier(120 W) for geostationary satellites. The dual mode circular waveguide cavity filter with 6th order is selected and the physical model of the filter is designed after determination of the size of resonator from mode chart. Multipactor margin analysis is performed by the SEM method and the VMF method. The result shows that the VMF method predicts lower multipactor breakdown thresholds than the SEM method. Evaluating the multipactor margin obtained by the VMF method to ECSS criteria, we could decide to perform multipactor test. The multipactor test conducted in ESA facility shows that multipactor did not occur even until the RF power increased up to 540 W. In consequence, by both analysis and test, we could verify that the X-band circular waveguide cavity filter has the sufficient high-power handling capability to operate on orbit.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.6
• /
• pp.169-173
• /
• 2014

In order to satisfy user's requirements of needs for various services and to efficiently use of frequency, a communication system using one platform can support many communication services. Tunable filters must be used in the front end of broadband communication systems which provide and support various communication methods. In this paper we design and implement a filter bank to verify the feasibility of cavity tunable filter with the operation frequency of 800 MHz ~ 1600 MHz. The filter bank is composed of five bandpass filters and each bandpass filter has the same operation frequency band of the tunable filter. The implemented filter bank has the maximum insertion loss of 0.326 dB, the bandwidth of 37 MHz ~ 84 MHz, and the attenuation of minimum 19.974dB and mximum 37.812dB at the band edge ${\pm}60MHz$ over the operating frequency band.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.12B
• /
• pp.1712-1723
• /
• 2001

This paper presents a design procedure and manufacturing techniques realizing of a 5.8 GHz duplexer based on cylindrical coaxial dielectric resonator. Upto Q$\times$f$\_$o/=30,000 cylindric coaxial dielectric resonator was developed control by addition of dielectric materials. This resonator shows attenuation characteristics -40 dB for transmitter and -50 dB for receiver by consisting of two sets of 4-stage cavity resonator within f$\_$o/$\pm$10 MHz bandwidth which was requirement of DSRC. Employing the measurement results, design procedure to characterize the transmission and reflection properties are presented.

• Journal of Satellite, Information and Communications
• /
• v.12 no.3
• /
• pp.80-85
• /
• 2017

In this paper, a mircrowave breakdown of X-band circular waveguide cavity filter, which occurred during ground test, was introduced, and electro-magnetic field simulation results to identify a root cause, and the analysis of possibility of its occurrence on orbit operation were presented. Filter modeling for simulation was conducted with a commercial tool (FEST3D), and electric fields inside the filter were monitored at the input of 1 W continuous wave. In our observation, strong electric field intensities were monitored on the tuning screws especially at the input of band-edge frequencies. The threshold power levels for the breakdown were also estimated and compared with the input power levels actually injected to the filter. From this estimation, we could figure out that the power exceeding the breakdown threshold was injected to the filter so that strong electric fields were generated and temperature increased high, and this became a root cause of the electrical short. Our further analysis showed that this kind of microwave breakdown is not likely to occur on orbit operation, and multipactor is expected not to occur at the input of band-edge frequencies. As a measure to prevent the microwave breakdown, we suggested to avoid the injection of band-edge frequencies and inject lower power levels to the filter.

• Proceedings of the KIEE Conference
• /
• 2000.11c
• /
• pp.500-502
• /
• 2000

고온 초전도 YBCO 박막을 Nd:YAG 레이저를 이용하여 MgO 기판에 증착시켰다. 박막을 마이크로스트립형 통신소자로 제작하기 위해 포토리스그래피 방법으로 습식 에칭을 시켰다. 제작된 박막에 접지면을 입히기 위해 스퍼터링 방식으로 Ti 충을 30 nm 증착하고, 열 증발기로 Ag를 $2{\mu}m$ 정도로 증착을 시켰다. 소자의 주파수 응답을 측정하기 위해 캐비티를 제작하여 측정하였다. 제작된 필터의 중심 주파수는 14 GHz이다. 박막을 냉각시켜며 그 중심 주파수를 측정하여 임계 온도를 측정할 수 있었다. 필터는 두 가지 디자인을 이용하였으며, 임계 온도에서의 중심주파수가 일정하게 이동함을 관찰할 수 있었다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.6
• /
• pp.483-488
• /
• 2020

In recent years, the demand for wireless devices incorporating several wireless communication systems into one has been increasing in order to provide services that meet the diverse needs of consumers. Wireless devices consisting of various wireless communication systems require many frequency fixed filters. A frequency tunable filter can replace a number of frequency fixed filters in the wireless devices. If a frequency tunable filter is used in wireless systems, the system can be configured more efficiently. In this paper, a 3-pole frequency tunable BPF(bandpass filter) operating in the frequency band of 800 ~ 2400MHz is designed. In order to widen the operating frequency band, a tuning screw is designed to have a step and a linear motor is used to facilitate the adjustment of the tuning screw. The implemented frequency tunable BPF operates in the designed frequency range and has the maximum insertion loss of 2.82dB in the channel band and the minimum attenuation of 18.7dB at ± 50MHz frequency offset from the center frequency of the band.