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K-Band Substrate-Integrated Waveguide Resonator Filter With Suppressed Higher-Order Mode
Boyoung Lee,Tae-Hak Lee,Kangho Lee,Man-Seok Uhm,Juseop Lee THE INSTITUTE OF ELECTRICAL ENGINEERS 2015 IEEE Microwave and Wireless Components Letters Vol. No.
<P>In this letter, we present a design method for K-band substrate-integrated waveguide (SIW) resonator filters utilizing TM<SUB>02</SUB> mode. More importantly, a methodology for suppressing an unwanted higher-order mode ( TM<SUB>11</SUB>) close to the passband is demonstrated. It is shown that suppressing the unwanted mode give rise to the improved stopband performance. In addition, the resonator used in this filter design has capability of adjusting the resonant frequency, and this allows for compensating the fabrication error. Verification of the presented design method has been carried out by fabricating and measuring the filter.</P>
Bandwidth Tuning of Resonator Filter Using Reduced Number of Tunable Coupling Structures
Lee, Boyoung,Nam, Seunggoo,Lee, Juseop Professional Technical Group on Microwace Theory a 2019 IEEE transactions on microwave theory and techniqu Vol.67 No.4
<P>This paper presents a new bandwidth tuning theory for Butterworth-response resonator filters. The presented theory shows that the bandwidth of odd-order Butterworth filters can be varied by adjusting only two interresonator coupling structures while maintaining a perfect impedance matching at the center frequency. In other words, this paper presents an analytic approach to reduce the number of tunable coupling structures when designing a bandwidth-tunable resonator filter. Theories for third- and fifth-order direct-coupled filters are discussed in detail, and it is shown that only two interresonator coupling structures are required to be tunable. In addition, for verifying the new bandwidth tuning method, a fifth-order cylindrical cavity filter has been designed, fabricated, and measured. The fabricated filter has an 11:1 bandwidth tuning range.</P>
A dual-mode waveguide pseudo-elliptic filter with zero-shifting properties
Lee, Juseop,Uhm, Man Seok,Yom, In-Bok,Kim, Jeong Phill Wiley Subscription Services, Inc., A Wiley Company 2005 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.47 No.4
<P>This paper describes the design and realization of dual-mode waveguide filters with zero-shifting properties. The transmission zero can be shifted from one side of the passband to the other by simply changing the resonant frequencies of the resonators. Without changing the physical dimensions of the resonators and coupling irises, transmission zeros can be shifted by adjusting the tuning and coupling screws. The filters are realized and the measured results show good agreement with the simulated ones. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 357–359, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21169</P>
Juseop Lee,Yongseok Lim,Hyunseok Ahn,Jae-Du Yu,Seung-Ok Lim IEEE 2014 IEEE antennas and wireless propagation letters Vol.13 No.-
<P>This letter presents a new analytic design method for impedance-matched wireless power transfer (WPT) systems using an arbitrary number of coils. For deriving the impedance matching condition, we have used an equivalent circuit of the WPT system. It allows us to avoid solving voltage-current equations for the actual circuit. For verifying the proposed design method, an impedance-matched WPT system with one repeater coil has been designed and fabricated. This letter also shows that the distances between the coils can be varied maintaining the impedance-matching performance, and the distances can be determined analytically using the presented design method. Application of the presented design method can be found in designing WPT systems that require flexible coil positioning.</P>
Lee, Juseop,Kim, Byungguk,Lee, Kangho,Chappell, William J. Cambridge University Press 2015 International Journal of Microwave and Wireless Te Vol.7 No.6
<P>In this paper, we show a second-order (four-resonator) absorptive bandstop filter circuit topology which gives a larger bandwidth compared to a first-order topology. Due to the absorptive characteristic, it creates a large attenuation at the center frequency using low-Q resonators. Since low-Q resonators can be used in generating a large attenuation, small-size resonators can be employed in bandstop filter design. Analytic design equations are provided so that a higher-order absorptive bandstop filter can be designed analytically. It is also shown that the second-order filter topology exhibits a better frequency selectivity having a same bandwidth. The proposed filter topology has been applied to a design of a miniaturized low-temperature co-fired ceramic bandstop filter with low-Q resonators. The Q-factor of the lumped-element resonators has been chosen to be 5 for demonstration.</P>
Juseop Lee,Naglich, E. J.,Sigmarsson, H. H.,Peroulis, D.,Chappell, W. J. IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.3
<P>In this paper, we show a new bandstop filter circuit topology. Unlike conventional bandstop filter circuit topologies, the new circuit topology has inter-resonator coupling structures. The presence of these inter-resonator coupling structures enables convenient switching from a bandstop to a bandpass filter. Using the new bandstop filter topology, this paper demonstrates a design of a frequency-agile bandstop-to-bandpass switchable filter. The filter is composed of tunable substrate-integrated cavity resonators and can be switched to have either a bandstop or bandpass response. Switching is achieved by turning on and off switches placed within the filter structure. A prototype of the proposed design is fabricated and the concept is verified experimentally.</P>
Network Parameters of 6-Pole Dual-Mode Singly Terminated Elliptic Function Filter
Lee, Juseop,Uhm, Man-Seok,Yom, In-Bok,Lee, Seong-Pal 한국통신학회 2003 韓國通信學會論文誌 Vol.28 No.7A
An output multiplexer of manifold type is widely used in a recent satellite transponder for its mass and volume reduction. For correct operation, the filters of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly-terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling coefficients are obtained easily without complicated matrix algebra such as orthogonal projection and similarity transformation. Two different-structure filters are taken into consideration and the network parameters of each filter have been extracted from the same transfer function. It is shown that the responses of two filters are same to each other since their network parameters are obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.
Synthesis of a self-equalized dual-passband filter
Lee, Juseop,Uhm, Man Seok,Park, Jong Heung IEEE 2005 IEEE microwave and wireless components letters Vol.15 No.4
This letter describes synthesis method for a self-equalized dual-passband filter. Compared to a conventional dual-passband filter, the self-equalized dual-passband filter can reduce bit-error rate (BER) in digital data communications and does not need an external equalizer for group delay equalization. To validate the synthesis method described in this letter, a 10-pole dual-passband filter which has two self-equalized five-pole elliptic-response passbands is synthesized.
Frequency-Tunable Low- $Q$ Lumped-Element Resonator Bandstop Filter With High Attenuation
Lee, Tae-Hak,Kim, Byungguk,Lee, Kangho,Chappell, William J.,Lee, Juseop Professional Technical Group on Microwace Theory a 2016 IEEE Transactions on Microwave Theory and Techniqu Vol. No.
<P>This paper presents a new lumped-element absorptive bandstop filter topology. It exhibits infinite attenuation at the center frequency and no reflection regardless of the quality factor (Q-factor) of the resonators. The new topology exhibits the absorptive characteristic with extremely low-Q resonators, whereas an absorptive bandstop filter topology in the literature cannot be used for such resonators. This superiority of the new filter topology is verified by comparing it with the topology in the literature. The filter designed using the new topology can change its center frequency by tuning only the capacitor values of the resonators. A 1.6:1 frequency tuning range maintaining the absorptive characteristic has been obtained by measurement.</P>
$K$ -Band Substrate-Integrated Waveguide Filter Using TM21 Mode With Enhanced Stopband Attenuation
Lee, Boyoung,Nam, Seunggoo,Koh, Beyoungyoun,Lee, Juseop THE INSTITUTE OF ELECTRICAL ENGINEERS 2017 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS Vol.27 No.8
<P>In this letter, we present a method for enhancing the stopband attenuation performance of a K-band TM21 mode filter using substrate-integrated waveguide resonators. To improve the stopband response, we suppress and move spurious resonant peaks and produce transmission zeros. The step-by-step procedure of the proposed three-step method is shown in detail. The measurements show that when using the presented method, the filters exhibit better stopband performances than those in which the presented steps are not followed.</P>