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RISS 인기검색어
- 검색키워드
- 저자 : Chappell William J. (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Co-Design of Highly Efficient Power Amplifier and High-<tex> $Q$</tex> Output Bandpass Filter
Kenle Chen,Juseop Lee,Chappell, William J.,Peroulis, Dimitrios IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.11
<P>This paper reports the first co-design configuration of a power amplifier (PA) in cascade with a high- Q bandpass filter. By matching the filter's input port directly to the transistor's drain node, the conventional output matching network (OMN) of a PA is entirely eliminated. This leads to smaller size/volume, minimized loss, and enhanced overall performance. To enable this co-design method, the matching-filter synthesis theory is proposed and investigated in detail in this paper. Based on this theory, a 3% bandwidth (centered at 3.03 GHz) two-pole filter, implemented using high- Q evanescent-mode cavity resonators, is designed as the PA OMN to provide optimized fundamental and harmonic impedances for a commercial 10-W GaN transistor. Simulation and measured results show that the co-designed PA-filter module yields a desired Chybeshev filter behavior while maintaining excellent PA performance in the passband with 72% efficiency, 10-W output power, >10-dB gain, and 60-dBm output third-order intercept point. This co-designed module experimentally presents a 8% higher overall efficiency compared to a control group developed using a conventional independent PA and filter, which further validates the effectiveness of this method.</P>
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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>
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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>
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RF CMOS Integrated On-Chip Tunable Absorptive Bandstop Filter Using Q-Tunable Resonators
Byungguk Kim,Jangjoon Lee,Juseop Lee,Byunghoo Jung,Chappell, William J. IEEE 2013 IEEE transactions on electron devices Vol.60 No.5
<P>A new approach for protecting sensitive receivers through large attenuation and its realization on-chip is presented for the first time. This paper demonstrates the use of absorptive bandstop filters that gives anomalously deep notches for a given quality factor. This approach is used in a fabricated design example to isolate a sensitive wideband LNA from interference in 45-nm SOI complementary metaloxide-semiconductor (CMOS). For reconfigurable RF front-ends, a frequency-agile design is newly developed with Q tunable resonators because an absorptive bandstop filter must balance both intrinsic Q of the resonators and the resonant frequency of the filter. Therefore, the design requires variable resistors, variable capacitors, and intimate coupling of inductors of disparate values. The layout of overlapping inductors on closely spaced metal layers is required for proper absorptive properties. The size of one filter presented in this paper is 310 by 340 μm, making it the smallest absorptive bandstop filter demonstrated so far. Despite using small-size, on-chip low-Q resonators in the bandstop filter design, an attenuation level from 31 to 63 dB and a frequency tuning range from 2.9 to 4.3 GHz are achieved with potential to suppress potential interference or an image frequency signal.</P>
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