Sang-Won Yun

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A novel bandpass filter using microstrip quarter-wavelength resonators is proposed. The proposed filter consists of the open stub inverter between quarter-wavelength resonators, which results in a compact design as well as low loss. The tapped open stub not only works as a K-inverter but also introduces an attenuation pole. The attenuation pole can be(More)
  • Byung-Wook Kim, Sang-Won Yun
  • IEEE Transactions on Microwave Theory and…
  • 2004
In this paper, a varactor-tuned combline bandpass filter using step-impedance microstrip lines is considered so that the absolute passband bandwidth can be maintained nearly constant within the tuning range. The difference between the odd- and even-mode characteristics of the coupled microstrip line makes it difficult to design a tunable bandpass filter(More)
In this paper, a size-reduced aperture-coupled tunable hairpin bandpass filter which has improved selectivity and has constant bandwidth is proposed. We used an aperture coupling between first and second stage of the filter to reduce the size of the filter. Varactors are loaded to open end of the quarter-wave resonators to tune the center frequency. The(More)
New design equations and a 3-dB microstrip coupler example for N-section tandem connected structure with wide bandwidth are presented. The proposed four-port S-parameters and equations are obtained from a port reduction method. The designed microstrip 3-dB coupler not only does not need high impedance lines, but also uses tight coupling gaps differently(More)
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