• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1150-1155
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• 2006

In this paper, the equivalent circuit of tapped-line that is applied in the band-pass filter is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and transmission line that has negative electrical length, and the position of tapped-line and the value of resonator's length can be obtained by the impedance of resonator and the inverter. The new design method using equivalent circuit leads to very good agreement compared with theoretical value. The hair-pin band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.1 dB and the return loss of 20 dB at the center frequency of 2 GHz.