Tae-Ui Hong

Design of a 5.8 GHz Narrow Band-pass Filter with Second Harmonic Suppression Using the Open Stubs

In this paper, integration of bandstop filter with the flexible narrow bandwidth of bandpass filter with lambdag/2 open stubs by microstrip line on duroid substrate is presented. This kind of filter shows flexible bandwidth with variation of the position of the open stubs using the external quality factor, Qe without changing the impedance value at microwave range. On the other hand, by replacing the series quarter-wavelength connecting lines with the equivalent T-shaped line, one could have compact stub bandpass filter with second harmonic suppression. This filter shows the insertion loss of 1.2 dB and the return loss of 21.9 dB at the center frequency of 5.8 GHz.

Compact Broad Band-pass Filter of Parallel Coupled Structure with SIR

In this paper, the reduced size of broad bandpass filter with parallel coupled line structure is presented. This proposed filter can control bandwidth of narrow to broadband by adjusting the coupling coefficient. The conventional filter is operated with a narrow band. If a higher bandwidth is desired than the conventional narrow bandwidth, it is hard to realize due to the coupling coefficient between feeding line and resonator. In this paper, to overcome this limitation, a proposed bandpass filter is designed with reduced size due to SIR (Stepped Impedance Resonator), U-shaped open stub with hair-pin and vertical-type structure than conventional one, and it has characteristics of adjusting bandwidth freely as per quantity of coupling coefficient. The proposed bandpass filter that, experimental results of insertion and return losses are 0.42 dB and 24.5 dB with bandwidth of 60 % at the center frequency of 5.8 GHz, respectively.

Dual-Band Compact Broad Band-Pass Filter with Parallel Coupled Line

In this paper, the dual-band compact broad bandpass filter using parallel coupled line is proposed. The proposed filter has reduced size and can be controlled bandwidth. And it is also possible to operate in the dual-band purpose. Futhermore, the inserted bandstop fiilter with T-type configuration is also possible to operate in the same purpose. The dual-band bandpass filter has the first operating frequencies and its bandwidth which are 5.8 GHz and 60 % respectively and the second operating frequency and the bandwidth are 16.2 GHz and 60 % respectively. The insertion loss and the return loss of the first frequency has 0.4 dB and 17.4 dB and the insertion loss and the return loss of the second frequency has 0.62 dB and 19.8 dB, respectively.