• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.814-820
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• 2015

In this paper, A high selective dual-band bandpass filter was proposed using a dual-mode ring resonator with two short-circuited stubs. For dual-mode resonance, the ring resonator is directly connected with non-orthogonal feed-lines via coupling capacitors. Two short-circuited stubs which are unequal lengths are simultaneously placed at two corners along the two symmetry plane of the ring resonator in order to obtain dual-band responses. Because the feeding angle perturbated ring resonator of the proposed dual-band bandpass filter has the symmetrical structure, Even/Odd mode analysis can be well applied to extract the scattering parameters and transmission zero frequencies. The proposed dual-band bandpass filter was designed and fabricated for WLAN(Wireless Local Area Network) application of IEEE 802.11n standard. The measured results showed a good agreement with the simulation results, and it should be well applied not only for WLAN applications but also for any other communication systems.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.144-151
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• 2006

A rectangular loop antenna for S-band radar is proposed. The proposed loop antenna is the modified type of folded monopole antenna. The feeding line is coplanar stripline with $180^{\circ}$ phase difference for operating in odd mode. The proposed antenna showed return loss of -15.57dB at the center frequency and bandwidth of about 790MHz (> 25%) under the condition of VSWR < 2. The gains of single, 1x2, and 1x4 array loop antennas are 4.3, 7.0, and 10.2dBi, respectively.