• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.6
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• pp.13-20
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• 1999

An actual inverter, generally, has frequency dependent property. In this paper, the property is considered as the dependencies of an inverter value (real value) it self and its immittance(imaginary part). And a method is given to obtain the equivalent circuit that has indeal inverter and immittance elements from actual inverters. Using this method, BPF's can be designed more exactly than standard design method without optimizing methods.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.12
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• pp.1-7
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• 2007

This paper proposes the design method based on the composite right/left-handed (CRLH) structure to miniaturize and enhance the rejection performance in the stopband. For realization, we used the 0-th order resonance point of the unbalanced case of the CRLH and the simple theory of Inverter. The proposed technique is validated by the performance predictions and experiments, and it is found out that the suggested method enables the sire reduction of over 65 % from the conventional filters such as the parallel coupled type.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.380-388
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• 2005

This paper presents analysis results of the effects of RF filter characteristics on the system performance of impulse radio. The impulse radio system transmits modulated pulses having very short time duration and information can be extracted in receiver side based on cross-correlation between received and transmitted pulses. Accordingly, the pulse distortion due to in-band group delay variation can cause serious system performance degradation. In general, RF bandpass filters inevitably cause group delay difference to the signal passing through the filter which is proportional to its skirt characteristic due to its resonance phenomenon. For time as well as frequency domain analysis, small signal scattering parameter $S_{21}$ and its Fourier transform are used to characterize output pulse waveform under the condition that the input and output ports are matched. The output pulse waveform of the filter is predicted based on convolution integral between input pulse and filter transfer function, and resulting BER performances in the BPM and PPM based impulse radio system are calculated.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.94-100
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• 2017

In this paper, we suggest a design method of a metamaterial-based low-profile antenna working at 425 MHz for LEO/Cube satellites. Satellites play an important role in linking th remote nodes in a wireless communication network and covering wide areas of the globe. Especially, an increasing number of universities or individuals aspire having their own satellites and build low-budget structures such as cube satellites in LEO and the ways to reduce the sizes of their satellites. Since the antenna occupies a major portion of the satellite surface, the antenna should be miniaturized for lighter weight. The proposed metamaterial low-profile antenna, unlike the conventional patch antenna, produces such a zeroth-order resonance to create an omnidirectional radiation pattern. Also, it is connected to a UHF waveguide bandpass filter as the feeding system to examine the possible change in the situation that the antenna is combined with the system. The performances of the monopole and proposed metamaterial antennas are compared to one another.