In this paper, a novel configuration of circular ultra-wideband (UWB) antenna with band rejection characteristic is presented. In order to obtain this characteristic, the spiral loop resonators resonating at the rejection frequency are located in both sides of the circular radiating patch. This novel structure provides the band-notched characteristic without the degradation of the UWB antenna performance itself. Furthermore, the notched band can be easily tuned by adjustment of resonator dimension because the size of the spiral loop resonators controls the corresponding resonance frequency. This prototype antenna has been fabricated on a substrate, Rogers 4003, with the thickness of 0.8 mm and relative permittivity of 3.38. The fabricated UWB antenna covers the frequency band from 3.1 to 11.23 GHz (S 11 ≤ −10 dB), and the band rejection characteristic appears near at 5.8 GHz band to which the wireless LAN service is assigned. And the far-field radiation patterns of the proposed antenna show omnidirectional and stable over the whole frequency band, which prospects the deployment in the UWB system. The measured results agree well with the simulation by the Microwave Studio of CST. This novel technique utilizing the spiral loop resonators might be useful to the planar antennas requiring the band rejection characteristics.
A triple-band flexible loop antenna is proposed for WLAN/WiMAX applications in this paper. The proposed antenna is formed by the third-order Hilbert-curve and bending type structure which provides flexible characteristics. Even though the radius of the curvature for bending antennas is changed, a triple-band feature still remains in the proposed antenna. Moreover, the antenna exhibits the characteristics of omnidirectional radiation pattern and circular polarization. To verify the receiving performance of antenna, a simulation on the antenna factor was conducted by an EM simulator. Based on these results, the suggested antenna makes a noteworthy performance over typical loop antennas.
Abstract-A numerical method is presented for determining the static charge distribution and capacitance of a round disk capacitor. Based on equivalent surface charge distributions, an integral equation subject to the boundary conditions is transformed into an algebraic equation by using the method of moments. In the proposed scheme to eliminate the discretizing errors often encountered in other techniques, annular patch subdomains are introduced, not only to improve the accuracy of solutions, but also to reduce the matrix size of the resultant equation. By solving the transformed algebraic equation, the charges per unit area on the interfaces are numerically determined. With use of the free charge on plates obtained by using annular patches, the capacitance is more accurately calculated. The equipotential lines around a round disk capacitor are also calculated.In order to show the usefulness of this method, the employed scheme is applied to a single circular disk with an exact solution, and to the dielectric filled capacitor partially covered by plates. Those results are examined and discussions are also made to support the validity of the presented scheme.
This paper provides an analytical derivation of the probability density function of signal-to-interference-plus-noise ratio in the scenario where mobile stations interfere with each other. This analysis considers cochannel interference and adjacent channel interference. This could also remove the need for Monte Carlo simulations when evaluating the interference effect between mobile stations. Numerical verification shows that the analytical result agrees well with a Monte Carlo simulation. Also, we applied analytical methods for evaluating the interference effect between mobile stations using adjacent frequency bands. The analytical derivation of the probability density function can be used to provide the technical criteria for sharing a frequency band.
Radio interference has been occurring in mobile communication services on the southern seashore in Korea. Monitoring the radio interference signal revealed that the main reason for the radio interference was a radio ducting signal coming from the seaside of Japan. In this paper, we have analyzed the effect of interference on WiMAX service using a 2.5 GHz frequency band between Korea and Japan. We focus on the interference scenario from base station to base station and we use the Minimum Coupling Loss (MCL) method for interference analysis and the Advanced Propagation Model (APM) for calculating the propagation loss in ducts. The propagation model is also compared with experimental measurement data. We confirm that the interfering signal strength depends on the antenna height and this result can be applied to deployment planning for each system with an interference impact acceptable to both parties.
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