This letter describes experiments conducted to measure the interference effects of two kinds of UWB sources, which are OFDM UWB source and pulse radio UWB source, to broadcasting relay system and SDMB system. The received power degradation of a broadcasting system is presented. experimental results show that UWB system can coexist 35 m distance as close as to in-band broadcasting network and can also coexist 1.8 m as close as with the SDMB terminal without causing any dangerous interference.

This paper presents the basic characteristics of a forced resonant type EMI dipole antenna for frequencies below 80 MHz in which two reactance elements are used for the impedance matching at the feed point. The input impedance of the short dipole less than half-wavelength is controlled by the properly determined loading position and the value of loading reactance. The integral equation for unknown current distribution is solved by Galerkin's method of moments with piecewise sinusoidal functions. The numerical results show that the small-sized EMI dipole antenna with lower antenna factors for frequencies below 80 MHz can be realized by the reactance loading. In case the proposed center driven small-sized EMI dipole antenna with 0.3λ length is loaded c=0.133λ from the center, the input impedance is matched at feed line with 50 Ω, and hence the antenna has lower factors in the frequency range of 30 to 80 MHz. Also the normalized site attenuation characteristics are presented for the forced resonant type EMI dipole antenna.