Indoor antennas for WCDMA systems

In an interference limited mobile communication system such as the 3rd generation WCDMA, the dynamic range of the mobile station's transmitter is of high importance since in case the path loss to the base station (BS) antenna is low, a limited dynamic range will cause interference to other users. Another aspect of this problem is the minimum coupling loss (MCL) of an indoor antenna used for providing coverage for e.g. office environments. In these areas the user may occasionally be located very close to the antenna, thus underlining the importance of the MCL characteristics of the antennas employed. In order to study the MCL of each antenna in realistic conditions, a set of measurements were carried out with indoor antennas for UMTS. The antennas were placed in their natural environments, i.e. the antennas were either office ceiling- or wall-mounted. A test transmitter and a receiver operating at 1800 MHz, with a proper attenuation, was employed to radiate a signal with the antenna. The results showed that the lowest MCL values of roughly 30 dB were measured with wall-mounted directional antennas.