Building Entry Loss (BEL) Characteristics for Incident Angles and Measurement Locations from 3.5 to 24 GHz

Abstract

An effect of a building entry loss (BEL) on incident angles has been investigated in a traditional office building from 3.5 to 24 GHz band. The BEL was measured at three different positions in the window, the office center, and the corridor, moving a receiver (Rx) from 1 m away from the window (W) to the inside on the 6th (6F) and 9th (9F) floor of the building. As the Rx location moves from the window (W) to O and C inside of the building, the BEL increases and its slope for the azimuth angle decrease on the 6F, where the signal is directly incident. This tendency was not observed in 9F with an elevation angle of 12.8°. These results reveal that there is a breakpoint and propagation mechanism is different at each Rx location. For cumulative distribution function (CDF) of the BEL, as the frequency increases to 3.5, 6, and 10 GHz, the BEL increases. However, it decreases at 24 GHz at all Rx locations and all elevation angles because of frequency dependency of the input impedance of the air dielectric interface in the double layered-glass window. As the elevation angle increases from 0 to 12.8° in the window, the BEL increases from 4.2 to 11.7 dB at 50 percentile level of the CDF.