the measurements, a CW was transmitted from a Tx antenna, and the 11.2 Propagation Measurements Above 6 GHz Shadowing width Calculation with UTD 12 GHz 15 GHz Measurement 18 GHz Position of human body, y (cm) Frequency (GHz) Figure 11.10 Human body shadowing loss: (a) relationship between position of human body and shadowing loss, (b) frequency dependency. Window Pedestrian Figure 11.11 Measurement in meeting room. received level was measured. The measured frequencies are 0.81, 2.2, and 19.85 GHz. Tx and Rx antennas are sleeve antenna, and the antennas were fixed during the mea- surement. Moreover, the measurement was performed at the Tx antenna height, hTx, of 1.3, 1.8, and 2.5 m to clarify the antenna height characteristics. The height of Rx, hRx is 1.3 m in all measurements. The distance between the Tx and Rx antennas is 9 m, and the received levels were measured in 180 S when pedestrians walked randomly in the indoor environment. The measurement was performed when the pedestrian number, N, was 1, 3, and 5. Pedestrians walked only within the gray area between the Tx and Rx antennas in Figure 11.11. Figure 11.12 shows the distributions of the received levels for each pedestrian number in 0.81, 2.2, and 19.85 GHz, where hTx = hRx = 1.3 m. Here, the received levels are nor- malized to a 99% value in each result. The variation range of the received levels becomes large with an increase in the pedestrian number N. The distributions of the received levels at 0.81 and 2.2 GHz change smoothly; however, the gradients of the distributions at 19.85 GHz change significantly, and the received levels tend to drop when the cumu- lative distribution function (CDF) value is relatively small. It is considered that these 11 Measurements 0.81 GHz 2.2 GHz N = = 1 N = 0 Relative received level (dB) Relative received level (dB) 19.85 GHz N = 0 Relative received level (dB) Figure 11.12 Distribution of received levels VS. pedestrian number, N, where hTx =hrx=1.3m. phenomena occur due to the following reasons. In the cases of 0.81 and 