RX Ant. (26.4 GHz) (5.2 GHz) (fix) Ground reflected path (moving) TX Ant. TX Ant. (26.4 GHz) (5.2 GHz) Figure 11.1 Measurement site and conditions. 11.2 Propagation Measurements Above 6 GHz Figure 11.2 Path loss in open space. 5.2GHz Free space loss 26.4GHz RX moving distance, D (m) Incident shadow boundary Tx = hrx=1.5 m NLOS area LOS area Diffraction wedge TX Antenna RX Antenna RX moving routes: 40 m 3.3 m Building Figure 11.3 Measurement site and conditions. 11.2.1.2 Building Corner Diffraction Loss Measurements were carried out for the building facing the parking space. Figure 11.3 shows the measurement site and conditions. In the measurement site, there are few buildings that reflect waves strongly. A CW is transmitted from a Tx antenna, and the received power level is recorded. The Tx and Rx antenna heights are set to 1.5 m. The antennas used for the Tx and Rx are sleeve antennas. The measured frequencies are 5.2 and 26.4 GHz. In this case, the difference in diffraction loss between the frequencies is theoretically 21.2 dB (=301og(26.4/5.2)); note that the component of the free space path loss is included [27]. Figure 11.4 shows the measurement results. When Rx moves to the on-line-of-sight - (NLOS) area, the path loss for 26.4 GHz increases more steeply than that for 5.4 GHz. This trend is consistent with theory. However, the average value of the difference between frequencies in the NLOS area is approximately 16 dB, which is less than above-mentioned theoretical value. It is thought that there are other propagation paths. 11.2.1.3 Building Penetration Loss Measurements were carried out in a long corridor of the building facing the parking space. Figure 11.5 shows measurement site and conditions. In the measurement site, there are few buildings that reflect waves strongly. A CW is transmitted from a Tx antenna, and the received power level is recorded on the 3rd, 4th, 5th, 6th, and 7th 11 Measurements C1 C2 C3 Incident shadow boundary 5.2 GHz 26.4 GHz Figure 11.4 Path loss VS. moving distance. distance 1.5