The scheme of the measurement workplace is shown in Figure 1. The complex channel impulse responses corresponding to the S41, S42, and S43, scattering parameters were measured utilizing a four-port vector network analyzer Agilent E5071C in the frequency domain for two different frequency bands, 3 to 11 GHz (entire UWB band with a bandwidth of B = 8 GHz) and 3.3168 to 4.752 GHz (first band group with a bandwidth of B = 1.58 GHz). The measurement was carried out in the Skoda Octavia 1.8 TSI car. In order to avoid a degradation of the measured phase accuracy due to movements of the RX antenna, phase-stable coaxial cables were used and included in the calibration process (full 4-port SOLT calibration using ECal module). Vertically polarized conical monopole antennas having H-plane omnidirectional radiation pattern were used for UWB measurement.

The RX antenna was placed at various locations inside the car compartment (on all seats and in the boot) and the TX antennas were placed on the left and right side of the dashboard, top corners of the windshield, and at the rear part of the ceiling. The channel measurements were carried out for both LOS and NLOS scenarios. NLOS was caused by the backrest of the seats, the dashboard, and/or persons sitting inside the vehicle. There were altogether 90 possible TX-RX combinations. For details of antenna placement please refer to [1].

Examples of measured scenarios:

• Position № 5 of Rx antenna: Download
• Position № 14 of Rx antenna: Download
• Position № 20 of Rx antenna: Download

VNA specifications for UWB measurement:

• Start frequency 3 GHz
• Stop frequency 11 GHz
• Bandwidth 8 GHz
• Frequency step size 10 MHz
• 801 points
• IF bandwidth 100 Hz
• Dynamic range > 90 dB
• Output power 5 dBm

Equipment of measuring workplace:

• Vector Network Analyzer Agilent E5071C
• Phase-stable coaxial cables SUCOFLEX 104P
• Conical monopole antennas
• JOBY GorillaPod
• Vacuum glass holders
• SMA female to SMA male 90-deg bend adapters
• SMA female to SMA female straight adapters