Characterization of standing wave movement by in-line antennas

The interaction of incident radiowave fields with multiple-port antennas on a moving vehicle is investigated. The interest is for in-line antennas which trace identical paths through a standing wave field and receive similar, but not identical, (time-displaced) signals as the mobile moves through typical multipath environments. The investigation quantifies the similarity of the received signals using the average peak cross-correlation of the envelopes. This, as a function of the antenna spacing, offers a quantitative assessment of the effective movement of standing wave fields. However, when the antenna spacing is less than 0.5 wavelengths, the peak cross-correlation measure is strongly perturbed by the mutual coupling effects of terminated antennas. For the 851 MHz measurements reported, the speed range of 15 km/h to 50 km/h (12 to 40 wavelengths per second) did not consistently affect the results for antenna spacings of up to 1.44 m (4.1 wavelengths).<>