approach to ultra-wideband channel calibration using a vector network analyser," Australian Journal of Electrical and Electronics Engineering, vol. 11, (4) pp. 347-356, 2014. An approach to ultra-wideband channel calibration using a vector network analyser AbstractIn this paper, two calibration methods are investigated to determine the most suitable approach for ultrawideband (UWB) communication channel measurements. The fi rst method is the through, open, short and match (TOSM) calibration technique. The second method is through, refl ection and load calibration technique. Presented experiment results show that the through, refl ection and load calibration process is more precise for calibration of coaxial cables and the UWB channel as clearly seen by increased magnitudes of the channel transfer function. It is also shown that the proposed through, refl ection and load technique leads to an improved larger measured root-mean-square value and that the measured magnitude transfer function of the wireless channel is increased by an absolute value of approximately 5 dB after calibration compared with results achieved when TOSM technique is used. In the paper, it is also shown that the time delay associated with test equipment of the UWB channel measurement can be equally well removed by using either the through, refl ection and load or TOSM calibration techniques. KeywordsVector network analyser, calibration kit, cables, indoor ultra-wideband channels Presented experiment results show that the TRL calibration process is more precise for calibration of coaxial cables and the UWB channel as clearly seen by increased magnitudes of the channel transfer function. It is also shown that the proposed TRL technique leads to an improved larger measured RMS value and that the measured magnitude transfer function of the wireless channel is increased by an absolute value of approximately 5 dB after calibration compared with results achieved when TOSM technique is used. In the paper, it is also shown that the time delay associated with test equipment of the UWB channel measurement can be equally well removed by using either the TRL or TOSM calibration techniques.

In this paper, we analyze the measurement of ultra wideband (UWB) noise channels in different indoor environments. All measurements are done using a vector network analyzer (VNA) which allows us to measure the noise channel transfer functions. We find that the noise power of the system is decreased by increasing the intermediate frequency (IF) bandwidth which leads to an increase in time taken to perform measurements of the channels. Also, we measure the environmental noise power and find that it is slightly affected by fluorescent light sources inside the measurement environments. In addition, we find that the environmental noise is decreased when enclosed in a Faraday cage (steel shed), within an intense multipath measurement environment. As secondary application, we show how a frequency detection device can be used to readjust a maladjusted frequency selection on a remote controller for a garage door, in presence of environmental noise power.

In this study we propose using Ultra Wideband Channel measurements to detect the presence of different substances between the antennas. This technique takes advantage of the large number of frequencies which an Ultra Wideband signal occupies. We propose two methods to detect differences in channel magnitude frequency responses when in the presence of different substances between the transmitting and receiving UWB antennas. We then take preliminary measurements and fit a curve of best fit to the processed data. The preliminary results indicate that this technique may be able to be used in conjunction with data mining techniques to detect the presence of different substances between the antennas. This potentially provides a non-destructive technique to measure different substances in the wireless medium between the two UWB antennas.

This paper reports an investigation into the effect of carbon dioxide (CO2) gas on various ultra wideband channel coefficients. Measurements were conducted using apparatus consisting of a rubberized tube (6 mm diameter) connected to a source of CO2 or nitrogen (N2). For support, the rubberized tube was wrapped twice around a PVC pipe (160 mm diameter). The rubberized tube was flushed with 100% CO2 several times before being sealed in the tube at atmospheric pressure. In between measurement trials, removal of CO2 was achieved by flushing with pure nitrogen. A Vector Network Analyzer (VNA) using two identical directional antennas, with the wrapped section of tubing placed in‐between, measured the channel coefficients over ultra wideband frequency spans of (0.3–8) GHz and (1–2) GHz. Significant magnitude differences between the baseline condition and that of CO2 were observed. We found the same signature of difference curves over the same frequency spans for different measurements. Difference in shape in the frequency band of (1–2) GHz is the same as that of the measured difference over 1–2 GHz in entire frequency band of 300 MHz to 8 GHz for the measured channel coefficients. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1543–1546, 2016

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