Measurement of Low-Gain Antennas in Non-Anechoic Test Sites through Wideband Channel Characterization and Echo Cancellation [Measurements Corner]

Sparse deconvolution based on regularisation for echo correction in antenna measurement

“…Measurements in the semi-anechoic scenarios used in [8] (Fig. 3) have been performed in order to verify the accuracy of the proposed method.…”

“…Some other limitations are related to the availability of enough samples of the frequency response of the system. However, it is clear that the proposed method may be applied, at least, in any case where the iDFT method [8] is valid, provided that the proposed method performs additional processing on the available measured data but does not modify the acquisition procedure.…”

“…The traditional approach for the iDFT method [8] requires a measurement bandwidth of about 2/dt, where dt is the time delay between the direct ray and the first echo. In the case of the CG model, the required bandwidth has been found to be about 0.5/dt, provided that the parameters of the model have been optimally set up, or about 1/dt if some reasonable error is assumed in the parameters.…”

“…All these methods allow the accuracy of antenna measurements to be improved also in non-ideal conditions. Some of the authors of this contribution have applied a technique based on the inverse Discrete Fourier Transform (iDFT) to retrieve the real radiation pattern of an antenna measured in a non-ideal environment with interesting results [8]. Considering individually each direction and measuring using a certain bandwidth, it is possible to identify the frequency response of the measurement system consisting of the chamber, the probe and the antenna.…”

“…Making use of (10), finding the maximum of the first term in (9) means minimising the exponent in (10). Then, (8) can be reformulated [9 -11] as the minimisation of a cost function J(h) defined as…”