Effect of random errors in cylindrical near field measurements

IEEE Antennas Propag. Mag.

2011

A method to reduce the noise power in far-field pattern without modifying the desired signal is proposed. Therefore, an important signal-to-noise ratio improvement may be achieved. The method is used when the antenna measurement is performed in planar nearfield, where the recorded data are assumed to be corrupted with white Gaussian and space-stationary noise, because of the receiver additive noise. Back-propagating the measured field from the scan plane to the antenna under test (AUT) plane, the noise remains white Gaussian and space-stationary, whereas the desired field is theoretically concentrated in the aperture antenna. Thanks to this fact, a spatial filtering may be applied, cancelling the field which is located out of the AUT dimensions and which is only composed by noise. Next, a planar field to far-field transformation is carried out, achieving a great improvement compared to the pattern obtained directly from the measurement. To verify the effectiveness of the method, two examples will be presented using both simulated and measured near-field data.

Section: Introductionmentioning

confidence: 89%

Section: Simulation Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Novel Method to Improve the Signal-To-Noise Ratio in Far-Field Results Obtained from Planar Near-Field Measurements

Cano-Fácila

Burgos²,

IEEE Antennas Propag. Mag.

2011

“…Both of them start with random errors in planar near-field (PNF) and obtain expressions that represent the signal-to-noise ratio in far-field as a function of the noise power in near-field. A similar study for cylindrical near-field (CNF) measurements was carried out in [9], [10].…”

Section: Introductionmentioning

confidence: 96%

Methods for Noise Reduction in Far-Field Patterns Obtained From Cylindrical Near-Field Antenna Measurements

Cano-Fácila

IEEE Trans. Antennas Propagat.

2012

Abstract-Two different methods to reduce the noise power in the far-field pattern of an antenna as measured in cylindrical nearfield (CNF) are proposed. Both methods are based on the same principle: the data recorded in the CNF measurement, assumed to be corrupted by white Gaussian and space-stationary noise, are transformed into a new domain where it is possible to filter out a portion of noise. Those filtered data are then used to calculate a far-field pattern with less noise power than that one obtained from the measured data without applying any filtering. Statistical analyses are carried out to deduce the expressions of the signal-tonoise ratio improvement achieved with each method. Although the idea of the two alternatives is the same, there are important differences between them. The first one applies a modal filtering, requires an oversampling and improves the far-field pattern in all directions. The second method employs a spatial filtering on the antenna plane, does not require oversampling and the far-field pattern is only improved in the forward hemisphere. Several examples are presented using both simulated and measured near-field data to verify the effectiveness of the methods.

Section: Introductionmentioning

confidence: 99%

Application of postprocessing techniques methods for noise reduction in cylindrical near field antenna measurements

Facila

2012 6th European Conference on Antennas and Propagation (EUCAP)

2012