Fast and efficient near-field to near-field and near-field to far-field transformation based on the spherical wave expansion

2015 ◽  
Author(s):  
B. Boesman ◽  
D. Pissoort ◽  
G. Gielen ◽  
G.A.E. Vandenbosch
Keyword(s):  
Near Field ◽  
Spherical Wave ◽  
Far Field ◽  
Wave Expansion ◽  
Field Transformation ◽  
Spherical Wave Expansion

scholarly journals Near-Field to Far-Field RCS Prediction on Arbitrary Scanning Surfaces Based on Spherical Wave Expansion

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7199
Author(s):  
Woobin Kim ◽  
Hyeong-Rae Im ◽  
Yeong-Hoon Noh ◽  
Ic-Pyo Hong ◽  
Hyun-Sung Tae ◽  
...  
Keyword(s):  
Near Field ◽  
Linear Equations ◽  
Spherical Wave ◽  
Scattered Wave ◽  
Far Field ◽  
Field Region ◽  
System Of Linear Equations ◽  
Wave Expansion ◽  
Field Transformation ◽  
Spherical Wave Expansion

Near-field to far-field transformation (NFFFT) is a frequently-used method in antenna and radar cross section (RCS) measurements for various applications. For weapon systems, most measurements are captured in the near-field area in an anechoic chamber, considering the security requirements for the design process and high spatial costs of far-field measurements. As the theoretical RCS value is the power ratio of the scattered wave to the incident wave in the far-field region, a scattered wave measured in the near-field region needs to be converted into field values in the far-field region. Therefore, this paper proposes a near-field to far-field transformation algorithm based on spherical wave expansion for application in near-field RCS measurement systems. If the distance and angular coordinates of each measurement point are known, the spherical wave functions in an orthogonal relationship can be calculated. If each weight is assumed to be unknown, a system of linear equations as numerous as the number of samples measured in the near electric field can be generated. In this system of linear equations, each weight value can be calculated using the iterative least squares QR-factorization method. Based on this theory, the validity of the proposed NFFFT is verified for several scatterer types, frequencies and measurement distances.

Near-Field Far-Field Transformation Utilizing 2-D Plane-Wave Expansion for Monostatic RCS Extrapolation

2016 ◽  
Vol 15 ◽  
pp. 1971-1974 ◽  
Author(s):  
Shuntaro Omi ◽  
Toru Uno ◽  
Takuji Arima ◽  
Takao Fujii ◽  
Yujiro Kushiyama
Keyword(s):  
Plane Wave ◽  
Near Field ◽  
Far Field ◽  
Plane Wave Expansion ◽  
Wave Expansion ◽  
Field Transformation

scholarly journals Probe-corrected near-field to far-field transformation using multiple spherical wave expansions

2020 ◽  
Vol 12 (6) ◽  
pp. 447-454
Author(s):  
Fernando Rodríguez Varela ◽  
Belén Galocha Iragüen ◽  
Manuel Sierra Castañer
Keyword(s):  
Near Field ◽  
Spherical Wave ◽  
Irregular Sampling ◽  
Field Pattern ◽  
Far Field ◽  
Transformation Technique ◽  
Sampling Schemes ◽  
Field Transformation ◽  
Simulated Field ◽  
Far Field Pattern

AbstractNear-field to far-field transformations constitute a powerful antenna characterization technique for near-field measurement scenarios. In this paper, a near-field to far-field transformation technique based on multiple spherical wave expansions (SWEs) is presented. Thanks to its iterative matrix inversion nature, the approach performs the transformation of fields measured on arbitrary surfaces. Also, irregular sampling schemes can be incorporated. The proposed algorithm is based on modeling the antenna fields with not one, but several SWEs distributed over its geometry. Due to the high number of SWEs, their truncation number can be arbitrarily reduced. Working with expansions of low order allows us to incorporate the probe correction in the transformation in a very simple way, accepting any type of probe and orientation. Only the probe far-field pattern is used, thus working with its full SWE is avoided. The algorithm is validated using simulated field data as well as measurements of real antennas.

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