Antenna near-field measurement method and device using interpolation algorithm

Abstract

The application discloses an antenna near-field measurement method using an interpolation algorithm. Step S10: Collect and record the electric field amplitude and phase information on the near-field scanning surface of the antenna to be tested; the near-field scanning surface is an arbitrary curved shape, and must satisfy the following three conditions at the same time. Step S20: Interpolating the electric field amplitude on the near-field scanning surface of the antenna to be tested by cubic spline interpolation. Step S30: Interpolating the phase of the electric field on the near-field scanning surface of the antenna to be tested by bilinear interpolation. Step S40: Based on the amplitude and phase values ​​of the near-field electric field of the antenna under test obtained by interpolation, calculate the far field electric field of the antenna under test according to the Huygens equivalent principle. Step S50: Calculate the far-field normalized pattern of the antenna under test based on the calculated far field electric field of the antenna under test. The near-field scanning surface in the above method is not limited to plane, cylinder and sphere, and can be changed into any curved surface according to the change of the actual measurement environment.

Description

technical field [0001] The present application relates to an antenna near field measurement method, in particular to an antenna near field measurement method using an interpolation algorithm. Background technique [0002] Antenna measurement methods mainly include direct method and indirect method. The direct method is the far-field measurement method, and the indirect method is the near-field measurement method. Antenna near-field measurement is generally carried out in a microwave anechoic chamber. The probe antenna is used to scan to obtain the data of the radiation field in the near-field area of ​​the antenna to be tested, and the far-field pattern of the antenna is calculated through near-far field transformation. [0003] According to different types of scanning surfaces, common antenna near-field measurements include planar, spherical, and cylindrical near-field measurements. With the increasing application of conformal antennas, it is difficult to form a regular sc...

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Problems solved by technology

This method still has some shortcomings

First, the near-field electric field components directly obtained in the measurement system are usually amplitude and phase values. This method requires a mathematical transformation to convert the amplitude and phase components into real and imaginary components, which increases the amount of additional calculations.

Second, this method only has a small interpolation error when the scanning surface (also called the sampling surface) is spherical. After changing the shape of the scanning surface, the interpolation result of the imaginary component of the electric field is not ideal, which affects the accuracy of subsequent calculations

Third, if the method is changed to interpolation of the amplitude and phase components of the near-field electric field, the curve obtained by bilinear interpolation is not a smooth curve because the amplitude value of the electric field is very gentle compared with the phase value. The interpolation results do not fit well with the theoretical results at locations where the values ​​change abruptly

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