A Parametric Study on the Self-Calibration Method of Systematic Errors for Onboard Digital Beam Forming Array Fed Reflector Antenna Using Gating Process

Abstract

The NICT is currently researching and developing an array-fed reflector antenna that flexibly changes the coverage area using a DBF and improves the frequency utilization efficiency using a DC for next-generation communication satellites in the Ka-band. The systematic error calibration of an array feed is very important because the influence of phase errors appears prominently in the characteristics of the antennas. We propose a self-calibration system for an array feed using a pickup antenna and gating process to realize a more accurate systematic error calibration for array-fed reflector antennas. The calibration values for the array feed are obtained from the coupling characteristics using a pickup antenna from which the noise is removed by a gating process. This paper shows the proposed method, procedure, and calibration results of the radiation pattern in an anechoic chamber. In order to determine the measurement parameters of the proposed method by parametric study, only the characteristics of the array feed were measured and evaluated. The calibration values, with gating a width of 0.01 μs, were almost the same compared with reference values. The calibrated radiation pattern using the proposed method was compared with a simulated radiation pattern, and the deviation in the H- and V-planes within a ± 6-degree range was about ±1.0 and ±0.6 dB, respectively. This paper shows that the proposed self-calibration using a pickup antenna and gating process is effective for a DBF array feed.