Research into the Influence of Millimeter-Wave Antennas on Direction Finding Errors by Phase Method

Abstract

Introduction. Direction finding errors degrade the performance of any direction finding system. In the case of a phase direction finder, the cause of errors, among other things, is related to the non-identity of the receiving channels. Research into the influence of antennas on direction finding errors, as well as a search for ways to reduce these errors, appear to be relevant tasks in terms of improving the quality of direction finding systems.Aim. To study the influence of millimeter-wave antennas on the errors of the phase direction finder.Materials and methods. For a series of four millimeter-wave antennas, the following characteristics were obtained: spatial gain readings, phase diagram readings, and complex reflection coefficient values. Based on the characteristics obtained for several spatial directions, matrices of characteristics were formed. For each matrix, the L norm was found. Based on the differences between the obtained L norms, conclusions were drawn about the degree of difference between the antenna characteristic matrices. According to the degree of similarity between the characteristic matrices, the antennas were grouped in pairs. The L norms of the antenna matrices from one pair differed insignificantly compared to the differences between the L norms of the antenna matrices from the second pair. With each pair of antennas, the bearing and direction-finding errors were determined in the range of angles φ: −15…15° in increments of 1°. The values of direction-finding errors obtained for each pair of antennas were compared with each other.Results. The obtained values of direction-finding errors for two alternately used pairs of antennas differ in the entire considered range of angles. Moreover, a pair of antennas with a smaller difference L norm is characterized by a lower level of direction-finding errors. At most points in the angular range, the difference in DF errors for two pairs of antennas falls within the range of 0.05 to 0.1°. At the boundaries of the angular range, the direction-finding errors increase, with the largest difference of 0.5° being observed at an angle of ϕ = 15°.Conclusion. Differences in the characteristics of antennas installed in the same phase-metric base lead to an increase in direction finding errors. A method for quantifying the non-identity of antennas is proposed. The proposed method can be used to group antennas in phase-metric bases, which will reduce direction-finding errors by the phase method.

Keywords

• antennas
• wave matrix
• phase direction finder
• direction finding errors