Fast Direction Finding System with Few Antenna Elements for IoT Applications

Abstract

Σ

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Δ

[dB],

[dB]) along with the phase comparison(∠Σ-∠Δ [º], ∠Δ-∠Σ [º]) of Σ-Δ ratio and Δ-Σ ratio, it may be able to resolve ambiguity issue and also improve resolution. Extra analysis was done since the proposed system can be influenced by the mutual coupling between/among antenna elements and the multipaths by surrounded environment. Furthermore, a environement which multipath can influence less on the proposed system is suggested.

This thesis propose various types of fast direction finding systems which can find the direction of a sensor with fast speed and wide scan range by utilizing only small number of antenna elements. The proposed system finds and detects direction by generating two different beams simultaneously, and then compares the value of the incident signal received by these two beams in ratio named beam comparison ratio. The proposed feeding network generates Σ-beam and Δ-beam at each two output port of the feeding network. It can also weight each antenna element by phase shifters to shift direction of the observation angle and therefore widens scan angle range. The comparator gets the signals received by Σ-beam and Δ-beam as its inputs and compares the value of the two in ratio. This study suggests to utilize not only the Σ/Δ value named Σ-Δ ratio but also the Δ/Σ value named Δ-Σ ratio at the same time to scan the direction of a sensor. Utilizing both method at once enables to reduce the number of phase shift adjustments in half, allowing fast scan and downsizing the power consumption. By using both amplitude comparison(