# Null Steering of Circular Array Using Array Factor for GPS Anti-Jam

• Kwon, Taek-Sun (School of Electronic and Electrical Engineering, Hongik University) ;
• Lee, Jae-Gon (Metamaterial Electronic Device Research Center, Hongik University) ;
• Lee, Jeong-Hae (School of Electronic and Electrical Engineering, Hongik University)
• Accepted : 2018.06.19
• Published : 2018.10.31
• 35 6

#### Abstract

In this letter, the null steering of a circular array is presented using a modified array factor (AF) for a global positioning system (GPS) anti-jam. The seven radiating elements were designed using a mu-zero resonance (MZR) circularly polarized (CP) antenna arranged toward the center. Since the radiating elements, which are arranged toward the center, have a CP characteristic, the AF of the seven radiating elements has to be modified considering the rotation angle of the nth radiating element. The phases of input ports can be calculated to implement a nulling of radiation patterns where the modified AF is zero. To verify the modified AF for null steering in the desired direction, two cases of power dividers operating in $L_2$ band (1.2276 GHz) were fabricated to achieve pattern nulling at a certain angle. The modified AF can be confirmed by a comparing the simulated and measured radiation patterns.

#### Keywords

Anti-Jam;Array;Circular Array;Null Steering

#### Acknowledgement

Supported by : National Research Foundation of Korea (NRF)

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