Grating-Lobe Reduction for Non-Uniform Linear Array Using High order mode

Eigenmode theory has been a subject of great interest in antenna engineering in recent years. High-order mode (HOM) theory is concerned with the propagation and behavior of electromagnetic waves above the fundamental mode in radiating sources, such as waveguides, optical fibers, and resonators. This theory is used to analyze the modal resonant behavior of objects with arbitrary geometric shapes, such as antennas and scatterers. In array antennas, grating lobes are unwanted patterns that occur when the spacing between antenna elements is large relative to the signal wavelength. These lobes can appear in undesirable directions, degrading the antenna's performance, including its directivity and gain. There are some methods for reducing grating lobes, such as reducing element spacing, using non-uniform or random spacing to disrupt periodicity, applying beamforming weights to suppress sidelobes, and considering wideband or multi-subarray techniques for additional control. One of the important methods for reducing grating is to create nulls in the radiating pattern. Therefore, using the characteristic mode method in forming the distribution of different currents in the higher-order mode is very effective in steering the radiation pattern. Using this method has reduced the Grating lobe level by -۵۰ dB.

کلیدواژه ها:

High-order mode ، grating lobes ، nulls in the radiating pattern ، Eigenmode