New approach to suppress mutual coupling between longitudinal-slotted arrays based on SIW antenna loaded with metal-fences working on VHF/UHF frequency-bands: Study, investigation, and principle

In this work it is demonstrated that substrate integrated waveguide longitudinal slotted array antenna (SIWLSAA) which is loaded with metal fences exhibits highisolation across VHF/UHF bands. A reference SIWLSAA used for comparison purpose comprises of 3×6 slotted arrays constructed on the top and bottom sides of the FR-4 lossy substrate has maximum isolation of -63 dB between its radiation slots. Improvement in isolation is demonstrated using a simple new technique based on inserting a metal fence between each row of slot arrays. The resulting isolation is shown to be is better than -83 dB across 200 MHz to 1.0 GHz with gain greater than 1.5 dBi, and side-lobe level less than - 40 dB. The proposed SIWLSAA is compact and has dimensions of 40×10×5 mm3 (0.026λ 0 ×0.006λ 0 ×0.002λ 0 ) where λo is 200 MHz. The proposed structure should find application in multiple-input multiple-output (MIMO) and radar systems