A Low-Profile Light-Weight Wideband Connected Parallel Slot Array for Wide-Angle Scanning

A novel wideband-connected parallel slot array for wide-angle scanning applications is proposed in this article. Different from conventional connected slot arrays, the proposed array consists of dual parallel slots, where the introduced parasitic slot acts as an additional series capacitor. The connected parallel slot array can realize low and moderate active input impedances and achieve wide bandwidth without using any complex balun. To improve the wide-angle impedance matching issue and avoid an increase in the array profile, a mixed periodic metallic strips layer with almost zero height and weight was adopted. The metallic strips layer can be regarded as a shunt capacitance between the array and free space. Additionally, equivalent circuit models were established to analyze the function of the introduced parasitic slot and metallic strips layer. The proposed connected parallel slot array achieves a concurrent bandwidth of approximately 69.2% (1.35-2.78 GHz), while covering a scanning area of ±60° in the E-, H-, and D-planes. The profile is only 0.088 λ
_L
, where λ
_L
is the wavelength of the lowest operation frequency in free space. Besides, low cross-polarization in principal planes, planar and simple structure, and light weight are also the merits of the proposed antenna array.