Scanning Angle Extension of a Millimeter Wave Antenna Array using Electromagnetic Band Gap Ground

A compact phased array with extended beam steering characteristic for the millimeter-wave band of the fifth generation (5G) applications is presented in this communication. An E-shaped patch antenna placed on an electromagnetic band gap ground (EBGG) with operating bandwidth of 24.2-27.5 GHz, is used as the basic building block of the eight-element linear array. The array utilizes both the in-phase reflection characteristic for broad element radiation pattern and the band gap characteristic for mutual coupling reduction for limited inter-element spacing of the proposed array. The existence of the EBGG enables a compact array with the inter-element spacing of around 0.4 wavelengths at the center frequency, yet the isolation between each element is still above 17 dB within the whole band of interest, which also help to increase the array directivity at large scanning angles. The scanning angle of the array with the EBG structure ranges from -75° to 75° at 26 GHz within 3 dB scanning loss. The proposed EBGG extends the antenna array’s spatial coverage and enables a compact size of the array, which is very attractive for 5G millimeter wave application.