Low-Profile Wide-Scan Closely Spaced Antenna Array of Electrically Small Antennas

In this paper, a wideband, wide-scan, low-profile antenna array of electrically small monopole antennas is proposed. The array is designed for L-band applications. An electrically small antenna with an in-built feed and matching network is proposed as an unit element of the phased array. The size of the unit cell is 0.15 lambda x 0.21 lambda x 0.07 lambda where lambda is free space wavelength at 1 GHz. The array is designed taking into account strong mutual coupling between the elements. For the case of the infinite array, an impedance bandwidth of 45.7% is observed along with wide angle scanning of -50 degrees to 50 degrees. To analyse the performance of the finite array with mutual coupling, a prototype of 4 x 4 element finite array has been simulated and fabricated. For the finite array, more than 80% efficiency is observed throughout the band of interest. The prototype of the proposed array is fabricated and tested. A significant match is observed in measured and simulated results.