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This article presents a 3 × 2 element U‐slot patch antenna array with modified feed for airborne very high frequency applications. The antenna array is designed to upgrade the Multichannel Coherent Radar Depth Sounder/Imager on board the National Aeronautics and Space Administration DC‐8 aircraft. The antenna array is placed in an aerodynamic fairing structure designed for airborne operation. The major objective is to design an antenna array with a wider impedance bandwidth compared to the existing array. Impedance bandwidth improvement is achieved in two steps. First step is by increasing the bandwidth of antenna element itself and the second step is by utilizing the mutual coupling between the elements of the array. To avoid the problem associated with a rigid probe feed, a modified flexible feed is designed, which can withstand the atmospheric and aerodynamic forces at high altitudes. A matching network is used at each antenna element in this array to further improve the impedance matching. The final antenna array with fairing structure achieved a fractional bandwidth of the 62.5% at center frequency of 243.75 MHz. [ABSTRACT FROM AUTHOR]

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 λ × 0.21 λ × 0.07 λ where λ 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° to 50°. To analyse the performance of the finite array with mutual coupling, a prototype of 4 × 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. [ABSTRACT FROM AUTHOR]