Design of a Phased Array in Triangular Grid With an Efficient Matching Network and Reduced Mutual Coupling for Wide-Angle Scanning

In this paper, a wide-scan angle planar patch phased array is proposed. The proposed array is composed of wideband probe-fed microstrip patches placed 0.087 lambda(h) (lambda(h) is the wavelength of highest frequency) above individual ground planes and interlaced with parasitic decoupling walls. In order to cancel the feed probe inductance, the array elements comprise additional degrees of freedom to introduce controllable capacitance. Concurrently, individual ground planes and parasitic decoupling walls are proposed as an effective structure to considerably increase the E-plane scanning angle of the phased array by reducing the magnitude of near-field mutual coupling. A 544-element phased array prototype of the proposed element was designed, manufactured, and validated experimentally. The experimental results agree well with the numerical simulation ones and indicate effectiveness of the proposed design for mutual coupling reduction and wide-angle scanning. Because of the modifications, the measured mutual coupling between adjacent elements is reduced to lower than -32 dB at the center frequency. The proposed phased array has almost a constant active input impedance (active VSWR less than 2 over 20% bandwidth) up to scan angle of 65 degrees in E-plane and 60 degrees in H-plane, with a realized gain reduction of about 3.5 dB.