All-Metal Low-Profile Dual-Polarized Phased Array With 3:1 Bandwidth

An all-metal low-profile dual-polarized phased array (DPPA) with 3:1 bandwidth is proposed. It consists of two sets of orthogonally arranged wideband single-polarized phased arrays (SPPAs). Each SPPA element employs a new height-reduced stepped flaring slot to obtain the required wideband radiation propriety. Compared with the Vivaldi-based phased array, it decreases the array profile while maintaining the characteristics of wideband response and easy computer numerical control (CNC) machining. An extra easy-to-fabricate square wall is loaded around the feeding part (coaxial probe) of each element to achieve wideband impedance matching. After the DPPA formation, the crosstalk of the E-field between the orthogonal polarizations at high frequencies is further suppressed by optimizing the size of the radiating part. This helps to improve the rapid gain drop during beam scanning. To demonstrate the feasibility of the concept, two prototypes covering 10-30 GHz are fabricated and tested. The radiating and feeding parts of all elements are combined and manufactured in reasonable layers, which avoids the difficulty of assembling individual elements, as encountered in Vivaldi phased arrays. The experimental results show that a beam scanning range of +/- 55 degrees with a gain drop of less than 4.7 dB is achieved in the target frequency range.