Compact UHF three-element sequential rotation array antenna for satcom applications

This paper proposes a miniaturized UHF antenna with three sequentially rotated elements operating at 433 MHz for Satcom applications. Like most of its former counterparts, the antenna consists of a main body with three radiation elements driven by a feeding network. To evaluate the matching characteristics of the main body, a united reflection coefficient for the three elements, taking into consideration the coupling between them, is derived. The main body is formed by three sequentially rotationally arranged bent planar inverted-F antenna elements, which helps dramatically reduce the size of the antenna. To drive the main body, a new compact feeding network based on spiral-shaped Wilkinson power divider is also developed, achieving three-way power splitting and 120° phase shifting. It has the merits of compact planar structure, equal power splitting, and high isolation between output ports. In this way, a sequential rotation array antenna with compact size (O 0.216\lambda -{0} ), low cost, easy fabrication, and good performance is realized. A prototype is fabricated and measured, and the results prove the good performance of the proposed design.