Printed quadrifilar square-helical antennas with folded arms for satellite applications

In this study, a new straightforward method for construction of the printed quadrifilar helical antennas is presented. Folded helices with square shapes are used as the arms of the proposed antenna for satellite applications. The proposed structure is consisting of four printed flat walls with similar patterns of arms on each wall. Patterns of the folded arms are printed on four flat substrates with removed ground layers and the antenna structure is obtained by connecting these substrates. Two versions of the proposed antennas are designed for operating at 435MHz with isolated and connected arms. Both antennas have minor responses at 145MHz; however the large antenna with connected arms has better results. In addition, the large antenna has wider bandwidth and higher gain at both operating frequencies. Furthermore, the proposed antenna can be used as a wideband antenna with 34% bandwidth.