A Miniaturized Circular-Polarization Reconfigurable UHF Antenna for Satcom

In order to improve the availability of sequentially rotating array antennas, this paper proposes a miniaturized sequentially fed circular-polarization (CP) reconfigurable UHF antenna operating at 433MHz. The antenna adopts a ternary sequential feeding antenna structure to realize CP radiation. By folding radiating structure, the overall size of the antenna body can be greatly reduced, which is only 0.13λ
0
×0.13λ
0
×0.055λ
0
with λ
0
= 690 mm representing the wavelength of 433MHz in free space. To drive the antenna body, a feeding network according to spiral-shape Wilkinson power divider is implemented, where two double-pole double-throw (DPDT) switches are used. By switching, part of the feeding network can be reused to achieve phase direction adjustment, and then form a novel feeding structure with functions of adjustment between the left-hand CP (LHCP) and right-hand CP (RHCP). The overall design of the antenna is in simple structure, compact, easy to assemble, low in cost, and well in electrical performance. A prototype is designed and simulated, where the simulation results illustrate the proposed antenna has a well performance to fully meet the application of ground SatCom.