Design of a dual-band GPS antenna

Abstract

Circularly polarized (CP) patch antennas are popularly used in the modern satellite communications (like GPS) due to their attractiveness such as low profile, ease of fabrication and good radiation characteristics, etc. For conventional GPS patch antennas, because of the necessity of small module size, a high permittivity of microwave substrate would be employed for the size reduction. However, it causes the increase of the materials cost. In this project, a method of combining "cutting slot" and “embedding tail” on the patch for having a low-cost, small size, low-profile CP patch antenna is introduced. Through the proposed method, the antenna achieves a large percentage in size reduction even only employing a low permittivity substrate. The antenna finds many good electrical characteristics including: wide radiation beamwidth, reasonable axial ratio bandwidth and symmetric radiation pattern. In order to verify the proposed design, a simulation study by commercial EM package, IE3D, and an experimental study are conducted. In addition, a dual-band GPS antenna is fabricated based on the proposed design. The antenna finally finds a potential application in the Beidou GPS system (GPS system in China).