Miniaturization of a Multiband Pyramidal Antenna Using AMC Reflector for Satellite Applications

ABSTRACT In this paper, a modified trap‐loaded pyramidal antenna backed by a triband artificial magnetic conductor (AMC) reflector of size 0.42 λ L × 0.42 λ L × 0.15 λ L (where λ L is the guided wavelength at the lowest frequency) is designed for satellite applications (GPS/Galileo/MicroSat). The triband AMC reflector, consisting of 3 × 3 unit cells, is proposed to miniaturize and further reduce the backward radiation of a conventional multiband pyramidal antenna, originally backed by a bulky metallic cutoff open‐ended waveguide. Indeed, a significant reduction in the overall antenna size by 37%, 37%, and 67% along the x ‐, y ‐, and z ‐axes, respectively, has been achieved. A prototype of the proposed design has been manufactured, characterized, and compared with similar works reported in the literature. The antenna radiates circularly polarized electromagnetic fields with quasi‐hemispherical radiation patterns at multiple operating frequencies, achieved through quadratic phase excitations of its four feeding ports. The suggested design exhibits measured peak right‐handed circular polarization (RHCP) directivity levels of 5.12, 6.60, and 7 dB, along with significantly reduced backward radiation levels (LHCP directivity) of −8.06, −14, and −12.60 dB at the three measured operating frequencies: 1.20, 1.58, and 2.29 GHz, respectively. The proposed triband AMC‐based pyramidal antenna is compact, lightweight, and easy to integrate, making it well‐suited for satellite applications.