Circularly Polarized Compact Monopole Antenna with an Offset Microstrip Feedline for C-Band Applications

This paper presents a circularly polarized (CP) compact monopole microstrip feed antenna for C-band applications. AR < 3 dB is achieved by simple L-shape protruding stub from the ground plane in the direction of the center of the slot and after then wide slot fed with an offset microstrip feedline at an offset distance d, beneath the protruded stub. Compact CP microstrip antenna is proposed with dimension 25 mm × 25 mm. Simulated results manifest that the proposed antenna |S11| ≤ –10 dB impedance matching bandwidth is 97.43% (3.5–10.15 GHz) and obtained ARBW is about 43.94% (4.67–7.3 GHz). Obtained simulated peak gain of compact CP antenna is about 4.43 dB at 7.6 GHz. The proposed compact monopole CP antenna is found to be satisfactory for C-band applications.