Circularly polarised antenna with wide harmonics suppression by two angled C‐shaped structures

Abstract

In this Letter, a circularly polarised (CP) antenna is proposed. The proposed antenna is realised by combining two angled C-shaped structures. By setting different widths (W L and W R) for the left and right angled C-shaped structures, respectively, an asymmetric structure is obtained. Therefore, the proposed antenna exhibits CP characteristics. From repeated simulation results, the authors find that the optimum ratio W L : W R to make the proposed structure operate as a CP antenna is 5: 8. Moreover, the measured reflection coefficient is lower than −2.4 dB within a stopband up to 12 GHz. This means that wide harmonics suppression (up to the fifth harmonic) is successfully achieved.