A corner expanded slot antenna loaded with copper strips for dual-band circular polarization characteristics

Abstract

In this article, the design and implementation of a dual-band circularly polarized (CP) microstrip line fed square slot antenna with compact size is proposed. The proposed CP antenna consists of a square slot antenna with a pair of symmetric rectangular extensions on opposite corners and loaded with an array of inclined and truncated rectangular copper strips. The square slot with diagonal extensions resonates at 2.24 to 2.62 GHz with a 3 dB axial ratio (AR) bandwidth of 15.7%. Besides, loading it with an array of inclined and truncated rectangular copper strips helps produce a resonance at higher band with CP. The higher band operates between 3.26 and 5.18 GHz and centered at 4.52 GHz, with a 3 dB AR bandwidth of 45.5%. The polarization sense and resonant frequency of the proposed antenna can be independently tuned depending on the position and dimensions of the slot and strips, respectively. The proposed antenna is fabricated and measured in terms of impedance bandwidth, axial ratio bandwidth, peak gain, and radiation efficiency. Good agreement between the simulations and measurements of the prototype is obtained. 2019 Wiley Periodicals, Inc.