The CP Half E-shaped patch: Evolving from linear polarization to compact single feed circularly polarized antennas

The design of compact, broadband, circularly polarized (CP) patch antennas is a challenging and prevalent issue that has garnered the attention of antenna researchers worldwide. Recently, the CP E-shaped patch antenna was proposed to realize a broad CP bandwidth, but its large size can prevent its use in applications requiring small form factors. This work explores the possibility of a miniaturized design using only half of the E-shape to realize a compact, broadband CP Half E-shaped patch design. We highlight the design concepts and demonstrate the novel design with an example at 2.4 GHz WLAN. The prototype features 5.3% axial ratio and impedance matching bandwidth.