Application-Friendly Improved Designs of Single-Fed Circularly Polarized Microstrip Antenna [Antenna Applications Corner]

Truncated-corner probe-fed (TCPF) patches are popular for their simple design that provides circularly polarized (CP) radiation with a very low axial ratio (AR). For a thin substrate (~0.026λ
_g
), this antenna provides approximately 0.3% CP bandwidth (BW) (AR <; 3 dB along with S
₁₁
<; -10 dB). However, as the substrate thickness is increased for enhancing the matching BW, an offset among the frequencies featured with minimum AR and optimum S
₁₁
is observed. This degrades the effective BW, with an overlapping of both S
₁₁
<; -10 dB and AR <; 3 dB.