Bandwidth Improvement of Broadband Circularly Polarized Antenna for L Band Application

This paper presents the bandwidth improvement of broadband CP antenna. This improvement uses a groundplane modification and a combination of slotting and truncated corner in patch antenna. It has some development stages to get the optimized groundplane and the optimized slotted-truncated corners of patch antenna. The patch antenna has a size of $30 \times 48\times 0.035,\ \text{mm}^{3}$ . The proposed broadband CP antenna has an impedance bandwidth $(\mathrm{S}11<-10,\ \text{dB})$ of 832 MHz and an axial ratio (AR) bandwith (< 3 dB) of 832.3 MHz, respectively. It is about 65.3 % of operation frequency. The combination of diagonal slot and truncated corner creates a wider AR bandwidth of 19.8 MHz compared to the unslotted and untruncated patch antenna, it has a broadband bandwidth of 851.9 MHz. This proposed broadband CP antenna also has a low VSWR value of 1.26 in operation frequency of 1.275 GHz. It has good performance and meets a required broadband bandwidth in L band spectrum.