A new I slotted compact microstrip antenna for L1 & L2 bands

A new high gain dual-band circularly polarized with a small frequency ratio is proposed for Global Positioning System (GPS) applications covering L1 and L2 frequencies of 1.575GHz and 1.227GHz. The antenna is consists of I slotted compact microstrip antenna with two truncated corners square patches that overlapped without an air-gap. The overall antenna size is 0.315λ₀ × 0.309λ₀ × 0.016λ₀ at 1.227GHz and 0.302λ₀ × 0.302λ₀ × 0.016λ₀ at 1.575GHz (where λ₀ corresponding to center frequency). The design achieved an impedance bandwidth of 20 MHz from 1.22 GHz to 1.24 GHz for the lower band, while upper band covers 97.88 MHz (from 1.562 to 1.66 GHz) with maximum gain of 7.27dBi and 6.87dBi in the lower and upper frequency band respectively. The bandwidth (VSWR ≤ 2) is 1.57% (1.222 GHz to 1.2414 GHz) for L2 and 6.27% (1.5617 GHz to 1.6626 GHz) for L1. The details of the antenna design are shown, and the results with low-profile characteristics make the antenna suitable for GPS applications.