Compact Omnidirectional Dual-Band Microstrip Antenna with Omega Slots for GPS L1/L2 Bands

Abstract

This study presents the design, fabrication, and experimental validation of a compact dual-band microstrip antenna optimized for GPS L1 (1575.42 MHz) and L2 (1227.60 MHz) frequency bands. The antenna was modeled and optimized using CST Studio Suite, focusing on key performance metrics such as impedance matching, gain, and dual-band operation. The proposed structure is built on an FR-4 substrate with a dielectric constant of epsilon r = 4.3 and a thickness of 1.6 mm, selected through detailed parametric analysis. To enhance dual-band operation, omega-shaped slots were incorporated into the patch design, which significantly improved resonance characteristics and minimized return loss. The antenna prototype was fabricated using a precision PCB milling process, and its performance was evaluated through vector network analyzer (VNA) measurements. The measured results showed excellent agreement with the simulations, yielding return loss values of -35 dB at L1 and -30 dB at L2, with corresponding gain values of 5.38 dBi and 5.33 dBi. Its omnidirectional radiation characteristics further enhance signal reception reliability in dynamic and multi-path environments. Additionally, the proposed antenna offers a compact, cost-effective, and high-performance solution suitable for various GPS-based applications, including navigation systems, tracking devices, and autonomous platforms.