Plannar antenna for L1 and L2 GPS bands applications

Abstract

This paper presents the development of an antenna with circular polarization and double resonance using a substrate of low dielectric constant and low price, showing comparable results in front of conventional designs. The design is made up of two rectangular patches isolated by an air gap including two triangular cuts and two parasitic patches located in the opposite direction giving a certain degree of additional freedom which allows a suitable axial ratio and an acceptable coupling to the desired frequencies. The antenna was optimized by means of parametric analysis carried through diverse variables which belong to geometry. The implemented prototype allows the simultaneous operation of the antenna in the GPS (Global position systems) bands of 1,227 GHz (band L2) and 1,575 GHz (band L1). The antenna shows a measured impedance bandwidth of about 18,03MHz (fc1 = 1,227GHz) and 17,66MHz (fc2 = 1,575GHz), for VSWR ? 2:1 (Voltage Standing Wave Ratio), the simulated results for antenna gain were of 5,4dBi and 6,8dBi and axial ratio of 8,1MHz and 10,2MHz in the L1 and L2 bands respectively. The numeric simulations agree well with the measurements on the experimental prototype proving the antenna behaves according to what was expected.