LAUSR

In this article, we present a method for designing miniaturized and broadband quadrifilar helix antenna, which has better bandwidth than other smaller antennas and more compact than larger bandwidth antennas. The antennae in this design have same size with axial lengths of 24 mm and diameters of 18 mm. The antennae are miniaturized by folded arms and dielectric loading. In both cases, a short pin is added to adjust the impedance matching and broaden the bandwidth. Inside and outside diameters of the loading dielectric cylinder are the parameters used for controlling the center frequency, which can be shifted between 1.2 and 1.8 GHz. An antenna with a central frequency of 1.5 GHz was simulated and measured to verify the design. In addition, this design could provide bandwidth of 100 MHz for satellite navigation application. Two antennae, operating at 1.227 and 1.575 GHz with 100 MHz bandwidth, are simulated. The 1.227 GHz antenna covers GPS L2, BEIDOU B2 and B3, GLONASS G2, and Galileo E5b bands. The 1.57 GHz antenna covers GPS L1, BEIDOU B1, B1C, B1I, and Galileo E1 bands.