Design Of Multi-band Omnidirectional GNSS Antennas

The application of Navigation Satellite System in navigation and positioning has gone deep into people’s daily life and production, China is committed to developing our own Compass Navigation Satellite System (CNSS). In order to improve the positioning accuracy, and to receive more satellites, the design of multi-band antenna and antennas covering the CNSS bands has become a trend. For some specific applications, such as some high-speed rotating carrier, missile-borne and airborne, and the application in reconnaissance and interference satellite navigation signals, this kind of antenna has seldom been reported, because many factors do need to be considered.Omnidirectional antenna application in satellite navigation system is studied in this thesis. Firstly, the overview of some basic parameters in antenna design is introduced. And succeeded by that, the structures and properties of two simple antenna, monopole and conical antenna, used in this thesis are presented. Then a loop-dipole model is proposed as a theoretical basis of omnidirectional circularly polarized antenna design and several design methods of omnidirectional circularly polarized antenna commonly used at present are summarized. Eventually, based on these approaches, one multiband omnidirectional Global Navigation Satellite System (GNSS) antenna for artillery projectile applications and two dual band circularly polarized omnidirectional GNSS antennas are proposed.The first antenna which is designed to cover CNSS B3, CNSS B1 and GPS L1 is a compact multiband omnidirectional GNSS antenna for artillery projectile applications and consists of a single-cone antenna and T-shaped monopole. The second antenna is a dual band dual circularly polarized omnidirectional GNSS antenna and the lower band GPS L2 is right hand circularly polarized (RHCP), the other band CNSS L is left hand circularly polarized (LHCP). The proposed antenna has favorable symmetry capability with excellent omnidirectional circularly polarized characteristic. The third antenna is a dual band RHCP omnidirectional GNSS antenna by means of adding a bend branch based on the second antenna. Three antennas are analyzed in detail, fabricated and tested. Measured and simulation results are in good agreement.