Reaserch On Compact Broadband Multiband Microstrip Antennas For Navigation Application

The satellite navigation technology and four main satellite navigation system are simply introduced. Then the development status of antennas used in navigation system were studied according to the demand of satellite navigation technology. The basic theory and main analysis methods of microstrip antennas are discussed.Methods to achieve broadband compact microstrip antennas are studied in this article. Finally, based on what we have studied, three microstrip antennas with different characteristics are designed..Firstly, a multi-band microstrip antenna is designed.By using a multi-layer stack structure,the characteristic of three bands in the B3, L and S is achieved. And the antenna performance meets the design requirements in VSWR, AR and gain.A compact microstrip antenna is presented with a short load structure. The antenna size is reduced to 75mm*75mm*19.5mm at a center frequency of 1.35 GHz. By increasing the height of the antenna, and using the L-type feed structure, a broadband characteristic is achieved.The the boresight gain is greater than 2d B and gain at low elevation angle(elevation angle of 20 degrees) is greater than-1d B, while the frequency range from1.1GHz to 1.6GHz.The VSWR is less than 1.5and the axial AR is less than 3d B.To meet the requirement of miniaturization,a miniature antenna for Navigation application is presented.The antenna layout employs lumped capacitors and inductive pins over a moderately high permittivity Rogers TMM10 i substrate to concurrently achieve the goals of size miniaturization,high radiation efficiency,and proper spacing of B3 band resonance frequencies.Air substrate is also used to decrease the weight of the antenna without slowing down the antenna performance. The size of this antenna is.It operates with >50%less area as compared to conventional B3 band patch realized over the same substrate. The simulated RHCP gain is more than 5.5d B.The antenna operates with more 90% B3 band simulated radiation efficiency. The VSWR is less than 1.5, and the AR is less than 3d B.