The Study Of Dual-frequency And Band-notched UWB Microstrip Antenna

The antenna in radio system is used to transmit and receive electromagnetic wave. Withthe rapid development of modern wireless communication, it puts forward more requirementson performance and structure of the antenna. For example, the antenna should have thesecharacteristics of miniaturization, circular polarization, etc. Microstrip antenna has theseadvantages of miniaturization, low profile, low cost and easy of manufacture, also it is easy torealize circular polarization, easy to work on dual-bands, and is convenient to work onbroadband, etc.Combining with the characteristics of GPS (global positioning system (GPS), WLAN(wireless local area network), and UWB (ultra wideband) system, this article studies thedual-frequencies and ultra widedband microstrip antenna; It Puts forward and designs twonew dual-frequencies microstrip antennas and a UWB microstrip antenna with band-notchedcharacteristics.A dual-bands antenna with a structure of a single substrate and the radiationpatch slotting a square annular slot, it has realized to work on two frequencies of the GPS(1.575GHz) and WLAN (2.45GHz), and in the GPS working frequency, it has circularpolarization characteristics; The second dual-bands antenna with the structure of cascadingtwo substrates, single microstrip-fed port, combining with the characteristics of slot antennasand aperture coupling fed antennas, it can simultaneously work on GPS and WLAN. Theantenna has an approximate hemispherical right-handed circularly polarized radiation patternin the1.575GHz and has an approximate linear polarization omnidirectional radiation patternin the2.45GHz frequency. The third microstrip antenna is a UWB antenna with band-notchedcharacteristics, it is fed by a coplanar waveguide with a circular patch, on which it is slot aninverted u-shaped slot. The antenna implements the impedance bandwidth of3.1GHz to10.6GHz, and forms a notched band at the band of5.0GHz to5.95GHz. In this paper, the antennaparameters are simulated and tested, the results showed that the antenna basically meet therequirements of the wireless system.