Research And Design Of A New Hemispherical Helical Antenna

With the rapid development of information technology today, in addition to the transmission carrier of high requirements for information, antenna plays an important role in the aspects of the information received and transmitted; so the requirements of antenna performance is higher and higher. According to the communication needs of different antenna used for receiving the information, the micro strip antenna, dipole antenna, band notched antenna has been widely used in the wireless communication daily. But in some communication systems, such as:satellite communication and the satellite positioning system, in order to make the terminal information exchange more concise, the area which the antenna covers is needed to be very big; so the general antennas can’t meet the needs of communication.This kind of communication antennas, the polarization and the volume of the antenna has very strict requirements, expectations of the size of the antenna which needed to be as small as possible and the circularly polarized wave which the antenna should radiate. Therefore the radiation spiral antenna and the circularly polarized wave are widely used. The traditional spiral antenna, generally cylindrical, conical, or quasi conical shape, they all have certain limitations in the antenna beam width and bandwidth. Then, people put forward the spherical helical antenna and the spherical helical antenna with circular polarization, axial radiation, beam width etc., which is very suitable for the satellite communication. Based on the spherical helical antenna, some people propose a new hemisphere antenna with smaller section of the plane spiral; the wires wound on the Hemispherical Helical Antenna; when compared to traditional radiation, this antenna not only has excellent characteristics but also has smaller size.With the commercial software Ansoft HFSS, the paper analyses of the way in which the antenna radiates and does the simulation based on the model of Hemispherical Helical Antenna; when doing the design, the main concern is the relationship between the number of helical turns and the number of helical arms; the paper also discusses the relationship in the number of helical turns, the number of helical arms and the self resonance under the condition of low frequencies.Finally, the paper proposes a four-arm hemispherical helical antenna with the gain is about3.5dBi and the radiation resistance is near50Ω; the resonance point is at249MHz, ka is less than0.5, the antennas are self resonant and the efficiency of radiation is95％.