Wideband Non-Uniform Monopole Yagi Antenna

Since the born in 1920 s, Yagi antenna has attracted a lot of attention and many people have done research on it because it’s easy to fabricate and it has good performance in directivity. So far, the research on Yagi antenna is mature and it has been widely used in direction finding, communication, radars etc. Traditional Yagi antenna with metal rods and quasi Yagi antenna which usually printed on a dielectric substrate are two conventional forms of Yagi antenna. Nowadays the printed quasi Yagi antenna is very popular and it has many applications. However Yagi antenna with metal rods has been chosen for research’s need in this paper. This paper is mainly about a wide band monopole Yagi antenna on a finite size of ground at S-band and P-band and focuses on performance of end-fire directivity and low-profile with a rectangular array at P-band in a limited aperture. The major contributions are as followed:(1) A kind of monopole Yagi antenna on a finite size of ground at S-band is designed in this paper. The model is simulated and optimized by Ansoft HFSS, its VSWR is lower than 2 between 2GHz~5.2GHz, and the there’s no distortion with radiation pattern between 2GHz~4GHz.(2) The Yagi antenna at S-band is manufactured. By using Solid Works software, this antenna’s engineering drawing is designed and its object is made totally. Its VSWR is measured by vector network analyzer and radiation field is measured in dark room. The measurement and simulation results agreed well.(3) A kind of monopole Yagi antenna on a finite size of ground at P-band is designed in this paper. The model is simulated and optimized by Ansoft HFSS, its VSWR is lower than 2 between 320MHz~520MHz. With 6 units of this antenna, a linear array is made, its performance on radiation pattern is researched and the Active VSWRs on all ports are lower than 2.(4) The research about end-fire performance and low-profile on a linear array made by monopole Yagi antenna at P-band. The height of unit antenna is down to 100 mm, according to the control to the phase shift of all ports in array, the array’s beam direction approaches end-fire direction( ? ?90?) and the gain on the plane of end-fire direction(? ?90?) will achieve to the maximum, compared with the total gain of array, the gain on the plane of end-fire direction(? ?90?) is less than 3d B. 5 linear arrays are used to make a rectangular array, and its total gain is higher than 20 d Bi, when it scans within ?15? at horizontal direction, the Active VSWRs at all ports are lower than 3.