A New Type Of Broadband Planar Array Antenna Is Studied

Associated with the rapid development of modern radar and communication technology, various microwave and RF systems have more stringent requirement2on antennas. Antennas with inertialess scanning, special shaped beam, high directivity or gain, etc. are often required. Under these circumstances, antenna arrays are needed. Wideband antenna arrays are widely used in broadband communication, electronic countermeasure and electronic warfare, Surveillance/guidance/search/tracking radar, wideband or ultra-wideband radar and many other fields. Additionally, planar antenna array has the properties of low profile, conformal structure and low cost. Thus, this research is of great importance in engineering.However, design of antenna element, coupling between elements and feed network in wideband planar antenna array are still difficult to deal with.The main work of this paper is as follows:Firstly, design method of traditional Vivaldi antenna is analyzed. The analyses of radiation principle, transmission characteristics of slotline, exponential tapered slotline and slotline-microstrip balun are included.Secondly, a novel planar-fed spiral antenna is designed, and it can be used as element of wideband planar antenna array. The analyses include principles of radiation, design of spirals and wideband CPS-microstrip balun.Thirdly, a power divider based on microstrip-slotline coupling is designed. The bandwidth extends from3GHz to11GHz. A microstrip-slotline coupled power divider with isolation is also analyzed. It is designed and simulated in the identical substrate with antenna elements for the convenience of further design of feed network and antenna array.Finally,1×8and1×4Vivaldi antenna arrays with novel feed network based on microstrip-slotline coupled power divider are designed. They have satisfactory wide bandwidth and high gain.