The Design And Implementation Of L-band Secondary Anti-collision Radar Phased Array Antenna

Phased array radar was first used in military equipment, along with the progress of science and technology, the related technology is also applied to civil aviation passenger plane system, and used in the design of airborne collision avoidance system.Air traffic safety is the current hot topic, so the performance of the airborne collision avoidance antenna is crucial, must be a real-time detecter to the airliner flight orbit, and put out an alarm to avoid colliding with them .Therefore, it is imperative to develop a TCAS antenna which has a built-in electrical control, can realize directional and omnidirectional radiation mode and has low profile, small size,light weight and reliable performance.In this paper, a L-band secondary anti-collision phased array antenna is designed,working in civil aviation communication frequency (from 1.03 GHz to 1.09GHz), the work completed mainly includes:1. Design a new type of antenna array, which size is 2/5 smaller than the similar foreign antenna independently;2. Design a new type of active phased array antenna feed network, firstly, it realizes the function of phase and amplitude weighting of the antenna array, it can achieve 5 kinds of beam scanning, power capacity reached 200w, secondly, its structure is miniaturized, and reduce the use of lumped elements at the same time;3. Use the gradient feeder placed in the form of planar inverted F antenna array units, and join the parasitic unit, expand the bandwidth, realize its miniaturization at the same time.Laboratory test results show that: the omni-directional and directional VSWR less than 1.6,form the band width form 1.02GHz to 1.1 GHz ,already 90MHZ bandwidth, to some extent, prevent the bad effect of frequency offset on the antenna system work. Directional beam width is greater than 90°, gain greater than 2dB.Omni-directional pattern beam width 360°, gain greater than -1 dB, out of roundness is lower than 1.6dB.The above indexes meet the requirement of index design in this paper, and can be put into use.