Shaped S-band Array Antenna Developed

The S-band beam-forming array is for receiving front-end of a distributed network radar system, which uses many small high mobile, multi-functional, modular nodded radar netting to realize target detection and tracking. This radar system can observe the same geographical area through different perspective, and therefore can enhance the two-dimensional imaging resolution through data integration of groups of echo Doppler spectrum. Thus this system often requires the array antennas to radiation some specified shaped pattern, and possess good electrical properties.This paper will focus on discussing the entire development job of S-band shaped-beam array antennas. And the main research contents and contributions are as follows:1. The linear array with a horn box can be equivalent as a planar array by using classical methods and the mirror theory. We get the radiation pattern in functions of two main polarizations in this way. At the same time, a quasi-global optimization algorithm of shaped-beam array antennas is adopted to optimize the amplitude and phase of excitations. In order to reduce the phase imbalance between various ports of power divider and broaden the bandwidth of the beam-forming pattern, the phase optimization results can be controlled to an appropriate range.2. This paper analyses the impact of the magnitude, phase and installation position tolerances on sidelobe of shaped-beam pattern using a normal distribution with zero mean as error mode. Also the sensitivity of different position units in the array to various errors is discussed and some meaningful conclusions are obtained.3. Power divider is designed based on the optimized amplitude and phase distribution of shaped-beam pattern. A new distribute method is introduced to assign the distributions of phase to each power divider, which can make the feed network become more compact. At the same time, in order to make the array energy more focused, the rectangular horn slot added to two sides of array be designed rationally.4. It is very important to analyzing and adjusting the mutual coupling between elements in array. The element antenna should be resized in the array to compensate the mutual coupling and reduce the aberrance of the element's active impedance.5. A reasonable connection structure need to be designed between element antennas and power divider because of an integral design is not be used in this paper. This structure not only enhances system stability and reliability, simultaneously making the overall structure of relatively compact, but also reduces the unnecessary input loss and ensures that the realization of various indicators with beam-forming array.