Base station antenna systems with built-in processing for the reduction of the effects of hardware imperfections

The effects of many mechanical and electrical manufacturing imperfections of antenna arrays can be minimized with an internal pattern database. Such deficiencies are the non-idealities of amplitude and phase characteristics of sub-arrays and active modules. The idea of the suggested method is to store measured pattern characteristics into the antenna's internal memory at delivery and later, during operation, to use this data to support, for example, a beam forming algorithm, or just to create a static optimum. Thus, the antenna "knows" its behaviour. This method is both more cost-effective than a fine tuning of the hardware items on the production line, and often, the only choice, if relatively inaccurate sheet metal antennas are considered; but naturally, requires some active RF hardware. Our tests demonstrate S-band patterns within 2 dB or 3/spl deg/ of the theoretical ones if an EPROM database at 1/spl deg/ intervals is used. The improvement of the depth of wanted minima can exceed 12 dB.