Microwave beamforming lenses design in practice

In practical radar systems the coverage requirement is often tailored for higher definition and longer range at low elevation and lower accuracy at higher elevation angles. Four lenses are described with increasing attention having been paid to the amplitude distribution with each design. The first two designs were concerned only with generating a satisfactory phase ramp at the array for each beam but highlight certain drawbacks as a result of ignoring the amplitude performance. The third lens attempts to generate a tailored coverage by incorporating different beam ports within the same lens and this is taken a step further in the final design by using overlapping beam ports and a hybrid feed network