Fig. 1. Typical structure of an inhomogeneous and asymmetric lens.

Fig. 2. Sample plane cross-section view of asymmetrical lens, whose thickness and aperture diameter are f and 2d. Each beam ray leaves from a point source at an angle α with respect to the z-axis and propagates through the lens.

Fig. 3. Trajectory of beam rays that started from the point source.

Fig. 4. (a) Refractive index profile and (b) electric field at 10 GHz.

Fig. 5. Stepped index lens antenna exited by a waveguide.

Fig. 6. Reflection loss of lens with WR90 antenna feeding.

Fig. 7. Electric field at a frequency of 10 GHz.

Fig. 8. Normalized radiation pattern of the lens antenna and source antenna at a frequency of 10 GHz. The directivity of the source antenna is 6.92 dBi and that of the lens antenna is 20 dBi.

Fig. 9. 3D radiation pattern loss of lens with WR90 antenna feeding at a frequency of 10 GHz.

Fig. 10. Normalization radiation pattern of lens on E and H planes.