Defocused Cylindrical Luneburg Lens Antennas With Phased Array Antenna Feed

In this paper, a defocused cylindrical Luneburg lens antenna with phased array antenna (PAA) feed operating at 10 GHz is proposed. After equivalent and defocusing procedures, a defocused lens is developed, effectively dispersing the energy over the focal area. Furthermore, a 19-element dipole PAA, which has been partitioned into three linear subarrays, illuminates the defocused lens with the weighted excitation coefficients optimized by the introduced active element-lens pattern (AELP) method. Comprehensive analyses of the AELP method and classical conjugate field matching (CFM) method on deploying the PAA feed excitation coefficients are also performed. The simulated results show that the proposed PAA-fed defocused lens features a high-precision scanning across an ultra-wide angular range of ±81° with a 21.1 dBi peak gain, 3/7.5 dB gain drops as scan to 75°/81°, respectively. Besides, against traditional cylindrical Luneburg lens with switched feed elements, 5.4-3.3 dB gain enhancements and 11.9-6.6 dB effective isotropic radiated power (EIRP) improvements are obtained as the beam scans from 0° to 74°, except for the expansion of the maximum scan angle to 81°. In the experiment, the AELPs, as well as the whole PAA-fed defocused lens integrated with active modules for broadside scan, are measured, accurately evaluating the proposed design.