Two-Dimensional Subwavelength-Focused Imaging Using a Near-Field End-Fire Antenna-Array Probe

A two-dimensional imaging technique is proposed based on an array of monopole antennas that produces a near-field subwavelength focal spot. The antennas are designed to produce an end-fire, rather than broadside, near-field beam in order to increase the degree of rotational symmetry in the structure. Since two-dimensional focusing does not automatically translate to two-dimensional imaging, symmetry was the key to extending subwavelength imaging to two dimensions. Simulations were conducted to demonstrate the improved resolution of the antenna array probe with a final minimum resolvable spacing of $0.256\lambda $ at a distance of $\lambda /4$.