Resolution Enhancement of Phase-Conjugating Lenses by Using Signal Processing Algorithms

In this letter, we show how we can improve the resolution capability of a phase-conjugating lens by employing a signal processing algorithm, namely the Minimum Residual Power Search Method (MRPSM), and we apply it for subwavelength imaging in the microwave regime by combining it with the well-known phase conjugation (PC) technique, which has been extensively used in the electromagnetics area for imaging purposes. We show that by using such a combination, we can achieve subwavelength resolution on the order of λ/10, even if the phase-conjugating lens or the measurement plane is located in the far-field region of the source. We describe the proposed algorithm in detail and study its ability to resolve at the subwavelength level, as well as its computational efficiency in a comparative manner.