# The Focusing Properties of a Modular All-Metal Lens in the Near-Field Region

## TL;DR

A new modular metal lens can adjust its focus in the near-field region, offering a low-cost and flexible solution for various applications like imaging and detection.

## Contribution

The novel modular all-metal lens design enables adjustable near-field focusing with reduced production costs and design flexibility.

## Key findings

- The lens achieves excellent focusing properties with adjustable focus positions between 0.30 m and 0.75 m.
- The modular design reduces production costs by 39.3% and increases design freedom.
- The lens is suitable for applications in antennas, microwave imaging, and biomedicine due to its transparency and lightweight nature.

## Abstract

This article proposes a modular and passive all-metal lens to achieve near-field focusing with adjustable focus. The proposed lens consists of all-metal units with the phase coverage range exceeding 360°, and the arrangement of units is guided by the phase compensation method. Specifically, using the strategy of module unit synthesis, the arrangement of lens units under different focuses can be assembled arbitrarily, which reduces the production costs by 39.3% and improves the freedom of lens design. The simulation and experimental results show that the lens exhibits excellent focusing properties and freely changes the position of the expected focus (0.30 m–0.75 m). Therefore, the modular all-metal lens designed in this article has the characteristics of high transparency and a high degree of freedom, which can provide low-cost and lightweight solutions for various applications in the field of antennas, such as near-field target detection, microwave imaging, biomedicine, and so on.