Compact Inverse-Designed Metalens for Millimeter-Wave Field Enhancement

Enhancing fields is an important task in millimeter-wave applications, such as nondestructive microwave inspection, metamaterial sensing applications, or millimeter-wave imaging. This demand for compact yet high-performance devices for field enhancement operating in the millimeter-wave regime has led to innovative approaches regarding lens design. State-of-the-art lens designs in this wavelength regime tend to be bulky and operate in the far field, making them unsuitable for small form factor applications. In this context, formulating the required functionality and algorithmically looking for the desired material topology is an inversion of the standard approach. This paper presents an inverse-designed field-amplifying metalens operating in the near field of a 60GHz patch antenna. With a size of about three times the wave length, the given structure promises good performance while maintaining a smaller form factor than conventional solutions. It yields an enhancement of the power amplitude by over 7dB.