On aperture coupling based advanced design of antenna-filter-antenna elements in 60GHz compact system

This paper presents designs of the aperture coupling based passive antenna system in the 60GHz, referred to as the lens enhanced phased array (LEPA). The LEPA is a high-directivity steerable integrated system without penalties on the chip size and DC power consumption. The proposed lens consists of a 34×34 array of the antenna-filter-antenna (AFA) elements, utilizing one layer of 250um low-loss microwave laminate confined within two 18-um thick copper layers. The new configuration reduces the total thickness to 35% of the previous three-layer design. Direct coupling is integrated by slot antennas and CPW in metallic layers to rebuild the desired phase delay over the lens on basis of the relative phase shifts among four types of AFA elements. Good performance has been achieved in normal incidence as well as oblique incidences, up to 45°. Parallel plate modes between the two ground planes are eliminated by vias surrounding AFA elements, while surface wave modes may still produce unwanted blind spots and need to be suppressed.