Improved performance millimetre‐wave antenna array by using artificial materials

Abstract

A millimetre-wave (MMW) 4 × 2-element antenna array integrated with a soft surface structure is presented. The proposed antenna is alternatively interpreted as an array of overlapped eared-aperture-coupled-patch-antenna, fed by strip-line feed-network through a low loss and wideband strip-line-to-grounded-coplanar-waveguide transition. It is shown that, compared to a 4 × 4-element conventional planar array with a given aperture size, eight radiating elements are required to achieve an almost same directivity/gain by utilising the soft surface structure between elements of the array. By reducing the number of excited elements with this method, the feed-network is simplified. Furthermore, being more noticeable in the E-plane, where soft surface structure is used, the side lobe level is improved in both E- and H-planes. Enhancements of matching and directivity/gain bandwidths are other advantages achieved with the proposed approach. In addition, it is feasible to use the proposed soft-surface structure in developing larger antenna array packages that can be integrated with other parts of a radio frequency circuitry by using MMW interconnection technologies.