A printed array antenna for multi-layer PCB design

This paper presents a design of 1×4 printed array antenna excited by proximity coupling. The gain of patch antenna built on thin substrate is usually inferior to the one with thicker substrate of the same material. The goal of this work is to design an antenna with realized gain less responsive to substrate thickness. Patch antenna fed by two-layer proximity coupled feeding line is introduced to alleviate gain degradation caused by thin substrate. Proposed antenna is compared with conventional patch antenna in simulation. 1×4 array antenna is fabricated on multi-layer PCB to validate our design. Array antenna fabricated on FR-4 substrate exhibits good radiation characteristics and a flat gain response from 7.7 to 8.3 GHz is measured. Measured radiation patterns of array antenna are similar to simulations.