Efficient, Low-Cost Integrated Waveguide-Fed Planar Antenna Array for Ku-Band Applications

Low-cost printed circuit board waveguide (PCB-WG) technology is employed to develop new waveguide-fed microstrip antenna arrays with low profile and light weight while maintaining high efficiency and gain at 12.5 GHz. The proposed corporate feed network has two parts: on the antenna layer, microstrip lines are used to form a 2 $\times$ 4 sequentially rotated subarray of circularly polarized microstrip patches and on the feed layer SIW is utilized to combine any number of these subarrays to form a larger array. Since SIWs transmit the power over a large portion of the feed network, losses are substantially reduced and spurious radiations from feed circuit are eliminated. Several microstrip arrays with PCB-WG feed were designed and fabricated using standard PCB process. Comparing the results with those of a hybrid array with conventional waveguide feed shows that there is only a negligible degradation in gain and efficiency when bulky and expensive aluminum waveguides are replaced by PCB-WGs.