A High Gain Multi-Port Series Fed Array Realized with Micromachined Low-Cost 3D-Printed Substrate

A low-cost three-port series-fed antenna array with pattern diversity for WLAN applications is presented. The three antennas resonate at 5.8 GHz with 12 dBi antenna gain. The antenna substrate consists of an air cavity within the substrate, which is introduced to enhance the gain and radiation efficiency. The principle of micromachining was used to realize the substrate characteristic that lowers the dielectric constant, compared to a conventional non-micromachined substrate. The antenna uses scaled parasitic patches as a superstrate to improve and equalize the gain of the respective antennas when the antenna beam scans through +18(0), 0(0), and -18(0). The parasitic patches as a superstrate were found to have low scanning loss when the antenna beam is tilted from the broadside. The proposed superstrate design enhances the gain at the broadside and oblique radiations making the design more versatile as the gain enhancement becomes invariant to the incidence angle. The planar superstrate enhances the gains of three antennas with 2.4, 2.8, and 7.1 dB so that the final antenna gain is equalized to 12 dBi at the three ports. To validate the design, the antenna module is fabricated on the polylactic acid (PLA) substrate using the industry-standard photolithography process.