Wideband stacked microstrip patch antenna on thin PTFE substrate for millimeter-wave personal area network (mmWPAN)

Since FCC released the unlicensed use of 60GHz frequency band, more and more intensive researches and industry interests, including the IEEE standardization of millimeter-wave personal area network (mmWPAN) [1], have been done for the applications of high speed, short distance wireless communication. An antenna with high gain (more than 10dBi) or beam steering feature is the most expected in such a system to provide enough system link budgets [2]. In [3], a simple stacked microstip antenna with two driving patches, fabricated on the Teflon substrate with the thickness of 0.254mm, was reported to have 9 dBi gain covering all frequency bands (57–66GHz), allocated in Japan, US and EU. However, our recent work [4] shows that the basic circuit components, such as bends, folded lines, suffer from quite high losses on the 0.254mm-thick substrate. This will cause serious problems in the future circuit integration. To reduce the losses of feeding networks caused by thick substrate, a thinner substrate with 0.127mm thickness is employed in this paper. However, antenna on the thinner substrate has narrower bandwidth and lower gain. Stacked patch antennas with different configurations based on the work [3] will be presented first to show the frequency bandwidth characteristics and radiation performances on the 0.127mm-thick substrate. Aiming at obtaining wideband and higher gain, a series-parallel mixed stacked patch antenna array is also proposed as in Fig. 1.