EVALUATION OF GAIN ENHANCEMENT IN LARGE MICROSTRIP ANTENNA ARRAYS FOR MM-WAVE APPLICATIONS

摘要

Microstrip patch antenna arrays (MPAAs) have been designed with different numbers of patch elements and substrate heights to evaluate the antenna gain enhancement for millimetre-wave (mm-wave) (30-300GHz) applications. The patch antenna size extension method is employed to improve the tolerance in fabrication with low cost printed circuit board (PCB) etching process. Initially, the designing concept is analysed at 10GHz frequency and then the optimized high gain (～21dBi) array is fabricated and tested at 60GHz-band (57.24-65.88GHz). It has been found that the loss contribution due to the long feeding transmission line (TL) network in large MPAAs severely degrades the antenna gain when thick substrate is deployed. However, by employing relatively thinner substrate gain can be significantly enhanced in large arrays but cost has to be paid in terms of narrower return loss (S11) bandwidth (BW) and higher side lobe level (SLL). Finally, the optimized MPAA has been redesigned at 100GHz frequency on a thin PCB substrate and a good relation has been achieved between the antenna results obtained at 100GHz and 60GHz frequencies.