Design and analysis of a millimetre-wave high gain antenna

A broadband and high gain transmit array (TA) antenna, operating at 60 GHz, is proposed. To meet the design requirements of a TA antenna with polarisation-insensitive radiation performance, an optimal multi-layer unit cell (UC) is introduced. The dimensions of the UC are parametrically expressed to realise a linear transmission phase response with a variation range of 270 degrees and insertion loss <-3 dB over the desired frequency band ranging from 58 to 64 GHz. A new planar array composed of 2 x 4 aperture-coupled-patches interleaved with a soft-surface is also designed as a feed for the proposed TA. Furthermore, a hybrid method based on full-wave simulations and analytical formulations is developed to calculate the radiation characteristics of the TA antenna and the results are compared to the ones achieved with full-wave simulations. The designed TA antenna is fabricated and the measurement results are presented. The obtained results show peak aperture efficiencies of 38.48% (30.85 dB peak gain) and 32.37% (30.1 dB peak gain), and -1 dB gain bandwidths of 7.7 and 8.2% from the full-wave simulations and measurements, respectively. Such a broadband and high gain antenna is deemed to be suitable for mm-wave backhaul links in 5G cellular systems.