60-GHz Wideband L-Probe Circular Slotted E-Shaped Patch Antenna Array

In this study, a 60-GHz wideband L-probe circular slotted E-shaped patch antenna array was presented. The novelty of this study can be summarized as follows: 1) An E-shaped patch was added to the L-probe to further expand the bandwidth of the existing L-probe patch. 2) The E-shaped slot was modified to a circular slot to improve the overall performance, including the radiation pattern, S
₁₁
, and cross-polarization of the original E-shaped patch antenna element. When compared to the original L-probe patch, the bandwidth was improved from 9.4% to 24.8% for the proposed antenna element. Furthermore, when compared with the triangular-shaped and rectangular-shaped slots, the cross-polarization level is improved by 3.5 dB and 2.5 dB, respectively. The proposed antenna was designed as a
$2\times 2$
array structure, and the size of the antenna array corresponded to
$\mathrm {6.4\,\,mm\times 6.4\,\,mm\times 0.375\,\,mm}$
. The measured results of the proposed antenna array revealed 11.42 dBi peak gain, 25.8% fractional 3-dB gain bandwidth, and 44.7% −8 dB S
₁₁
bandwidth.