Broadband and High-Gain High-Order-Mode Fed Open-Ended Waveguide Antenna Array for Millimeter-Wave Applications

In this communication, a high-order-mode (HOM)-fed open-ended rectangular waveguide antenna with high gain and broadband is proposed for fifth-generation (5G) applications. A miniaturized HOM cavity with four slots introduces hybrid modes of
$TE_{340}$
and
$TE_{140}$
, which act as a low loss feeding network. Furthermore, an open-ended waveguide is loaded above the HOM cavity to widen the impedance bandwidth. Compared with
$TE_{340}$
HOM, hybrid modes of
$TE_{340}$
and
$TE_{140}$
HOM provide more compact size and higher gain. For the proof of concept, a
$4\times $
4 antenna array is designed and fabricated. The measured impedance bandwidth is 28.1% from 32.85 to 43.6 GHz. The measured peak gain is 21.7 dBi. Great compatibility between simulated and measured results is achieved.