mmWave Metal Bowtie Slot Array Element Integrating Power Amplifier MMIC via On-Chip Probe to Enhance Efficiency and Bandwidth

A Ka-band wideband, wide-scan range, and high-efficiency active integrated array element with a contactless transition at the antenna–power amplifier (PA) interface has been developed with the aid of a joint optimization design flow. This element employs a metal cavity-backed bowtie slot to realize the desired optimal interface impedance over a wide frequency band and scan range. The contactless transition in the form of an on-chip E-plane probe provides an electromagnetic coupling to the slot to avoid lossy and narrowband wire bonding, where the probe is integrated onto the custom-designed gallium arsenide (GaAs) pseudomorphic high-electron-mobility transistor (
${p}$
HEMT) PA monolithic microwave integrated circuit (MMIC). The integrated design features a peak power efficiency of 40%, a fractional bandwidth of 11.3% (power efficiency
$\geq 20\%$
), peak effective isotropic radiated power of 28 dBm, and a scan range of
$\pm {\mathrm {55}}^\circ $
and
$\pm {\mathrm {40}}^\circ $
in the two principal planes at the 1dB compression point. The behavior of this element in the infinite connected-slot array environment is emulated and experimentally verified by the active waveguide simulator technique.