Multi-beam Transmitarray Antennas for 5G Radio Access at Ka-Band

A beam scanning transmitarray antenna (TA) working in the 27.5-29.5 GHz frequency band is presented here. The unit-cell is made of three stacked meshed circular rings printed on Diclad substrates, and provides a 300° phase-shift for an insertion loss lower than 1 dB at 28.5 GHz. The TA is illuminated by a
$2\times 2$
-element array of aperture-coupled stacked microstrip patch (ACMP), whose location is shifted in the focal plane to scan the antenna beam in H-plane from −30° to 30°. A TA prototype with a diameter of 9.9 wavelengths has been designed, fabricated and tested. A broadside gain of 25 dBi and −1 dB gain bandwidth of 1.8 GHz have been obtained experimentally.