Pencil-beam steering is an important antenna
requisite for the new generation of mobile communications. Flat
panel antenna solutions are quite popular due to their low
footprint, small volume, and agile steering response. However,
their use is limited by the losses of the feeding network, power
consumption and high cost, which are aggravated with the
increase of the operating frequency. Hence, mechanical steering
solutions can still be a viable alternative for cost-driven
applications. Transmit-arrays are a type of passive flat
(meta)lens antenna that can provide sufficient design flexibility to
circumvent some of shortcomings of more classical mechanical
scanning approaches, including antenna bulkiness, beam
aberrations and limited scanning range. In this communication
we will survey some of the solutions developed by the authors in
the millimeter wave regime which can pave the way for future 6G
low cost antenna designs.