  When using ultra-wideband (UWB) signaling on massive multiple-input
multiple-output (mMIMO) systems, the electromagnetic wave at each array element
incurs an extra propagation delay comparable to (or larger than) the symbol
duration, producing a shift in beam direction known as beam squint. The beam
squinting problem degrades the array gain and reduces the system capacity. This
letter proposes a novel transceiver design based on lens antenna subarray (LAS)
and analog subband filters to compensate for the beam squinting effect. In
particular, the proposed design aims to divide the UWB signal into narrowband
beams and control them with a simplified exhaustive search-based precoding that
is proposed to align the beam angle to the target direction. The design is
analyzed in terms of beam gain, complexity, power consumption, and capacity,
demonstrating significant performance enhancement with respect to the
conventional system with uncompensated beam squinting problem.
