  Acoustic devices offer significant advantages in size and loss, making them
ubiquitous for mobile radio frequency signal processing. However, the usable
bandwidth is often limited to the achievable electromechanical coupling,
setting a hard limit using typical transducer designs. In this work, we present
an ultra-wideband transducer design utilizing a tapered electrode configuration
to overcome this limitation. The design is realized on a lithium niobate (LN)
on silicon carbide platform, utilizing a combination of first and higher order
shear-horizontal modes to generate the ultra-wideband response. The
implementation shows a fractional bandwidth (FBW) of 55% at 2.23 GHz with an
associated insertion loss (IL) of 26 dB for the measured 50 ohm case. Upon
improved impedance matching, this performance could be improved to 79% FBW and
an IL of 16.5 dB. Upon further development, this ultra-wideband design could be
reasonably scaled towards improved FBW and IL trade off to enable improved
usability for cases where bandwidth should be prioritized.
