  Performing computational tasks with wave-based devices is becoming a
groundbreaking paradigm that can open new opportunities for the next generation
of efficient analogue and digital computing systems. Decision-making processes
for switching and routing of signal is fundamental for computing as it enables
the transfer of information from one to many (or single) blocks within a
system. Here, we propose and demonstrate a technique for the design of
pulse-based switching devices for the computing of fundamental decision-making
processes. In our technique, we encode information from multiple channels as
transverse electromagnetic (TEM) pulses of varying amplitudes and polarities
propagating through interconnected parallel plate waveguides modelled as simple
transmission lines. An in-depth description of our technique is presented
showing how switching and routing of information can be engineered by correctly
exploiting the linear splitting and superposition of multiple pulses traveling
through waveguide junctions. To demonstrate the potential of our technique for
computing, we develop two devices: a comparator which can calculate the largest
value between two real-valued numbers and a pulse director which exploits the
reciprocity of waveguide junctions to create a similar yet different
performance of a traditional AND gate (emulating its performance via our
analogue linear system). These findings may open new pathways and possibilities
for high-speed electromagnetic pulse-based computing systems.
