Abstract: In various implementations, designs of relatively simple ultra-wideband STAR front-end systems are provided. For example, such systems may include implementations utilizing a plurality of antenna arms in which a first portion of the arms is configured to transmit and a second portion of the arms is configured to receive. In one implementation, for example, a co-channel simultaneous transmit and receive (STAR) monostatic aperture configuration includes a single-polarized multi-port monostatic co-channel simultaneous transmit and receive (c-STAR) spiral antenna aperture. Other examples are also provided.