Waveform-selective devices for antenna applications

In this contribution, we investigate several examples of antenna applications of waveform-selective devices, i.e., structures exhibiting different responses depending on the waveform of the incoming waves. In particular, as a first example, we describe an open-ended waveguide capped with an iris band-pass filter loaded with a lumped-element circuit. Thanks to the frequency- and time-domain selectivity properties of the loaded iris, the aperture antenna exhibits different radiating patterns depending on the waveform of the transmitted/received signal. Then, the same lumped-element circuit is used to design an antenna that is made invisible/visible to either a short pulse or a continuous signal. Exploiting a peculiar meandered cloaking metasurface loaded by the lumped-element circuit, the cloaking effects is automatically turned on/off depending on the time-domain characteristics of the incoming signal. This study aims paving the way for the design of antenna systems equipped with both frequency- and time-domain selectivity properties.