Electronically Reconfigurable Filtennas for S-band and X-band Operation

#antenna #filter #tuning #S-band #X-band #co-design #filtenna

Next-generation wireless RF systems are expected to contain multi-functional, highly flexible, and tightly integrated front-ends for achieving agile use of the frequency spectrum. In the past decade, this has led to research on filtering antennas, or filtennas, in which the functionality of the antenna and filter is combined into a single highly integrated module that achieves the function of both components with a higher-order transfer function. These filtennas can have improved performance, size, and cost. Furthermore, by incorporating frequency-agility, a filtenna can provide adaptation to changing radio environments. One of the challenges in realizing a reconfigurable filtenna is that two dissimilar elements need to be tuned in tandem.

This presentation covers recent developments in the design of reconfigurable filtennas in the S-band (2-4 GHz) and X-band (8-12 GHz). The filtennas are based on using evanescent-mode cavities as the backing for slot antennas. A discussion of available tuning mechanisms and the challenges of going from S-band to X-band is included. Second-order reconfigurable filtenna proof-of-concept prototypes are shown in both frequency bands. The prototype filtennas are created using commercially available printed circuit board materials and tuning elements and measured in an anechoic chamber. The S-band filtenna can continuously tune from 2 to 2.6 GHz while achieving a realized gain between 2.7 to 5.2 dB, respectively. The X-band filtenna demonstrates tuning from 9.6 to 11.1 GHz, with a maximum gain of 5 dB. Overall, with the demonstrated performance, these elements are promising components for future wireless communications and radar systems.