Filtering Antenna Design and Implementation Techniques: Applications, Recent Developments, Challenges, and Future Opportunities

Antennas and filters are two key components that make up the configuration of the radio frequency (RF) front end of any wireless communication system. While the antenna is responsible for transmitting and receiving signals in the system, the filter is tasked with selecting signals that fall within the system’s operating frequency band, while also rejecting spurious (out‐of‐band) signals from the system. Following the recent increasing trend toward device simplicity and miniaturization, it is desirable to integrate the antenna and the filter into a single component that achieves both the radiating (i.e., transmitting and receiving) and the filtering functions simultaneously. This integrated component is what is now known as a filtering antenna (or filtenna). The filtenna reduces a system’s prefiltering requirements and improves the noise performance of the system. It also finds application in overcoming the insufficiency of stand‐alone bandpass filters in suppressing interference in sidebands. This article covers the review of the current state of the art in the design and implementation of filtennas, the practical applications, recent developments, and challenges. Emerging research and future opportunities in filtering antenna design and implementation techniques are also investigated and reported.