Ultra-Wideband Antipodal Tapered Slot Antenna With Integrated Frequency-Notch Characteristics

This communication presents the design of an ultra-wideband antipodal tapered slot antenna (ATSA) with frequency notch characteristics. Subwavelength resonators in the form of square split-ring resonators are placed on the aperture as well as on the feed section of the ATSA to invoke the frequency notches. The electromagnetic coupling of the SRRs with the radiating aperture and with the magnetic fields due to the fringing at the microstrip line feed yields the frequency notches. The invoked notches are sharp in comparison with previously reported designs. The fabricated prototypes were experimentally verified through measurements, and a good agreement with simulations was obtained. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated.