Ultrawideband Low-Profile Transmitarray With Vivaldi Array Feed

• Published in: IEEE transactions on antennas and propagation Vol. 68; no. 4; pp. 3265 - 3270
• Main Authors: Feng, Peng-Yu, Qu, Shi-Wei, Yang, Shiwen
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna arrays; Antennas; Computer simulation; Cost function; Diameters; Feeds; Frequencies; Lens antennas; Manganese; Optimization; periodic structures; phased array antennas (PAAs); Phased arrays; Polarizers; Sidelobes; transmitarrays; Transmitting antennas; Ultra wideband antennas; Ultrawideband; ultrawideband antenna arrays
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2020.2969702

A transmitarray antenna (TAA) with a small-scale phased array antenna (PAA) feed is proposed in this communication. After modeling the PAA-fed TAAs and constructing the cost functions, a three-step optimization process is introduced to determine the TAA element arrangement as well as the PAA feed excitation coefficients. Then, a novel ultrawideband TAA element is proposed, which has a pair of connected sheep-horn metallic patterns in the middle layer sandwiched by two metallic orthogonal grid polarizers on the upper and bottom layers. Furthermore, traditional Vivaldi antenna element is identified as the element of a <inline-formula> <tex-math notation="LaTeX">4 \times 8 </tex-math></inline-formula>-element PAA feed array (central <inline-formula> <tex-math notation="LaTeX">4\times 4 </tex-math></inline-formula> active elements), which is employed to illuminate a <inline-formula> <tex-math notation="LaTeX">25\times 25 </tex-math></inline-formula>-element circular TAA with a focus-to-diameter (<inline-formula> <tex-math notation="LaTeX">F/D) </tex-math></inline-formula> ratio of mere 0.43. The simulated results show that stable radiation patterns with good main beam shapes and reasonable sidelobe levels are obtained in the interested frequency band. The measured results agree reasonably well with the simulated ones, validating the feasibility of our method to design an ultrawideband low-profile PAA-fed TAA.