A broadband planar quasi-Yagi antenna

TLDR

The antenna should find wide applications in wireless communication systems, power combining, phased arrays and active arrays, as well as millimeter‑wave imaging arrays. A novel broadband planar antenna based on the classic Yagi‑Uda dipole array is presented. The antenna was optimized using finite‑difference time‑domain simulation, validated by measurements, and implemented on a high‑dielectric substrate compatible with microstrip circuitry, with a gain‑enhanced variant trading bandwidth for higher gain. The quasi‑Yagi delivers 48 % bandwidth (VSWR < 2), >12 dB front‑to‑back ratio, <−15 dB cross‑polarization, 3–5 dB absolute gain, 93 % efficiency, and a gain‑enhanced variant trades bandwidth for higher gain, making it suitable as a stand‑alone or array element.

Abstract

A novel broadband planar antenna based on the classic Yagi-Uda dipole array is presented. This "quasi-Yagi" antenna achieves a measured 48% bandwidth for VSWR <2, better than 12 dB front-to-back ratio, smaller than -15 dB cross polarization, 3-5 dB absolute gain and a nominal efficiency of 93% across the operating bandwidth. Finite-difference time-domain simulation is used for optimization of the antenna and the results agree very well with measurements. Additionally, a gain-enhanced design is presented, where higher gain has been achieved at the cost of reduced bandwidth. These quasi-Yagi antennas are realized on a high dielectric constant substrate and are completely compatible with microstrip circuitry and solid-state devices. The excellent radiation properties of this antenna make it ideal as either a stand-alone antenna with a broad pattern or as an array element. The antenna should find wide applications in wireless communication systems, power combining, phased arrays and active arrays, as well as millimeter-wave imaging arrays.