A Novel Microstrip Quasi Yagi Array Antenna With Annular Sector Directors

A novel directional microstrip quasi Yagi array antenna is proposed to achieve a wide bandwidth with a low profile and a compact structure. The array is composed of a driven circular sector and annular sector directors. Arrays with both a single director and a dual director have been studied. Measured results show that the proposed antenna provides a stable high gain in a wide bandwidth with a low profile of 1.5 mm (0.03λ0 at 5.8 GHz). For an array using a single annular sector director, an impedance bandwidth of 13.6% (5.10-5.85 GHz) is achieved with a peak gain of 8.2 dBi. With two annular sector directors, the bandwidth is improved to 17.6% (5.05-6.02 GHz), and the peak gain is 10 dBi.