A Dual-Band Low-Profile Microstrip Antenna with Fan-Shaped and Rectangular Beams

Abstract

In this article, a dual-frequency microstrip antenna capable of radiating sector beams and rectangular beams is designed. Firstly, the characteristic mode of microstrip antennas is analyzed, and the principle of half-power beam width (HPBW) enhancement of microstrip antennas is studied from the mode combination theory. Studies have shown that when multiple eigenmodes are excited simultaneously at the same frequency point, the radiation modes can be combined to widen the E-plane HPBW. The measurement results indicate that the S11 of the antenna in the two frequency bands is less than −25 dB. In particular, the microstrip antenna E-plane HPBW of the design received a 60° extension. While radiating a wide fan bundle at low frequency points, the HPBW of the E plane extends significantly to 141°. Radiate rectangular beams at high frequency points have an H-plane HPBW beam width of 90° and an E-plane HPBW beam width of 100°.