A Low-Profile Dual-Band Co-Aperture Monopole Antenna Based on Cross-Layer Folded Structure

This paper presents a dual-band co-aperture monopolar antenna with a very low profile. A novel cross-layer folded structure is first constructed to radiate in the lower band. Meanwhile, it provides enough space for another higher-band section. Then, a via-loaded circular patch is added to the reserved space, and the dual-band co-aperture antenna with independent band performance is obtained. By employing two pairs of similar modes in the two bands, the proposed antenna achieves a relatively large bandwidth of 10.9% in the lower band and 14.6% in the upper band with a thickness of 3.14 mm. Stable conical beam are achieved within both bands and the gains in the lower and upper bands are 5.2-5.8 and 3.7-5 dBi, respectively.